xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision 2f5188fd5894b873e39e377d488ba22e3f22f084)
1 //===- ARMDisassembler.cpp - Disassembler for ARM/Thumb ISA ---------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "ARMBaseInstrInfo.h"
10 #include "MCTargetDesc/ARMAddressingModes.h"
11 #include "MCTargetDesc/ARMBaseInfo.h"
12 #include "MCTargetDesc/ARMMCTargetDesc.h"
13 #include "TargetInfo/ARMTargetInfo.h"
14 #include "Utils/ARMBaseInfo.h"
15 #include "llvm/MC/MCContext.h"
16 #include "llvm/MC/MCDisassembler/MCDisassembler.h"
17 #include "llvm/MC/MCFixedLenDisassembler.h"
18 #include "llvm/MC/MCInst.h"
19 #include "llvm/MC/MCInstrDesc.h"
20 #include "llvm/MC/MCSubtargetInfo.h"
21 #include "llvm/MC/SubtargetFeature.h"
22 #include "llvm/Support/Compiler.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/MathExtras.h"
25 #include "llvm/Support/TargetRegistry.h"
26 #include "llvm/Support/raw_ostream.h"
27 #include <algorithm>
28 #include <cassert>
29 #include <cstdint>
30 #include <vector>
31 
32 using namespace llvm;
33 
34 #define DEBUG_TYPE "arm-disassembler"
35 
36 using DecodeStatus = MCDisassembler::DecodeStatus;
37 
38 namespace {
39 
40   // Handles the condition code status of instructions in IT blocks
41   class ITStatus
42   {
43     public:
44       // Returns the condition code for instruction in IT block
45       unsigned getITCC() {
46         unsigned CC = ARMCC::AL;
47         if (instrInITBlock())
48           CC = ITStates.back();
49         return CC;
50       }
51 
52       // Advances the IT block state to the next T or E
53       void advanceITState() {
54         ITStates.pop_back();
55       }
56 
57       // Returns true if the current instruction is in an IT block
58       bool instrInITBlock() {
59         return !ITStates.empty();
60       }
61 
62       // Returns true if current instruction is the last instruction in an IT block
63       bool instrLastInITBlock() {
64         return ITStates.size() == 1;
65       }
66 
67       // Called when decoding an IT instruction. Sets the IT state for
68       // the following instructions that for the IT block. Firstcond
69       // corresponds to the field in the IT instruction encoding; Mask
70       // is in the MCOperand format in which 1 means 'else' and 0 'then'.
71       void setITState(char Firstcond, char Mask) {
72         // (3 - the number of trailing zeros) is the number of then / else.
73         unsigned NumTZ = countTrailingZeros<uint8_t>(Mask);
74         unsigned char CCBits = static_cast<unsigned char>(Firstcond & 0xf);
75         assert(NumTZ <= 3 && "Invalid IT mask!");
76         // push condition codes onto the stack the correct order for the pops
77         for (unsigned Pos = NumTZ+1; Pos <= 3; ++Pos) {
78           unsigned Else = (Mask >> Pos) & 1;
79           ITStates.push_back(CCBits ^ Else);
80         }
81         ITStates.push_back(CCBits);
82       }
83 
84     private:
85       std::vector<unsigned char> ITStates;
86   };
87 
88   class VPTStatus
89   {
90     public:
91       unsigned getVPTPred() {
92         unsigned Pred = ARMVCC::None;
93         if (instrInVPTBlock())
94           Pred = VPTStates.back();
95         return Pred;
96       }
97 
98       void advanceVPTState() {
99         VPTStates.pop_back();
100       }
101 
102       bool instrInVPTBlock() {
103         return !VPTStates.empty();
104       }
105 
106       bool instrLastInVPTBlock() {
107         return VPTStates.size() == 1;
108       }
109 
110       void setVPTState(char Mask) {
111         // (3 - the number of trailing zeros) is the number of then / else.
112         unsigned NumTZ = countTrailingZeros<uint8_t>(Mask);
113         assert(NumTZ <= 3 && "Invalid VPT mask!");
114         // push predicates onto the stack the correct order for the pops
115         for (unsigned Pos = NumTZ+1; Pos <= 3; ++Pos) {
116           bool T = ((Mask >> Pos) & 1) == 0;
117           if (T)
118             VPTStates.push_back(ARMVCC::Then);
119           else
120             VPTStates.push_back(ARMVCC::Else);
121         }
122         VPTStates.push_back(ARMVCC::Then);
123       }
124 
125     private:
126       SmallVector<unsigned char, 4> VPTStates;
127   };
128 
129 /// ARM disassembler for all ARM platforms.
130 class ARMDisassembler : public MCDisassembler {
131 public:
132   ARMDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx) :
133     MCDisassembler(STI, Ctx) {
134   }
135 
136   ~ARMDisassembler() override = default;
137 
138   DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
139                               ArrayRef<uint8_t> Bytes, uint64_t Address,
140                               raw_ostream &VStream,
141                               raw_ostream &CStream) const override;
142 };
143 
144 /// Thumb disassembler for all Thumb platforms.
145 class ThumbDisassembler : public MCDisassembler {
146 public:
147   ThumbDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx) :
148     MCDisassembler(STI, Ctx) {
149   }
150 
151   ~ThumbDisassembler() override = default;
152 
153   DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
154                               ArrayRef<uint8_t> Bytes, uint64_t Address,
155                               raw_ostream &VStream,
156                               raw_ostream &CStream) const override;
157 
158 private:
159   mutable ITStatus ITBlock;
160   mutable VPTStatus VPTBlock;
161 
162   DecodeStatus AddThumbPredicate(MCInst&) const;
163   void UpdateThumbVFPPredicate(DecodeStatus &, MCInst&) const;
164 };
165 
166 } // end anonymous namespace
167 
168 static bool Check(DecodeStatus &Out, DecodeStatus In) {
169   switch (In) {
170     case MCDisassembler::Success:
171       // Out stays the same.
172       return true;
173     case MCDisassembler::SoftFail:
174       Out = In;
175       return true;
176     case MCDisassembler::Fail:
177       Out = In;
178       return false;
179   }
180   llvm_unreachable("Invalid DecodeStatus!");
181 }
182 
183 // Forward declare these because the autogenerated code will reference them.
184 // Definitions are further down.
185 static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
186                                    uint64_t Address, const void *Decoder);
187 static DecodeStatus DecodeCLRMGPRRegisterClass(MCInst &Inst, unsigned RegNo,
188                                    uint64_t Address, const void *Decoder);
189 static DecodeStatus DecodetGPROddRegisterClass(MCInst &Inst, unsigned RegNo,
190                                    uint64_t Address, const void *Decoder);
191 static DecodeStatus DecodetGPREvenRegisterClass(MCInst &Inst, unsigned RegNo,
192                                    uint64_t Address, const void *Decoder);
193 static DecodeStatus DecodeGPRnopcRegisterClass(MCInst &Inst,
194                                                unsigned RegNo, uint64_t Address,
195                                                const void *Decoder);
196 static DecodeStatus DecodeGPRwithAPSRRegisterClass(MCInst &Inst,
197                                                unsigned RegNo, uint64_t Address,
198                                                const void *Decoder);
199 static DecodeStatus DecodeGPRwithZRRegisterClass(MCInst &Inst,
200                                                unsigned RegNo, uint64_t Address,
201                                                const void *Decoder);
202 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
203                                    uint64_t Address, const void *Decoder);
204 static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
205                                    uint64_t Address, const void *Decoder);
206 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
207                                    uint64_t Address, const void *Decoder);
208 static DecodeStatus DecodeGPRPairRegisterClass(MCInst &Inst, unsigned RegNo,
209                                    uint64_t Address, const void *Decoder);
210 static DecodeStatus DecodeHPRRegisterClass(MCInst &Inst, unsigned RegNo,
211                                    uint64_t Address, const void *Decoder);
212 static DecodeStatus DecodeSPRRegisterClass(MCInst &Inst, unsigned RegNo,
213                                    uint64_t Address, const void *Decoder);
214 static DecodeStatus DecodeDPRRegisterClass(MCInst &Inst, unsigned RegNo,
215                                    uint64_t Address, const void *Decoder);
216 static DecodeStatus DecodeDPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
217                                    uint64_t Address, const void *Decoder);
218 static DecodeStatus DecodeSPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
219                                    uint64_t Address, const void *Decoder);
220 static DecodeStatus DecodeDPR_VFP2RegisterClass(MCInst &Inst,
221                                                 unsigned RegNo,
222                                                 uint64_t Address,
223                                                 const void *Decoder);
224 static DecodeStatus DecodeQPRRegisterClass(MCInst &Inst, unsigned RegNo,
225                                    uint64_t Address, const void *Decoder);
226 static DecodeStatus DecodeMQPRRegisterClass(MCInst &Inst, unsigned RegNo,
227                                    uint64_t Address, const void *Decoder);
228 static DecodeStatus DecodeDPairRegisterClass(MCInst &Inst, unsigned RegNo,
229                                    uint64_t Address, const void *Decoder);
230 static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst &Inst,
231                                unsigned RegNo, uint64_t Address,
232                                const void *Decoder);
233 
234 static DecodeStatus DecodePredicateOperand(MCInst &Inst, unsigned Val,
235                                uint64_t Address, const void *Decoder);
236 static DecodeStatus DecodeCCOutOperand(MCInst &Inst, unsigned Val,
237                                uint64_t Address, const void *Decoder);
238 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
239                                uint64_t Address, const void *Decoder);
240 static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
241                                uint64_t Address, const void *Decoder);
242 static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
243                                uint64_t Address, const void *Decoder);
244 
245 static DecodeStatus DecodeBitfieldMaskOperand(MCInst &Inst, unsigned Insn,
246                                uint64_t Address, const void *Decoder);
247 static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
248                                uint64_t Address, const void *Decoder);
249 static DecodeStatus DecodeAddrMode2IdxInstruction(MCInst &Inst,
250                                                   unsigned Insn,
251                                                   uint64_t Address,
252                                                   const void *Decoder);
253 static DecodeStatus DecodeSORegMemOperand(MCInst &Inst, unsigned Insn,
254                                uint64_t Address, const void *Decoder);
255 static DecodeStatus DecodeAddrMode3Instruction(MCInst &Inst,unsigned Insn,
256                                uint64_t Address, const void *Decoder);
257 static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Insn,
258                                uint64_t Address, const void *Decoder);
259 static DecodeStatus DecodeSORegRegOperand(MCInst &Inst, unsigned Insn,
260                                uint64_t Address, const void *Decoder);
261 
262 static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst & Inst,
263                                                   unsigned Insn,
264                                                   uint64_t Adddress,
265                                                   const void *Decoder);
266 static DecodeStatus DecodeT2MOVTWInstruction(MCInst &Inst, unsigned Insn,
267                                uint64_t Address, const void *Decoder);
268 static DecodeStatus DecodeArmMOVTWInstruction(MCInst &Inst, unsigned Insn,
269                                uint64_t Address, const void *Decoder);
270 static DecodeStatus DecodeSMLAInstruction(MCInst &Inst, unsigned Insn,
271                                uint64_t Address, const void *Decoder);
272 static DecodeStatus DecodeHINTInstruction(MCInst &Inst, unsigned Insn,
273                                uint64_t Address, const void *Decoder);
274 static DecodeStatus DecodeCPSInstruction(MCInst &Inst, unsigned Insn,
275                                uint64_t Address, const void *Decoder);
276 static DecodeStatus DecodeTSTInstruction(MCInst &Inst, unsigned Insn,
277                                uint64_t Address, const void *Decoder);
278 static DecodeStatus DecodeSETPANInstruction(MCInst &Inst, unsigned Insn,
279                                uint64_t Address, const void *Decoder);
280 static DecodeStatus DecodeT2CPSInstruction(MCInst &Inst, unsigned Insn,
281                                uint64_t Address, const void *Decoder);
282 static DecodeStatus DecodeAddrModeImm12Operand(MCInst &Inst, unsigned Val,
283                                uint64_t Address, const void *Decoder);
284 static DecodeStatus DecodeAddrMode5Operand(MCInst &Inst, unsigned Val,
285                                uint64_t Address, const void *Decoder);
286 static DecodeStatus DecodeAddrMode5FP16Operand(MCInst &Inst, unsigned Val,
287                                uint64_t Address, const void *Decoder);
288 static DecodeStatus DecodeAddrMode7Operand(MCInst &Inst, unsigned Val,
289                                uint64_t Address, const void *Decoder);
290 static DecodeStatus DecodeT2BInstruction(MCInst &Inst, unsigned Insn,
291                                uint64_t Address, const void *Decoder);
292 static DecodeStatus DecodeBranchImmInstruction(MCInst &Inst,unsigned Insn,
293                                uint64_t Address, const void *Decoder);
294 static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
295                                uint64_t Address, const void *Decoder);
296 static DecodeStatus DecodeVLDST1Instruction(MCInst &Inst, unsigned Val,
297                                uint64_t Address, const void *Decoder);
298 static DecodeStatus DecodeVLDST2Instruction(MCInst &Inst, unsigned Val,
299                                uint64_t Address, const void *Decoder);
300 static DecodeStatus DecodeVLDST3Instruction(MCInst &Inst, unsigned Val,
301                                uint64_t Address, const void *Decoder);
302 static DecodeStatus DecodeVLDST4Instruction(MCInst &Inst, unsigned Val,
303                                uint64_t Address, const void *Decoder);
304 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Val,
305                                uint64_t Address, const void *Decoder);
306 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Val,
307                                uint64_t Address, const void *Decoder);
308 static DecodeStatus DecodeVLD1DupInstruction(MCInst &Inst, unsigned Val,
309                                uint64_t Address, const void *Decoder);
310 static DecodeStatus DecodeVLD2DupInstruction(MCInst &Inst, unsigned Val,
311                                uint64_t Address, const void *Decoder);
312 static DecodeStatus DecodeVLD3DupInstruction(MCInst &Inst, unsigned Val,
313                                uint64_t Address, const void *Decoder);
314 static DecodeStatus DecodeVLD4DupInstruction(MCInst &Inst, unsigned Val,
315                                uint64_t Address, const void *Decoder);
316 static DecodeStatus DecodeNEONModImmInstruction(MCInst &Inst,unsigned Val,
317                                uint64_t Address, const void *Decoder);
318 static DecodeStatus DecodeVSHLMaxInstruction(MCInst &Inst, unsigned Val,
319                                uint64_t Address, const void *Decoder);
320 static DecodeStatus DecodeShiftRight8Imm(MCInst &Inst, unsigned Val,
321                                uint64_t Address, const void *Decoder);
322 static DecodeStatus DecodeShiftRight16Imm(MCInst &Inst, unsigned Val,
323                                uint64_t Address, const void *Decoder);
324 static DecodeStatus DecodeShiftRight32Imm(MCInst &Inst, unsigned Val,
325                                uint64_t Address, const void *Decoder);
326 static DecodeStatus DecodeShiftRight64Imm(MCInst &Inst, unsigned Val,
327                                uint64_t Address, const void *Decoder);
328 static DecodeStatus DecodeTBLInstruction(MCInst &Inst, unsigned Insn,
329                                uint64_t Address, const void *Decoder);
330 static DecodeStatus DecodePostIdxReg(MCInst &Inst, unsigned Insn,
331                                uint64_t Address, const void *Decoder);
332 static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Insn,
333                                uint64_t Address, const void *Decoder);
334 static DecodeStatus DecodeMemBarrierOption(MCInst &Inst, unsigned Insn,
335                                uint64_t Address, const void *Decoder);
336 static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Insn,
337                                uint64_t Address, const void *Decoder);
338 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Insn,
339                                uint64_t Address, const void *Decoder);
340 static DecodeStatus DecodeBankedReg(MCInst &Inst, unsigned Insn,
341                                uint64_t Address, const void *Decoder);
342 static DecodeStatus DecodeDoubleRegLoad(MCInst &Inst, unsigned Insn,
343                                uint64_t Address, const void *Decoder);
344 static DecodeStatus DecodeDoubleRegStore(MCInst &Inst, unsigned Insn,
345                                uint64_t Address, const void *Decoder);
346 static DecodeStatus DecodeLDRPreImm(MCInst &Inst, unsigned Insn,
347                                uint64_t Address, const void *Decoder);
348 static DecodeStatus DecodeLDRPreReg(MCInst &Inst, unsigned Insn,
349                                uint64_t Address, const void *Decoder);
350 static DecodeStatus DecodeSTRPreImm(MCInst &Inst, unsigned Insn,
351                                uint64_t Address, const void *Decoder);
352 static DecodeStatus DecodeSTRPreReg(MCInst &Inst, unsigned Insn,
353                                uint64_t Address, const void *Decoder);
354 static DecodeStatus DecodeVLD1LN(MCInst &Inst, unsigned Insn,
355                                uint64_t Address, const void *Decoder);
356 static DecodeStatus DecodeVLD2LN(MCInst &Inst, unsigned Insn,
357                                uint64_t Address, const void *Decoder);
358 static DecodeStatus DecodeVLD3LN(MCInst &Inst, unsigned Insn,
359                                uint64_t Address, const void *Decoder);
360 static DecodeStatus DecodeVLD4LN(MCInst &Inst, unsigned Insn,
361                                uint64_t Address, const void *Decoder);
362 static DecodeStatus DecodeVST1LN(MCInst &Inst, unsigned Insn,
363                                uint64_t Address, const void *Decoder);
364 static DecodeStatus DecodeVST2LN(MCInst &Inst, unsigned Insn,
365                                uint64_t Address, const void *Decoder);
366 static DecodeStatus DecodeVST3LN(MCInst &Inst, unsigned Insn,
367                                uint64_t Address, const void *Decoder);
368 static DecodeStatus DecodeVST4LN(MCInst &Inst, unsigned Insn,
369                                uint64_t Address, const void *Decoder);
370 static DecodeStatus DecodeVMOVSRR(MCInst &Inst, unsigned Insn,
371                                uint64_t Address, const void *Decoder);
372 static DecodeStatus DecodeVMOVRRS(MCInst &Inst, unsigned Insn,
373                                uint64_t Address, const void *Decoder);
374 static DecodeStatus DecodeSwap(MCInst &Inst, unsigned Insn,
375                                uint64_t Address, const void *Decoder);
376 static DecodeStatus DecodeVCVTD(MCInst &Inst, unsigned Insn,
377                                 uint64_t Address, const void *Decoder);
378 static DecodeStatus DecodeVCVTQ(MCInst &Inst, unsigned Insn,
379                                 uint64_t Address, const void *Decoder);
380 static DecodeStatus DecodeNEONComplexLane64Instruction(MCInst &Inst,
381                                                        unsigned Val,
382                                                        uint64_t Address,
383                                                        const void *Decoder);
384 
385 static DecodeStatus DecodeThumbAddSpecialReg(MCInst &Inst, uint16_t Insn,
386                                uint64_t Address, const void *Decoder);
387 static DecodeStatus DecodeThumbBROperand(MCInst &Inst, unsigned Val,
388                                uint64_t Address, const void *Decoder);
389 static DecodeStatus DecodeT2BROperand(MCInst &Inst, unsigned Val,
390                                uint64_t Address, const void *Decoder);
391 static DecodeStatus DecodeThumbCmpBROperand(MCInst &Inst, unsigned Val,
392                                uint64_t Address, const void *Decoder);
393 static DecodeStatus DecodeThumbAddrModeRR(MCInst &Inst, unsigned Val,
394                                uint64_t Address, const void *Decoder);
395 static DecodeStatus DecodeThumbAddrModeIS(MCInst &Inst, unsigned Val,
396                                uint64_t Address, const void *Decoder);
397 static DecodeStatus DecodeThumbAddrModePC(MCInst &Inst, unsigned Val,
398                                uint64_t Address, const void *Decoder);
399 static DecodeStatus DecodeThumbAddrModeSP(MCInst &Inst, unsigned Val,
400                                uint64_t Address, const void *Decoder);
401 static DecodeStatus DecodeT2AddrModeSOReg(MCInst &Inst, unsigned Val,
402                                uint64_t Address, const void *Decoder);
403 static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Val,
404                                uint64_t Address, const void *Decoder);
405 static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
406                                uint64_t Address, const void* Decoder);
407 static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
408                                uint64_t Address, const void* Decoder);
409 static DecodeStatus DecodeT2LoadT(MCInst &Inst, unsigned Insn,
410                                uint64_t Address, const void* Decoder);
411 static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
412                                uint64_t Address, const void* Decoder);
413 static DecodeStatus DecodeT2Imm8S4(MCInst &Inst, unsigned Val,
414                                uint64_t Address, const void *Decoder);
415 static DecodeStatus DecodeT2Imm7S4(MCInst &Inst, unsigned Val,
416                                uint64_t Address, const void *Decoder);
417 static DecodeStatus DecodeT2AddrModeImm8s4(MCInst &Inst, unsigned Val,
418                                uint64_t Address, const void *Decoder);
419 static DecodeStatus DecodeT2AddrModeImm7s4(MCInst &Inst, unsigned Val,
420                                            uint64_t Address,
421                                            const void *Decoder);
422 static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst &Inst,unsigned Val,
423                                uint64_t Address, const void *Decoder);
424 static DecodeStatus DecodeT2Imm8(MCInst &Inst, unsigned Val,
425                                uint64_t Address, const void *Decoder);
426 static DecodeStatus DecodeT2AddrModeImm8(MCInst &Inst, unsigned Val,
427                                uint64_t Address, const void *Decoder);
428 static DecodeStatus DecodeThumbAddSPImm(MCInst &Inst, uint16_t Val,
429                                uint64_t Address, const void *Decoder);
430 static DecodeStatus DecodeThumbAddSPReg(MCInst &Inst, uint16_t Insn,
431                                 uint64_t Address, const void *Decoder);
432 static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
433                                 uint64_t Address, const void *Decoder);
434 static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
435                                 uint64_t Address, const void *Decoder);
436 static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Insn,
437                                 uint64_t Address, const void *Decoder);
438 static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
439                                 uint64_t Address, const void *Decoder);
440 static DecodeStatus DecodeThumbTableBranch(MCInst &Inst, unsigned Val,
441                                 uint64_t Address, const void *Decoder);
442 static DecodeStatus DecodeThumb2BCCInstruction(MCInst &Inst, unsigned Val,
443                                 uint64_t Address, const void *Decoder);
444 static DecodeStatus DecodeT2SOImm(MCInst &Inst, unsigned Val,
445                                 uint64_t Address, const void *Decoder);
446 static DecodeStatus DecodeThumbBCCTargetOperand(MCInst &Inst,unsigned Val,
447                                 uint64_t Address, const void *Decoder);
448 static DecodeStatus DecodeThumbBLTargetOperand(MCInst &Inst, unsigned Val,
449                                 uint64_t Address, const void *Decoder);
450 static DecodeStatus DecodeIT(MCInst &Inst, unsigned Val,
451                                 uint64_t Address, const void *Decoder);
452 static DecodeStatus DecodeT2LDRDPreInstruction(MCInst &Inst,unsigned Insn,
453                                uint64_t Address, const void *Decoder);
454 static DecodeStatus DecodeT2STRDPreInstruction(MCInst &Inst,unsigned Insn,
455                                uint64_t Address, const void *Decoder);
456 static DecodeStatus DecodeT2Adr(MCInst &Inst, unsigned Val,
457                                 uint64_t Address, const void *Decoder);
458 static DecodeStatus DecodeT2LdStPre(MCInst &Inst, unsigned Val,
459                                 uint64_t Address, const void *Decoder);
460 static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, unsigned Val,
461                                 uint64_t Address, const void *Decoder);
462 
463 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
464                                 uint64_t Address, const void *Decoder);
465 static DecodeStatus DecoderForMRRC2AndMCRR2(MCInst &Inst, unsigned Val,
466                                             uint64_t Address, const void *Decoder);
467 static DecodeStatus DecodeForVMRSandVMSR(MCInst &Inst, unsigned Val,
468                                          uint64_t Address, const void *Decoder);
469 
470 template <bool isSigned, bool isNeg, int size>
471 static DecodeStatus DecodeBFLabelOperand(MCInst &Inst, unsigned val,
472                                          uint64_t Address, const void *Decoder);
473 static DecodeStatus DecodeBFAfterTargetOperand(MCInst &Inst, unsigned val,
474                                                uint64_t Address,
475                                                const void *Decoder);
476 static DecodeStatus DecodePredNoALOperand(MCInst &Inst, unsigned Val,
477                                           uint64_t Address,
478                                           const void *Decoder);
479 static DecodeStatus DecodeLOLoop(MCInst &Inst, unsigned Insn, uint64_t Address,
480                                  const void *Decoder);
481 static DecodeStatus DecodeLongShiftOperand(MCInst &Inst, unsigned Val,
482                                            uint64_t Address,
483                                            const void *Decoder);
484 static DecodeStatus DecodeVSCCLRM(MCInst &Inst, unsigned Insn, uint64_t Address,
485                                   const void *Decoder);
486 static DecodeStatus DecodeVPTMaskOperand(MCInst &Inst, unsigned Val,
487                                          uint64_t Address, const void *Decoder);
488 static DecodeStatus DecodeVpredROperand(MCInst &Inst, unsigned Val,
489                                         uint64_t Address, const void *Decoder);
490 static DecodeStatus DecodeRestrictedIPredicateOperand(MCInst &Inst, unsigned Val,
491                                                      uint64_t Address,
492                                                      const void *Decoder);
493 static DecodeStatus DecodeRestrictedSPredicateOperand(MCInst &Inst, unsigned Val,
494                                                      uint64_t Address,
495                                                      const void *Decoder);
496 static DecodeStatus DecodeRestrictedUPredicateOperand(MCInst &Inst, unsigned Val,
497                                                      uint64_t Address,
498                                                      const void *Decoder);
499 static DecodeStatus DecodeRestrictedFPPredicateOperand(MCInst &Inst,
500                                                        unsigned Val,
501                                                        uint64_t Address,
502                                                        const void *Decoder);
503 template<bool Writeback>
504 static DecodeStatus DecodeVSTRVLDR_SYSREG(MCInst &Inst, unsigned Insn,
505                                           uint64_t Address,
506                                           const void *Decoder);
507 template <int shift>
508 static DecodeStatus DecodeExpandedImmOperand(MCInst &Inst, unsigned Val,
509                                              uint64_t Address,
510                                              const void *Decoder);
511 static DecodeStatus DecodeMVEOverlappingLongShift(MCInst &Inst, unsigned Insn,
512                                                   uint64_t Address,
513                                                   const void *Decoder);
514 #include "ARMGenDisassemblerTables.inc"
515 
516 static MCDisassembler *createARMDisassembler(const Target &T,
517                                              const MCSubtargetInfo &STI,
518                                              MCContext &Ctx) {
519   return new ARMDisassembler(STI, Ctx);
520 }
521 
522 static MCDisassembler *createThumbDisassembler(const Target &T,
523                                                const MCSubtargetInfo &STI,
524                                                MCContext &Ctx) {
525   return new ThumbDisassembler(STI, Ctx);
526 }
527 
528 // Post-decoding checks
529 static DecodeStatus checkDecodedInstruction(MCInst &MI, uint64_t &Size,
530                                             uint64_t Address, raw_ostream &OS,
531                                             raw_ostream &CS,
532                                             uint32_t Insn,
533                                             DecodeStatus Result) {
534   switch (MI.getOpcode()) {
535     case ARM::HVC: {
536       // HVC is undefined if condition = 0xf otherwise upredictable
537       // if condition != 0xe
538       uint32_t Cond = (Insn >> 28) & 0xF;
539       if (Cond == 0xF)
540         return MCDisassembler::Fail;
541       if (Cond != 0xE)
542         return MCDisassembler::SoftFail;
543       return Result;
544     }
545     case ARM::t2ADDri:
546     case ARM::t2ADDri12:
547     case ARM::t2ADDrr:
548     case ARM::t2ADDrs:
549     case ARM::t2SUBri:
550     case ARM::t2SUBri12:
551     case ARM::t2SUBrr:
552     case ARM::t2SUBrs:
553       if (MI.getOperand(0).getReg() == ARM::SP &&
554           MI.getOperand(1).getReg() != ARM::SP)
555         return MCDisassembler::SoftFail;
556       return Result;
557     default: return Result;
558   }
559 }
560 
561 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
562                                              ArrayRef<uint8_t> Bytes,
563                                              uint64_t Address, raw_ostream &OS,
564                                              raw_ostream &CS) const {
565   CommentStream = &CS;
566 
567   assert(!STI.getFeatureBits()[ARM::ModeThumb] &&
568          "Asked to disassemble an ARM instruction but Subtarget is in Thumb "
569          "mode!");
570 
571   // We want to read exactly 4 bytes of data.
572   if (Bytes.size() < 4) {
573     Size = 0;
574     return MCDisassembler::Fail;
575   }
576 
577   // Encoded as a small-endian 32-bit word in the stream.
578   uint32_t Insn =
579       (Bytes[3] << 24) | (Bytes[2] << 16) | (Bytes[1] << 8) | (Bytes[0] << 0);
580 
581   // Calling the auto-generated decoder function.
582   DecodeStatus Result =
583       decodeInstruction(DecoderTableARM32, MI, Insn, Address, this, STI);
584   if (Result != MCDisassembler::Fail) {
585     Size = 4;
586     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
587   }
588 
589   struct DecodeTable {
590     const uint8_t *P;
591     bool DecodePred;
592   };
593 
594   const DecodeTable Tables[] = {
595       {DecoderTableVFP32, false},      {DecoderTableVFPV832, false},
596       {DecoderTableNEONData32, true},  {DecoderTableNEONLoadStore32, true},
597       {DecoderTableNEONDup32, true},   {DecoderTablev8NEON32, false},
598       {DecoderTablev8Crypto32, false},
599   };
600 
601   for (auto Table : Tables) {
602     Result = decodeInstruction(Table.P, MI, Insn, Address, this, STI);
603     if (Result != MCDisassembler::Fail) {
604       Size = 4;
605       // Add a fake predicate operand, because we share these instruction
606       // definitions with Thumb2 where these instructions are predicable.
607       if (Table.DecodePred && !DecodePredicateOperand(MI, 0xE, Address, this))
608         return MCDisassembler::Fail;
609       return Result;
610     }
611   }
612 
613   Result =
614       decodeInstruction(DecoderTableCoProc32, MI, Insn, Address, this, STI);
615   if (Result != MCDisassembler::Fail) {
616     Size = 4;
617     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
618   }
619 
620   Size = 4;
621   return MCDisassembler::Fail;
622 }
623 
624 namespace llvm {
625 
626 extern const MCInstrDesc ARMInsts[];
627 
628 } // end namespace llvm
629 
630 /// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the
631 /// immediate Value in the MCInst.  The immediate Value has had any PC
632 /// adjustment made by the caller.  If the instruction is a branch instruction
633 /// then isBranch is true, else false.  If the getOpInfo() function was set as
634 /// part of the setupForSymbolicDisassembly() call then that function is called
635 /// to get any symbolic information at the Address for this instruction.  If
636 /// that returns non-zero then the symbolic information it returns is used to
637 /// create an MCExpr and that is added as an operand to the MCInst.  If
638 /// getOpInfo() returns zero and isBranch is true then a symbol look up for
639 /// Value is done and if a symbol is found an MCExpr is created with that, else
640 /// an MCExpr with Value is created.  This function returns true if it adds an
641 /// operand to the MCInst and false otherwise.
642 static bool tryAddingSymbolicOperand(uint64_t Address, int32_t Value,
643                                      bool isBranch, uint64_t InstSize,
644                                      MCInst &MI, const void *Decoder) {
645   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
646   // FIXME: Does it make sense for value to be negative?
647   return Dis->tryAddingSymbolicOperand(MI, (uint32_t)Value, Address, isBranch,
648                                        /* Offset */ 0, InstSize);
649 }
650 
651 /// tryAddingPcLoadReferenceComment - trys to add a comment as to what is being
652 /// referenced by a load instruction with the base register that is the Pc.
653 /// These can often be values in a literal pool near the Address of the
654 /// instruction.  The Address of the instruction and its immediate Value are
655 /// used as a possible literal pool entry.  The SymbolLookUp call back will
656 /// return the name of a symbol referenced by the literal pool's entry if
657 /// the referenced address is that of a symbol.  Or it will return a pointer to
658 /// a literal 'C' string if the referenced address of the literal pool's entry
659 /// is an address into a section with 'C' string literals.
660 static void tryAddingPcLoadReferenceComment(uint64_t Address, int Value,
661                                             const void *Decoder) {
662   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
663   Dis->tryAddingPcLoadReferenceComment(Value, Address);
664 }
665 
666 // Thumb1 instructions don't have explicit S bits.  Rather, they
667 // implicitly set CPSR.  Since it's not represented in the encoding, the
668 // auto-generated decoder won't inject the CPSR operand.  We need to fix
669 // that as a post-pass.
670 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
671   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
672   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
673   MCInst::iterator I = MI.begin();
674   for (unsigned i = 0; i < NumOps; ++i, ++I) {
675     if (I == MI.end()) break;
676     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
677       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
678       MI.insert(I, MCOperand::createReg(InITBlock ? 0 : ARM::CPSR));
679       return;
680     }
681   }
682 
683   MI.insert(I, MCOperand::createReg(InITBlock ? 0 : ARM::CPSR));
684 }
685 
686 static bool isVectorPredicable(unsigned Opcode) {
687   const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
688   unsigned short NumOps = ARMInsts[Opcode].NumOperands;
689   for (unsigned i = 0; i < NumOps; ++i) {
690     if (ARM::isVpred(OpInfo[i].OperandType))
691       return true;
692   }
693   return false;
694 }
695 
696 // Most Thumb instructions don't have explicit predicates in the
697 // encoding, but rather get their predicates from IT context.  We need
698 // to fix up the predicate operands using this context information as a
699 // post-pass.
700 MCDisassembler::DecodeStatus
701 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
702   MCDisassembler::DecodeStatus S = Success;
703 
704   const FeatureBitset &FeatureBits = getSubtargetInfo().getFeatureBits();
705 
706   // A few instructions actually have predicates encoded in them.  Don't
707   // try to overwrite it if we're seeing one of those.
708   switch (MI.getOpcode()) {
709     case ARM::tBcc:
710     case ARM::t2Bcc:
711     case ARM::tCBZ:
712     case ARM::tCBNZ:
713     case ARM::tCPS:
714     case ARM::t2CPS3p:
715     case ARM::t2CPS2p:
716     case ARM::t2CPS1p:
717     case ARM::t2CSEL:
718     case ARM::t2CSINC:
719     case ARM::t2CSINV:
720     case ARM::t2CSNEG:
721     case ARM::tMOVSr:
722     case ARM::tSETEND:
723       // Some instructions (mostly conditional branches) are not
724       // allowed in IT blocks.
725       if (ITBlock.instrInITBlock())
726         S = SoftFail;
727       else
728         return Success;
729       break;
730     case ARM::t2HINT:
731       if (MI.getOperand(0).getImm() == 0x10 && (FeatureBits[ARM::FeatureRAS]) != 0)
732         S = SoftFail;
733       break;
734     case ARM::tB:
735     case ARM::t2B:
736     case ARM::t2TBB:
737     case ARM::t2TBH:
738       // Some instructions (mostly unconditional branches) can
739       // only appears at the end of, or outside of, an IT.
740       if (ITBlock.instrInITBlock() && !ITBlock.instrLastInITBlock())
741         S = SoftFail;
742       break;
743     default:
744       break;
745   }
746 
747   // Warn on non-VPT predicable instruction in a VPT block and a VPT
748   // predicable instruction in an IT block
749   if ((!isVectorPredicable(MI.getOpcode()) && VPTBlock.instrInVPTBlock()) ||
750        (isVectorPredicable(MI.getOpcode()) && ITBlock.instrInITBlock()))
751     S = SoftFail;
752 
753   // If we're in an IT/VPT block, base the predicate on that.  Otherwise,
754   // assume a predicate of AL.
755   unsigned CC = ARMCC::AL;
756   unsigned VCC = ARMVCC::None;
757   if (ITBlock.instrInITBlock()) {
758     CC = ITBlock.getITCC();
759     ITBlock.advanceITState();
760   } else if (VPTBlock.instrInVPTBlock()) {
761     VCC = VPTBlock.getVPTPred();
762     VPTBlock.advanceVPTState();
763   }
764 
765   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
766   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
767 
768   MCInst::iterator CCI = MI.begin();
769   for (unsigned i = 0; i < NumOps; ++i, ++CCI) {
770     if (OpInfo[i].isPredicate() || CCI == MI.end()) break;
771   }
772 
773   if (ARMInsts[MI.getOpcode()].isPredicable()) {
774     CCI = MI.insert(CCI, MCOperand::createImm(CC));
775     ++CCI;
776     if (CC == ARMCC::AL)
777       MI.insert(CCI, MCOperand::createReg(0));
778     else
779       MI.insert(CCI, MCOperand::createReg(ARM::CPSR));
780   } else if (CC != ARMCC::AL) {
781     Check(S, SoftFail);
782   }
783 
784   MCInst::iterator VCCI = MI.begin();
785   unsigned VCCPos;
786   for (VCCPos = 0; VCCPos < NumOps; ++VCCPos, ++VCCI) {
787     if (ARM::isVpred(OpInfo[VCCPos].OperandType) || VCCI == MI.end()) break;
788   }
789 
790   if (isVectorPredicable(MI.getOpcode())) {
791     VCCI = MI.insert(VCCI, MCOperand::createImm(VCC));
792     ++VCCI;
793     if (VCC == ARMVCC::None)
794       MI.insert(VCCI, MCOperand::createReg(0));
795     else
796       MI.insert(VCCI, MCOperand::createReg(ARM::P0));
797     if (OpInfo[VCCPos].OperandType == ARM::OPERAND_VPRED_R) {
798       int TiedOp = ARMInsts[MI.getOpcode()].getOperandConstraint(
799         VCCPos + 2, MCOI::TIED_TO);
800       assert(TiedOp >= 0 &&
801              "Inactive register in vpred_r is not tied to an output!");
802       MI.insert(VCCI, MI.getOperand(TiedOp));
803     }
804   } else if (VCC != ARMVCC::None) {
805     Check(S, SoftFail);
806   }
807 
808   return S;
809 }
810 
811 // Thumb VFP instructions are a special case.  Because we share their
812 // encodings between ARM and Thumb modes, and they are predicable in ARM
813 // mode, the auto-generated decoder will give them an (incorrect)
814 // predicate operand.  We need to rewrite these operands based on the IT
815 // context as a post-pass.
816 void ThumbDisassembler::UpdateThumbVFPPredicate(
817   DecodeStatus &S, MCInst &MI) const {
818   unsigned CC;
819   CC = ITBlock.getITCC();
820   if (CC == 0xF)
821     CC = ARMCC::AL;
822   if (ITBlock.instrInITBlock())
823     ITBlock.advanceITState();
824   else if (VPTBlock.instrInVPTBlock()) {
825     CC = VPTBlock.getVPTPred();
826     VPTBlock.advanceVPTState();
827   }
828 
829   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
830   MCInst::iterator I = MI.begin();
831   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
832   for (unsigned i = 0; i < NumOps; ++i, ++I) {
833     if (OpInfo[i].isPredicate() ) {
834       if (CC != ARMCC::AL && !ARMInsts[MI.getOpcode()].isPredicable())
835         Check(S, SoftFail);
836       I->setImm(CC);
837       ++I;
838       if (CC == ARMCC::AL)
839         I->setReg(0);
840       else
841         I->setReg(ARM::CPSR);
842       return;
843     }
844   }
845 }
846 
847 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
848                                                ArrayRef<uint8_t> Bytes,
849                                                uint64_t Address,
850                                                raw_ostream &OS,
851                                                raw_ostream &CS) const {
852   CommentStream = &CS;
853 
854   assert(STI.getFeatureBits()[ARM::ModeThumb] &&
855          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
856 
857   // We want to read exactly 2 bytes of data.
858   if (Bytes.size() < 2) {
859     Size = 0;
860     return MCDisassembler::Fail;
861   }
862 
863   uint16_t Insn16 = (Bytes[1] << 8) | Bytes[0];
864   DecodeStatus Result =
865       decodeInstruction(DecoderTableThumb16, MI, Insn16, Address, this, STI);
866   if (Result != MCDisassembler::Fail) {
867     Size = 2;
868     Check(Result, AddThumbPredicate(MI));
869     return Result;
870   }
871 
872   Result = decodeInstruction(DecoderTableThumbSBit16, MI, Insn16, Address, this,
873                              STI);
874   if (Result) {
875     Size = 2;
876     bool InITBlock = ITBlock.instrInITBlock();
877     Check(Result, AddThumbPredicate(MI));
878     AddThumb1SBit(MI, InITBlock);
879     return Result;
880   }
881 
882   Result =
883       decodeInstruction(DecoderTableThumb216, MI, Insn16, Address, this, STI);
884   if (Result != MCDisassembler::Fail) {
885     Size = 2;
886 
887     // Nested IT blocks are UNPREDICTABLE.  Must be checked before we add
888     // the Thumb predicate.
889     if (MI.getOpcode() == ARM::t2IT && ITBlock.instrInITBlock())
890       Result = MCDisassembler::SoftFail;
891 
892     Check(Result, AddThumbPredicate(MI));
893 
894     // If we find an IT instruction, we need to parse its condition
895     // code and mask operands so that we can apply them correctly
896     // to the subsequent instructions.
897     if (MI.getOpcode() == ARM::t2IT) {
898       unsigned Firstcond = MI.getOperand(0).getImm();
899       unsigned Mask = MI.getOperand(1).getImm();
900       ITBlock.setITState(Firstcond, Mask);
901 
902       // An IT instruction that would give a 'NV' predicate is unpredictable.
903       if (Firstcond == ARMCC::AL && !isPowerOf2_32(Mask))
904         CS << "unpredictable IT predicate sequence";
905     }
906 
907     return Result;
908   }
909 
910   // We want to read exactly 4 bytes of data.
911   if (Bytes.size() < 4) {
912     Size = 0;
913     return MCDisassembler::Fail;
914   }
915 
916   uint32_t Insn32 =
917       (Bytes[3] << 8) | (Bytes[2] << 0) | (Bytes[1] << 24) | (Bytes[0] << 16);
918 
919   Result =
920       decodeInstruction(DecoderTableMVE32, MI, Insn32, Address, this, STI);
921   if (Result != MCDisassembler::Fail) {
922     Size = 4;
923 
924     // Nested VPT blocks are UNPREDICTABLE. Must be checked before we add
925     // the VPT predicate.
926     if (isVPTOpcode(MI.getOpcode()) && VPTBlock.instrInVPTBlock())
927       Result = MCDisassembler::SoftFail;
928 
929     Check(Result, AddThumbPredicate(MI));
930 
931     if (isVPTOpcode(MI.getOpcode())) {
932       unsigned Mask = MI.getOperand(0).getImm();
933       VPTBlock.setVPTState(Mask);
934     }
935 
936     return Result;
937   }
938 
939   Result =
940       decodeInstruction(DecoderTableThumb32, MI, Insn32, Address, this, STI);
941   if (Result != MCDisassembler::Fail) {
942     Size = 4;
943     bool InITBlock = ITBlock.instrInITBlock();
944     Check(Result, AddThumbPredicate(MI));
945     AddThumb1SBit(MI, InITBlock);
946     return Result;
947   }
948 
949   Result =
950       decodeInstruction(DecoderTableThumb232, MI, Insn32, Address, this, STI);
951   if (Result != MCDisassembler::Fail) {
952     Size = 4;
953     Check(Result, AddThumbPredicate(MI));
954     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn32, Result);
955   }
956 
957   if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
958     Result =
959         decodeInstruction(DecoderTableVFP32, MI, Insn32, Address, this, STI);
960     if (Result != MCDisassembler::Fail) {
961       Size = 4;
962       UpdateThumbVFPPredicate(Result, MI);
963       return Result;
964     }
965   }
966 
967   Result =
968       decodeInstruction(DecoderTableVFPV832, MI, Insn32, Address, this, STI);
969   if (Result != MCDisassembler::Fail) {
970     Size = 4;
971     return Result;
972   }
973 
974   if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
975     Result = decodeInstruction(DecoderTableNEONDup32, MI, Insn32, Address, this,
976                                STI);
977     if (Result != MCDisassembler::Fail) {
978       Size = 4;
979       Check(Result, AddThumbPredicate(MI));
980       return Result;
981     }
982   }
983 
984   if (fieldFromInstruction(Insn32, 24, 8) == 0xF9) {
985     uint32_t NEONLdStInsn = Insn32;
986     NEONLdStInsn &= 0xF0FFFFFF;
987     NEONLdStInsn |= 0x04000000;
988     Result = decodeInstruction(DecoderTableNEONLoadStore32, MI, NEONLdStInsn,
989                                Address, this, STI);
990     if (Result != MCDisassembler::Fail) {
991       Size = 4;
992       Check(Result, AddThumbPredicate(MI));
993       return Result;
994     }
995   }
996 
997   if (fieldFromInstruction(Insn32, 24, 4) == 0xF) {
998     uint32_t NEONDataInsn = Insn32;
999     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
1000     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
1001     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
1002     Result = decodeInstruction(DecoderTableNEONData32, MI, NEONDataInsn,
1003                                Address, this, STI);
1004     if (Result != MCDisassembler::Fail) {
1005       Size = 4;
1006       Check(Result, AddThumbPredicate(MI));
1007       return Result;
1008     }
1009 
1010     uint32_t NEONCryptoInsn = Insn32;
1011     NEONCryptoInsn &= 0xF0FFFFFF; // Clear bits 27-24
1012     NEONCryptoInsn |= (NEONCryptoInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
1013     NEONCryptoInsn |= 0x12000000; // Set bits 28 and 25
1014     Result = decodeInstruction(DecoderTablev8Crypto32, MI, NEONCryptoInsn,
1015                                Address, this, STI);
1016     if (Result != MCDisassembler::Fail) {
1017       Size = 4;
1018       return Result;
1019     }
1020 
1021     uint32_t NEONv8Insn = Insn32;
1022     NEONv8Insn &= 0xF3FFFFFF; // Clear bits 27-26
1023     Result = decodeInstruction(DecoderTablev8NEON32, MI, NEONv8Insn, Address,
1024                                this, STI);
1025     if (Result != MCDisassembler::Fail) {
1026       Size = 4;
1027       return Result;
1028     }
1029   }
1030 
1031   Result =
1032       decodeInstruction(DecoderTableThumb2CoProc32, MI, Insn32, Address, this, STI);
1033   if (Result != MCDisassembler::Fail) {
1034     Size = 4;
1035     Check(Result, AddThumbPredicate(MI));
1036     return Result;
1037   }
1038 
1039   Size = 0;
1040   return MCDisassembler::Fail;
1041 }
1042 
1043 extern "C" void LLVMInitializeARMDisassembler() {
1044   TargetRegistry::RegisterMCDisassembler(getTheARMLETarget(),
1045                                          createARMDisassembler);
1046   TargetRegistry::RegisterMCDisassembler(getTheARMBETarget(),
1047                                          createARMDisassembler);
1048   TargetRegistry::RegisterMCDisassembler(getTheThumbLETarget(),
1049                                          createThumbDisassembler);
1050   TargetRegistry::RegisterMCDisassembler(getTheThumbBETarget(),
1051                                          createThumbDisassembler);
1052 }
1053 
1054 static const uint16_t GPRDecoderTable[] = {
1055   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
1056   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
1057   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
1058   ARM::R12, ARM::SP, ARM::LR, ARM::PC
1059 };
1060 
1061 static const uint16_t CLRMGPRDecoderTable[] = {
1062   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
1063   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
1064   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
1065   ARM::R12, 0, ARM::LR, ARM::APSR
1066 };
1067 
1068 static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
1069                                    uint64_t Address, const void *Decoder) {
1070   if (RegNo > 15)
1071     return MCDisassembler::Fail;
1072 
1073   unsigned Register = GPRDecoderTable[RegNo];
1074   Inst.addOperand(MCOperand::createReg(Register));
1075   return MCDisassembler::Success;
1076 }
1077 
1078 static DecodeStatus DecodeCLRMGPRRegisterClass(MCInst &Inst, unsigned RegNo,
1079                                                uint64_t Address,
1080                                                const void *Decoder) {
1081   if (RegNo > 15)
1082     return MCDisassembler::Fail;
1083 
1084   unsigned Register = CLRMGPRDecoderTable[RegNo];
1085   if (Register == 0)
1086     return MCDisassembler::Fail;
1087 
1088   Inst.addOperand(MCOperand::createReg(Register));
1089   return MCDisassembler::Success;
1090 }
1091 
1092 static DecodeStatus
1093 DecodeGPRnopcRegisterClass(MCInst &Inst, unsigned RegNo,
1094                            uint64_t Address, const void *Decoder) {
1095   DecodeStatus S = MCDisassembler::Success;
1096 
1097   if (RegNo == 15)
1098     S = MCDisassembler::SoftFail;
1099 
1100   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
1101 
1102   return S;
1103 }
1104 
1105 static DecodeStatus
1106 DecodeGPRwithAPSRRegisterClass(MCInst &Inst, unsigned RegNo,
1107                                uint64_t Address, const void *Decoder) {
1108   DecodeStatus S = MCDisassembler::Success;
1109 
1110   if (RegNo == 15)
1111   {
1112     Inst.addOperand(MCOperand::createReg(ARM::APSR_NZCV));
1113     return MCDisassembler::Success;
1114   }
1115 
1116   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
1117   return S;
1118 }
1119 
1120 static DecodeStatus
1121 DecodeGPRwithZRRegisterClass(MCInst &Inst, unsigned RegNo,
1122                              uint64_t Address, const void *Decoder) {
1123   DecodeStatus S = MCDisassembler::Success;
1124 
1125   if (RegNo == 15)
1126   {
1127     Inst.addOperand(MCOperand::createReg(ARM::ZR));
1128     return MCDisassembler::Success;
1129   }
1130 
1131   if (RegNo == 13)
1132     S = MCDisassembler::SoftFail;
1133 
1134   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
1135   return S;
1136 }
1137 
1138 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
1139                                    uint64_t Address, const void *Decoder) {
1140   if (RegNo > 7)
1141     return MCDisassembler::Fail;
1142   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
1143 }
1144 
1145 static const uint16_t GPRPairDecoderTable[] = {
1146   ARM::R0_R1, ARM::R2_R3,   ARM::R4_R5,  ARM::R6_R7,
1147   ARM::R8_R9, ARM::R10_R11, ARM::R12_SP
1148 };
1149 
1150 static DecodeStatus DecodeGPRPairRegisterClass(MCInst &Inst, unsigned RegNo,
1151                                    uint64_t Address, const void *Decoder) {
1152   DecodeStatus S = MCDisassembler::Success;
1153 
1154   if (RegNo > 13)
1155     return MCDisassembler::Fail;
1156 
1157   if ((RegNo & 1) || RegNo == 0xe)
1158      S = MCDisassembler::SoftFail;
1159 
1160   unsigned RegisterPair = GPRPairDecoderTable[RegNo/2];
1161   Inst.addOperand(MCOperand::createReg(RegisterPair));
1162   return S;
1163 }
1164 
1165 static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
1166                                    uint64_t Address, const void *Decoder) {
1167   unsigned Register = 0;
1168   switch (RegNo) {
1169     case 0:
1170       Register = ARM::R0;
1171       break;
1172     case 1:
1173       Register = ARM::R1;
1174       break;
1175     case 2:
1176       Register = ARM::R2;
1177       break;
1178     case 3:
1179       Register = ARM::R3;
1180       break;
1181     case 9:
1182       Register = ARM::R9;
1183       break;
1184     case 12:
1185       Register = ARM::R12;
1186       break;
1187     default:
1188       return MCDisassembler::Fail;
1189     }
1190 
1191   Inst.addOperand(MCOperand::createReg(Register));
1192   return MCDisassembler::Success;
1193 }
1194 
1195 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
1196                                    uint64_t Address, const void *Decoder) {
1197   DecodeStatus S = MCDisassembler::Success;
1198 
1199   const FeatureBitset &featureBits =
1200     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
1201 
1202   if ((RegNo == 13 && !featureBits[ARM::HasV8Ops]) || RegNo == 15)
1203     S = MCDisassembler::SoftFail;
1204 
1205   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
1206   return S;
1207 }
1208 
1209 static const uint16_t SPRDecoderTable[] = {
1210      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
1211      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
1212      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
1213     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
1214     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
1215     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
1216     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
1217     ARM::S28, ARM::S29, ARM::S30, ARM::S31
1218 };
1219 
1220 static DecodeStatus DecodeSPRRegisterClass(MCInst &Inst, unsigned RegNo,
1221                                    uint64_t Address, const void *Decoder) {
1222   if (RegNo > 31)
1223     return MCDisassembler::Fail;
1224 
1225   unsigned Register = SPRDecoderTable[RegNo];
1226   Inst.addOperand(MCOperand::createReg(Register));
1227   return MCDisassembler::Success;
1228 }
1229 
1230 static DecodeStatus DecodeHPRRegisterClass(MCInst &Inst, unsigned RegNo,
1231                                    uint64_t Address, const void *Decoder) {
1232   return DecodeSPRRegisterClass(Inst, RegNo, Address, Decoder);
1233 }
1234 
1235 static const uint16_t DPRDecoderTable[] = {
1236      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
1237      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
1238      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
1239     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
1240     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
1241     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
1242     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
1243     ARM::D28, ARM::D29, ARM::D30, ARM::D31
1244 };
1245 
1246 static DecodeStatus DecodeDPRRegisterClass(MCInst &Inst, unsigned RegNo,
1247                                    uint64_t Address, const void *Decoder) {
1248   const FeatureBitset &featureBits =
1249     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
1250 
1251   bool hasD32 = featureBits[ARM::FeatureD32];
1252 
1253   if (RegNo > 31 || (!hasD32 && RegNo > 15))
1254     return MCDisassembler::Fail;
1255 
1256   unsigned Register = DPRDecoderTable[RegNo];
1257   Inst.addOperand(MCOperand::createReg(Register));
1258   return MCDisassembler::Success;
1259 }
1260 
1261 static DecodeStatus DecodeDPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
1262                                    uint64_t Address, const void *Decoder) {
1263   if (RegNo > 7)
1264     return MCDisassembler::Fail;
1265   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
1266 }
1267 
1268 static DecodeStatus DecodeSPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
1269                                    uint64_t Address, const void *Decoder) {
1270   if (RegNo > 15)
1271     return MCDisassembler::Fail;
1272   return DecodeSPRRegisterClass(Inst, RegNo, Address, Decoder);
1273 }
1274 
1275 static DecodeStatus
1276 DecodeDPR_VFP2RegisterClass(MCInst &Inst, unsigned RegNo,
1277                             uint64_t Address, const void *Decoder) {
1278   if (RegNo > 15)
1279     return MCDisassembler::Fail;
1280   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
1281 }
1282 
1283 static const uint16_t QPRDecoderTable[] = {
1284      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
1285      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
1286      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
1287     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
1288 };
1289 
1290 static DecodeStatus DecodeQPRRegisterClass(MCInst &Inst, unsigned RegNo,
1291                                    uint64_t Address, const void *Decoder) {
1292   if (RegNo > 31 || (RegNo & 1) != 0)
1293     return MCDisassembler::Fail;
1294   RegNo >>= 1;
1295 
1296   unsigned Register = QPRDecoderTable[RegNo];
1297   Inst.addOperand(MCOperand::createReg(Register));
1298   return MCDisassembler::Success;
1299 }
1300 
1301 static const uint16_t DPairDecoderTable[] = {
1302   ARM::Q0,  ARM::D1_D2,   ARM::Q1,  ARM::D3_D4,   ARM::Q2,  ARM::D5_D6,
1303   ARM::Q3,  ARM::D7_D8,   ARM::Q4,  ARM::D9_D10,  ARM::Q5,  ARM::D11_D12,
1304   ARM::Q6,  ARM::D13_D14, ARM::Q7,  ARM::D15_D16, ARM::Q8,  ARM::D17_D18,
1305   ARM::Q9,  ARM::D19_D20, ARM::Q10, ARM::D21_D22, ARM::Q11, ARM::D23_D24,
1306   ARM::Q12, ARM::D25_D26, ARM::Q13, ARM::D27_D28, ARM::Q14, ARM::D29_D30,
1307   ARM::Q15
1308 };
1309 
1310 static DecodeStatus DecodeDPairRegisterClass(MCInst &Inst, unsigned RegNo,
1311                                    uint64_t Address, const void *Decoder) {
1312   if (RegNo > 30)
1313     return MCDisassembler::Fail;
1314 
1315   unsigned Register = DPairDecoderTable[RegNo];
1316   Inst.addOperand(MCOperand::createReg(Register));
1317   return MCDisassembler::Success;
1318 }
1319 
1320 static const uint16_t DPairSpacedDecoderTable[] = {
1321   ARM::D0_D2,   ARM::D1_D3,   ARM::D2_D4,   ARM::D3_D5,
1322   ARM::D4_D6,   ARM::D5_D7,   ARM::D6_D8,   ARM::D7_D9,
1323   ARM::D8_D10,  ARM::D9_D11,  ARM::D10_D12, ARM::D11_D13,
1324   ARM::D12_D14, ARM::D13_D15, ARM::D14_D16, ARM::D15_D17,
1325   ARM::D16_D18, ARM::D17_D19, ARM::D18_D20, ARM::D19_D21,
1326   ARM::D20_D22, ARM::D21_D23, ARM::D22_D24, ARM::D23_D25,
1327   ARM::D24_D26, ARM::D25_D27, ARM::D26_D28, ARM::D27_D29,
1328   ARM::D28_D30, ARM::D29_D31
1329 };
1330 
1331 static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst &Inst,
1332                                                    unsigned RegNo,
1333                                                    uint64_t Address,
1334                                                    const void *Decoder) {
1335   if (RegNo > 29)
1336     return MCDisassembler::Fail;
1337 
1338   unsigned Register = DPairSpacedDecoderTable[RegNo];
1339   Inst.addOperand(MCOperand::createReg(Register));
1340   return MCDisassembler::Success;
1341 }
1342 
1343 static DecodeStatus DecodePredicateOperand(MCInst &Inst, unsigned Val,
1344                                uint64_t Address, const void *Decoder) {
1345   DecodeStatus S = MCDisassembler::Success;
1346   if (Val == 0xF) return MCDisassembler::Fail;
1347   // AL predicate is not allowed on Thumb1 branches.
1348   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
1349     return MCDisassembler::Fail;
1350   if (Val != ARMCC::AL && !ARMInsts[Inst.getOpcode()].isPredicable())
1351     Check(S, MCDisassembler::SoftFail);
1352   Inst.addOperand(MCOperand::createImm(Val));
1353   if (Val == ARMCC::AL) {
1354     Inst.addOperand(MCOperand::createReg(0));
1355   } else
1356     Inst.addOperand(MCOperand::createReg(ARM::CPSR));
1357   return S;
1358 }
1359 
1360 static DecodeStatus DecodeCCOutOperand(MCInst &Inst, unsigned Val,
1361                                uint64_t Address, const void *Decoder) {
1362   if (Val)
1363     Inst.addOperand(MCOperand::createReg(ARM::CPSR));
1364   else
1365     Inst.addOperand(MCOperand::createReg(0));
1366   return MCDisassembler::Success;
1367 }
1368 
1369 static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Val,
1370                                uint64_t Address, const void *Decoder) {
1371   DecodeStatus S = MCDisassembler::Success;
1372 
1373   unsigned Rm = fieldFromInstruction(Val, 0, 4);
1374   unsigned type = fieldFromInstruction(Val, 5, 2);
1375   unsigned imm = fieldFromInstruction(Val, 7, 5);
1376 
1377   // Register-immediate
1378   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
1379     return MCDisassembler::Fail;
1380 
1381   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1382   switch (type) {
1383     case 0:
1384       Shift = ARM_AM::lsl;
1385       break;
1386     case 1:
1387       Shift = ARM_AM::lsr;
1388       break;
1389     case 2:
1390       Shift = ARM_AM::asr;
1391       break;
1392     case 3:
1393       Shift = ARM_AM::ror;
1394       break;
1395   }
1396 
1397   if (Shift == ARM_AM::ror && imm == 0)
1398     Shift = ARM_AM::rrx;
1399 
1400   unsigned Op = Shift | (imm << 3);
1401   Inst.addOperand(MCOperand::createImm(Op));
1402 
1403   return S;
1404 }
1405 
1406 static DecodeStatus DecodeSORegRegOperand(MCInst &Inst, unsigned Val,
1407                                uint64_t Address, const void *Decoder) {
1408   DecodeStatus S = MCDisassembler::Success;
1409 
1410   unsigned Rm = fieldFromInstruction(Val, 0, 4);
1411   unsigned type = fieldFromInstruction(Val, 5, 2);
1412   unsigned Rs = fieldFromInstruction(Val, 8, 4);
1413 
1414   // Register-register
1415   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1416     return MCDisassembler::Fail;
1417   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
1418     return MCDisassembler::Fail;
1419 
1420   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1421   switch (type) {
1422     case 0:
1423       Shift = ARM_AM::lsl;
1424       break;
1425     case 1:
1426       Shift = ARM_AM::lsr;
1427       break;
1428     case 2:
1429       Shift = ARM_AM::asr;
1430       break;
1431     case 3:
1432       Shift = ARM_AM::ror;
1433       break;
1434   }
1435 
1436   Inst.addOperand(MCOperand::createImm(Shift));
1437 
1438   return S;
1439 }
1440 
1441 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
1442                                  uint64_t Address, const void *Decoder) {
1443   DecodeStatus S = MCDisassembler::Success;
1444 
1445   bool NeedDisjointWriteback = false;
1446   unsigned WritebackReg = 0;
1447   bool CLRM = false;
1448   switch (Inst.getOpcode()) {
1449   default:
1450     break;
1451   case ARM::LDMIA_UPD:
1452   case ARM::LDMDB_UPD:
1453   case ARM::LDMIB_UPD:
1454   case ARM::LDMDA_UPD:
1455   case ARM::t2LDMIA_UPD:
1456   case ARM::t2LDMDB_UPD:
1457   case ARM::t2STMIA_UPD:
1458   case ARM::t2STMDB_UPD:
1459     NeedDisjointWriteback = true;
1460     WritebackReg = Inst.getOperand(0).getReg();
1461     break;
1462   case ARM::t2CLRM:
1463     CLRM = true;
1464     break;
1465   }
1466 
1467   // Empty register lists are not allowed.
1468   if (Val == 0) return MCDisassembler::Fail;
1469   for (unsigned i = 0; i < 16; ++i) {
1470     if (Val & (1 << i)) {
1471       if (CLRM) {
1472         if (!Check(S, DecodeCLRMGPRRegisterClass(Inst, i, Address, Decoder))) {
1473           return MCDisassembler::Fail;
1474         }
1475       } else {
1476         if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
1477           return MCDisassembler::Fail;
1478         // Writeback not allowed if Rn is in the target list.
1479         if (NeedDisjointWriteback && WritebackReg == Inst.end()[-1].getReg())
1480           Check(S, MCDisassembler::SoftFail);
1481       }
1482     }
1483   }
1484 
1485   return S;
1486 }
1487 
1488 static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
1489                                  uint64_t Address, const void *Decoder) {
1490   DecodeStatus S = MCDisassembler::Success;
1491 
1492   unsigned Vd = fieldFromInstruction(Val, 8, 5);
1493   unsigned regs = fieldFromInstruction(Val, 0, 8);
1494 
1495   // In case of unpredictable encoding, tweak the operands.
1496   if (regs == 0 || (Vd + regs) > 32) {
1497     regs = Vd + regs > 32 ? 32 - Vd : regs;
1498     regs = std::max( 1u, regs);
1499     S = MCDisassembler::SoftFail;
1500   }
1501 
1502   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
1503     return MCDisassembler::Fail;
1504   for (unsigned i = 0; i < (regs - 1); ++i) {
1505     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1506       return MCDisassembler::Fail;
1507   }
1508 
1509   return S;
1510 }
1511 
1512 static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
1513                                  uint64_t Address, const void *Decoder) {
1514   DecodeStatus S = MCDisassembler::Success;
1515 
1516   unsigned Vd = fieldFromInstruction(Val, 8, 5);
1517   unsigned regs = fieldFromInstruction(Val, 1, 7);
1518 
1519   // In case of unpredictable encoding, tweak the operands.
1520   if (regs == 0 || regs > 16 || (Vd + regs) > 32) {
1521     regs = Vd + regs > 32 ? 32 - Vd : regs;
1522     regs = std::max( 1u, regs);
1523     regs = std::min(16u, regs);
1524     S = MCDisassembler::SoftFail;
1525   }
1526 
1527   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
1528       return MCDisassembler::Fail;
1529   for (unsigned i = 0; i < (regs - 1); ++i) {
1530     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1531       return MCDisassembler::Fail;
1532   }
1533 
1534   return S;
1535 }
1536 
1537 static DecodeStatus DecodeBitfieldMaskOperand(MCInst &Inst, unsigned Val,
1538                                       uint64_t Address, const void *Decoder) {
1539   // This operand encodes a mask of contiguous zeros between a specified MSB
1540   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
1541   // the mask of all bits LSB-and-lower, and then xor them to create
1542   // the mask of that's all ones on [msb, lsb].  Finally we not it to
1543   // create the final mask.
1544   unsigned msb = fieldFromInstruction(Val, 5, 5);
1545   unsigned lsb = fieldFromInstruction(Val, 0, 5);
1546 
1547   DecodeStatus S = MCDisassembler::Success;
1548   if (lsb > msb) {
1549     Check(S, MCDisassembler::SoftFail);
1550     // The check above will cause the warning for the "potentially undefined
1551     // instruction encoding" but we can't build a bad MCOperand value here
1552     // with a lsb > msb or else printing the MCInst will cause a crash.
1553     lsb = msb;
1554   }
1555 
1556   uint32_t msb_mask = 0xFFFFFFFF;
1557   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;
1558   uint32_t lsb_mask = (1U << lsb) - 1;
1559 
1560   Inst.addOperand(MCOperand::createImm(~(msb_mask ^ lsb_mask)));
1561   return S;
1562 }
1563 
1564 static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
1565                                   uint64_t Address, const void *Decoder) {
1566   DecodeStatus S = MCDisassembler::Success;
1567 
1568   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1569   unsigned CRd = fieldFromInstruction(Insn, 12, 4);
1570   unsigned coproc = fieldFromInstruction(Insn, 8, 4);
1571   unsigned imm = fieldFromInstruction(Insn, 0, 8);
1572   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1573   unsigned U = fieldFromInstruction(Insn, 23, 1);
1574   const FeatureBitset &featureBits =
1575     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
1576 
1577   switch (Inst.getOpcode()) {
1578     case ARM::LDC_OFFSET:
1579     case ARM::LDC_PRE:
1580     case ARM::LDC_POST:
1581     case ARM::LDC_OPTION:
1582     case ARM::LDCL_OFFSET:
1583     case ARM::LDCL_PRE:
1584     case ARM::LDCL_POST:
1585     case ARM::LDCL_OPTION:
1586     case ARM::STC_OFFSET:
1587     case ARM::STC_PRE:
1588     case ARM::STC_POST:
1589     case ARM::STC_OPTION:
1590     case ARM::STCL_OFFSET:
1591     case ARM::STCL_PRE:
1592     case ARM::STCL_POST:
1593     case ARM::STCL_OPTION:
1594     case ARM::t2LDC_OFFSET:
1595     case ARM::t2LDC_PRE:
1596     case ARM::t2LDC_POST:
1597     case ARM::t2LDC_OPTION:
1598     case ARM::t2LDCL_OFFSET:
1599     case ARM::t2LDCL_PRE:
1600     case ARM::t2LDCL_POST:
1601     case ARM::t2LDCL_OPTION:
1602     case ARM::t2STC_OFFSET:
1603     case ARM::t2STC_PRE:
1604     case ARM::t2STC_POST:
1605     case ARM::t2STC_OPTION:
1606     case ARM::t2STCL_OFFSET:
1607     case ARM::t2STCL_PRE:
1608     case ARM::t2STCL_POST:
1609     case ARM::t2STCL_OPTION:
1610     case ARM::t2LDC2_OFFSET:
1611     case ARM::t2LDC2L_OFFSET:
1612     case ARM::t2LDC2_PRE:
1613     case ARM::t2LDC2L_PRE:
1614     case ARM::t2STC2_OFFSET:
1615     case ARM::t2STC2L_OFFSET:
1616     case ARM::t2STC2_PRE:
1617     case ARM::t2STC2L_PRE:
1618     case ARM::LDC2_OFFSET:
1619     case ARM::LDC2L_OFFSET:
1620     case ARM::LDC2_PRE:
1621     case ARM::LDC2L_PRE:
1622     case ARM::STC2_OFFSET:
1623     case ARM::STC2L_OFFSET:
1624     case ARM::STC2_PRE:
1625     case ARM::STC2L_PRE:
1626     case ARM::t2LDC2_OPTION:
1627     case ARM::t2STC2_OPTION:
1628     case ARM::t2LDC2_POST:
1629     case ARM::t2LDC2L_POST:
1630     case ARM::t2STC2_POST:
1631     case ARM::t2STC2L_POST:
1632     case ARM::LDC2_POST:
1633     case ARM::LDC2L_POST:
1634     case ARM::STC2_POST:
1635     case ARM::STC2L_POST:
1636       if (coproc == 0xA || coproc == 0xB ||
1637           (featureBits[ARM::HasV8_1MMainlineOps] &&
1638            (coproc == 0x8 || coproc == 0x9 || coproc == 0xA || coproc == 0xB ||
1639             coproc == 0xE || coproc == 0xF)))
1640         return MCDisassembler::Fail;
1641       break;
1642     default:
1643       break;
1644   }
1645 
1646   if (featureBits[ARM::HasV8Ops] && (coproc != 14))
1647     return MCDisassembler::Fail;
1648 
1649   Inst.addOperand(MCOperand::createImm(coproc));
1650   Inst.addOperand(MCOperand::createImm(CRd));
1651   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1652     return MCDisassembler::Fail;
1653 
1654   switch (Inst.getOpcode()) {
1655     case ARM::t2LDC2_OFFSET:
1656     case ARM::t2LDC2L_OFFSET:
1657     case ARM::t2LDC2_PRE:
1658     case ARM::t2LDC2L_PRE:
1659     case ARM::t2STC2_OFFSET:
1660     case ARM::t2STC2L_OFFSET:
1661     case ARM::t2STC2_PRE:
1662     case ARM::t2STC2L_PRE:
1663     case ARM::LDC2_OFFSET:
1664     case ARM::LDC2L_OFFSET:
1665     case ARM::LDC2_PRE:
1666     case ARM::LDC2L_PRE:
1667     case ARM::STC2_OFFSET:
1668     case ARM::STC2L_OFFSET:
1669     case ARM::STC2_PRE:
1670     case ARM::STC2L_PRE:
1671     case ARM::t2LDC_OFFSET:
1672     case ARM::t2LDCL_OFFSET:
1673     case ARM::t2LDC_PRE:
1674     case ARM::t2LDCL_PRE:
1675     case ARM::t2STC_OFFSET:
1676     case ARM::t2STCL_OFFSET:
1677     case ARM::t2STC_PRE:
1678     case ARM::t2STCL_PRE:
1679     case ARM::LDC_OFFSET:
1680     case ARM::LDCL_OFFSET:
1681     case ARM::LDC_PRE:
1682     case ARM::LDCL_PRE:
1683     case ARM::STC_OFFSET:
1684     case ARM::STCL_OFFSET:
1685     case ARM::STC_PRE:
1686     case ARM::STCL_PRE:
1687       imm = ARM_AM::getAM5Opc(U ? ARM_AM::add : ARM_AM::sub, imm);
1688       Inst.addOperand(MCOperand::createImm(imm));
1689       break;
1690     case ARM::t2LDC2_POST:
1691     case ARM::t2LDC2L_POST:
1692     case ARM::t2STC2_POST:
1693     case ARM::t2STC2L_POST:
1694     case ARM::LDC2_POST:
1695     case ARM::LDC2L_POST:
1696     case ARM::STC2_POST:
1697     case ARM::STC2L_POST:
1698     case ARM::t2LDC_POST:
1699     case ARM::t2LDCL_POST:
1700     case ARM::t2STC_POST:
1701     case ARM::t2STCL_POST:
1702     case ARM::LDC_POST:
1703     case ARM::LDCL_POST:
1704     case ARM::STC_POST:
1705     case ARM::STCL_POST:
1706       imm |= U << 8;
1707       LLVM_FALLTHROUGH;
1708     default:
1709       // The 'option' variant doesn't encode 'U' in the immediate since
1710       // the immediate is unsigned [0,255].
1711       Inst.addOperand(MCOperand::createImm(imm));
1712       break;
1713   }
1714 
1715   switch (Inst.getOpcode()) {
1716     case ARM::LDC_OFFSET:
1717     case ARM::LDC_PRE:
1718     case ARM::LDC_POST:
1719     case ARM::LDC_OPTION:
1720     case ARM::LDCL_OFFSET:
1721     case ARM::LDCL_PRE:
1722     case ARM::LDCL_POST:
1723     case ARM::LDCL_OPTION:
1724     case ARM::STC_OFFSET:
1725     case ARM::STC_PRE:
1726     case ARM::STC_POST:
1727     case ARM::STC_OPTION:
1728     case ARM::STCL_OFFSET:
1729     case ARM::STCL_PRE:
1730     case ARM::STCL_POST:
1731     case ARM::STCL_OPTION:
1732       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1733         return MCDisassembler::Fail;
1734       break;
1735     default:
1736       break;
1737   }
1738 
1739   return S;
1740 }
1741 
1742 static DecodeStatus
1743 DecodeAddrMode2IdxInstruction(MCInst &Inst, unsigned Insn,
1744                               uint64_t Address, const void *Decoder) {
1745   DecodeStatus S = MCDisassembler::Success;
1746 
1747   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1748   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
1749   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1750   unsigned imm = fieldFromInstruction(Insn, 0, 12);
1751   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1752   unsigned reg = fieldFromInstruction(Insn, 25, 1);
1753   unsigned P = fieldFromInstruction(Insn, 24, 1);
1754   unsigned W = fieldFromInstruction(Insn, 21, 1);
1755 
1756   // On stores, the writeback operand precedes Rt.
1757   switch (Inst.getOpcode()) {
1758     case ARM::STR_POST_IMM:
1759     case ARM::STR_POST_REG:
1760     case ARM::STRB_POST_IMM:
1761     case ARM::STRB_POST_REG:
1762     case ARM::STRT_POST_REG:
1763     case ARM::STRT_POST_IMM:
1764     case ARM::STRBT_POST_REG:
1765     case ARM::STRBT_POST_IMM:
1766       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1767         return MCDisassembler::Fail;
1768       break;
1769     default:
1770       break;
1771   }
1772 
1773   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1774     return MCDisassembler::Fail;
1775 
1776   // On loads, the writeback operand comes after Rt.
1777   switch (Inst.getOpcode()) {
1778     case ARM::LDR_POST_IMM:
1779     case ARM::LDR_POST_REG:
1780     case ARM::LDRB_POST_IMM:
1781     case ARM::LDRB_POST_REG:
1782     case ARM::LDRBT_POST_REG:
1783     case ARM::LDRBT_POST_IMM:
1784     case ARM::LDRT_POST_REG:
1785     case ARM::LDRT_POST_IMM:
1786       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1787         return MCDisassembler::Fail;
1788       break;
1789     default:
1790       break;
1791   }
1792 
1793   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1794     return MCDisassembler::Fail;
1795 
1796   ARM_AM::AddrOpc Op = ARM_AM::add;
1797   if (!fieldFromInstruction(Insn, 23, 1))
1798     Op = ARM_AM::sub;
1799 
1800   bool writeback = (P == 0) || (W == 1);
1801   unsigned idx_mode = 0;
1802   if (P && writeback)
1803     idx_mode = ARMII::IndexModePre;
1804   else if (!P && writeback)
1805     idx_mode = ARMII::IndexModePost;
1806 
1807   if (writeback && (Rn == 15 || Rn == Rt))
1808     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1809 
1810   if (reg) {
1811     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1812       return MCDisassembler::Fail;
1813     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1814     switch( fieldFromInstruction(Insn, 5, 2)) {
1815       case 0:
1816         Opc = ARM_AM::lsl;
1817         break;
1818       case 1:
1819         Opc = ARM_AM::lsr;
1820         break;
1821       case 2:
1822         Opc = ARM_AM::asr;
1823         break;
1824       case 3:
1825         Opc = ARM_AM::ror;
1826         break;
1827       default:
1828         return MCDisassembler::Fail;
1829     }
1830     unsigned amt = fieldFromInstruction(Insn, 7, 5);
1831     if (Opc == ARM_AM::ror && amt == 0)
1832       Opc = ARM_AM::rrx;
1833     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1834 
1835     Inst.addOperand(MCOperand::createImm(imm));
1836   } else {
1837     Inst.addOperand(MCOperand::createReg(0));
1838     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1839     Inst.addOperand(MCOperand::createImm(tmp));
1840   }
1841 
1842   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1843     return MCDisassembler::Fail;
1844 
1845   return S;
1846 }
1847 
1848 static DecodeStatus DecodeSORegMemOperand(MCInst &Inst, unsigned Val,
1849                                   uint64_t Address, const void *Decoder) {
1850   DecodeStatus S = MCDisassembler::Success;
1851 
1852   unsigned Rn = fieldFromInstruction(Val, 13, 4);
1853   unsigned Rm = fieldFromInstruction(Val,  0, 4);
1854   unsigned type = fieldFromInstruction(Val, 5, 2);
1855   unsigned imm = fieldFromInstruction(Val, 7, 5);
1856   unsigned U = fieldFromInstruction(Val, 12, 1);
1857 
1858   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1859   switch (type) {
1860     case 0:
1861       ShOp = ARM_AM::lsl;
1862       break;
1863     case 1:
1864       ShOp = ARM_AM::lsr;
1865       break;
1866     case 2:
1867       ShOp = ARM_AM::asr;
1868       break;
1869     case 3:
1870       ShOp = ARM_AM::ror;
1871       break;
1872   }
1873 
1874   if (ShOp == ARM_AM::ror && imm == 0)
1875     ShOp = ARM_AM::rrx;
1876 
1877   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1878     return MCDisassembler::Fail;
1879   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1880     return MCDisassembler::Fail;
1881   unsigned shift;
1882   if (U)
1883     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1884   else
1885     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1886   Inst.addOperand(MCOperand::createImm(shift));
1887 
1888   return S;
1889 }
1890 
1891 static DecodeStatus
1892 DecodeAddrMode3Instruction(MCInst &Inst, unsigned Insn,
1893                            uint64_t Address, const void *Decoder) {
1894   DecodeStatus S = MCDisassembler::Success;
1895 
1896   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
1897   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1898   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1899   unsigned type = fieldFromInstruction(Insn, 22, 1);
1900   unsigned imm = fieldFromInstruction(Insn, 8, 4);
1901   unsigned U = ((~fieldFromInstruction(Insn, 23, 1)) & 1) << 8;
1902   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1903   unsigned W = fieldFromInstruction(Insn, 21, 1);
1904   unsigned P = fieldFromInstruction(Insn, 24, 1);
1905   unsigned Rt2 = Rt + 1;
1906 
1907   bool writeback = (W == 1) | (P == 0);
1908 
1909   // For {LD,ST}RD, Rt must be even, else undefined.
1910   switch (Inst.getOpcode()) {
1911     case ARM::STRD:
1912     case ARM::STRD_PRE:
1913     case ARM::STRD_POST:
1914     case ARM::LDRD:
1915     case ARM::LDRD_PRE:
1916     case ARM::LDRD_POST:
1917       if (Rt & 0x1) S = MCDisassembler::SoftFail;
1918       break;
1919     default:
1920       break;
1921   }
1922   switch (Inst.getOpcode()) {
1923     case ARM::STRD:
1924     case ARM::STRD_PRE:
1925     case ARM::STRD_POST:
1926       if (P == 0 && W == 1)
1927         S = MCDisassembler::SoftFail;
1928 
1929       if (writeback && (Rn == 15 || Rn == Rt || Rn == Rt2))
1930         S = MCDisassembler::SoftFail;
1931       if (type && Rm == 15)
1932         S = MCDisassembler::SoftFail;
1933       if (Rt2 == 15)
1934         S = MCDisassembler::SoftFail;
1935       if (!type && fieldFromInstruction(Insn, 8, 4))
1936         S = MCDisassembler::SoftFail;
1937       break;
1938     case ARM::STRH:
1939     case ARM::STRH_PRE:
1940     case ARM::STRH_POST:
1941       if (Rt == 15)
1942         S = MCDisassembler::SoftFail;
1943       if (writeback && (Rn == 15 || Rn == Rt))
1944         S = MCDisassembler::SoftFail;
1945       if (!type && Rm == 15)
1946         S = MCDisassembler::SoftFail;
1947       break;
1948     case ARM::LDRD:
1949     case ARM::LDRD_PRE:
1950     case ARM::LDRD_POST:
1951       if (type && Rn == 15) {
1952         if (Rt2 == 15)
1953           S = MCDisassembler::SoftFail;
1954         break;
1955       }
1956       if (P == 0 && W == 1)
1957         S = MCDisassembler::SoftFail;
1958       if (!type && (Rt2 == 15 || Rm == 15 || Rm == Rt || Rm == Rt2))
1959         S = MCDisassembler::SoftFail;
1960       if (!type && writeback && Rn == 15)
1961         S = MCDisassembler::SoftFail;
1962       if (writeback && (Rn == Rt || Rn == Rt2))
1963         S = MCDisassembler::SoftFail;
1964       break;
1965     case ARM::LDRH:
1966     case ARM::LDRH_PRE:
1967     case ARM::LDRH_POST:
1968       if (type && Rn == 15) {
1969         if (Rt == 15)
1970           S = MCDisassembler::SoftFail;
1971         break;
1972       }
1973       if (Rt == 15)
1974         S = MCDisassembler::SoftFail;
1975       if (!type && Rm == 15)
1976         S = MCDisassembler::SoftFail;
1977       if (!type && writeback && (Rn == 15 || Rn == Rt))
1978         S = MCDisassembler::SoftFail;
1979       break;
1980     case ARM::LDRSH:
1981     case ARM::LDRSH_PRE:
1982     case ARM::LDRSH_POST:
1983     case ARM::LDRSB:
1984     case ARM::LDRSB_PRE:
1985     case ARM::LDRSB_POST:
1986       if (type && Rn == 15) {
1987         if (Rt == 15)
1988           S = MCDisassembler::SoftFail;
1989         break;
1990       }
1991       if (type && (Rt == 15 || (writeback && Rn == Rt)))
1992         S = MCDisassembler::SoftFail;
1993       if (!type && (Rt == 15 || Rm == 15))
1994         S = MCDisassembler::SoftFail;
1995       if (!type && writeback && (Rn == 15 || Rn == Rt))
1996         S = MCDisassembler::SoftFail;
1997       break;
1998     default:
1999       break;
2000   }
2001 
2002   if (writeback) { // Writeback
2003     if (P)
2004       U |= ARMII::IndexModePre << 9;
2005     else
2006       U |= ARMII::IndexModePost << 9;
2007 
2008     // On stores, the writeback operand precedes Rt.
2009     switch (Inst.getOpcode()) {
2010     case ARM::STRD:
2011     case ARM::STRD_PRE:
2012     case ARM::STRD_POST:
2013     case ARM::STRH:
2014     case ARM::STRH_PRE:
2015     case ARM::STRH_POST:
2016       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2017         return MCDisassembler::Fail;
2018       break;
2019     default:
2020       break;
2021     }
2022   }
2023 
2024   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2025     return MCDisassembler::Fail;
2026   switch (Inst.getOpcode()) {
2027     case ARM::STRD:
2028     case ARM::STRD_PRE:
2029     case ARM::STRD_POST:
2030     case ARM::LDRD:
2031     case ARM::LDRD_PRE:
2032     case ARM::LDRD_POST:
2033       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
2034         return MCDisassembler::Fail;
2035       break;
2036     default:
2037       break;
2038   }
2039 
2040   if (writeback) {
2041     // On loads, the writeback operand comes after Rt.
2042     switch (Inst.getOpcode()) {
2043     case ARM::LDRD:
2044     case ARM::LDRD_PRE:
2045     case ARM::LDRD_POST:
2046     case ARM::LDRH:
2047     case ARM::LDRH_PRE:
2048     case ARM::LDRH_POST:
2049     case ARM::LDRSH:
2050     case ARM::LDRSH_PRE:
2051     case ARM::LDRSH_POST:
2052     case ARM::LDRSB:
2053     case ARM::LDRSB_PRE:
2054     case ARM::LDRSB_POST:
2055     case ARM::LDRHTr:
2056     case ARM::LDRSBTr:
2057       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2058         return MCDisassembler::Fail;
2059       break;
2060     default:
2061       break;
2062     }
2063   }
2064 
2065   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2066     return MCDisassembler::Fail;
2067 
2068   if (type) {
2069     Inst.addOperand(MCOperand::createReg(0));
2070     Inst.addOperand(MCOperand::createImm(U | (imm << 4) | Rm));
2071   } else {
2072     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2073     return MCDisassembler::Fail;
2074     Inst.addOperand(MCOperand::createImm(U));
2075   }
2076 
2077   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2078     return MCDisassembler::Fail;
2079 
2080   return S;
2081 }
2082 
2083 static DecodeStatus DecodeRFEInstruction(MCInst &Inst, unsigned Insn,
2084                                  uint64_t Address, const void *Decoder) {
2085   DecodeStatus S = MCDisassembler::Success;
2086 
2087   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2088   unsigned mode = fieldFromInstruction(Insn, 23, 2);
2089 
2090   switch (mode) {
2091     case 0:
2092       mode = ARM_AM::da;
2093       break;
2094     case 1:
2095       mode = ARM_AM::ia;
2096       break;
2097     case 2:
2098       mode = ARM_AM::db;
2099       break;
2100     case 3:
2101       mode = ARM_AM::ib;
2102       break;
2103   }
2104 
2105   Inst.addOperand(MCOperand::createImm(mode));
2106   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2107     return MCDisassembler::Fail;
2108 
2109   return S;
2110 }
2111 
2112 static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
2113                                uint64_t Address, const void *Decoder) {
2114   DecodeStatus S = MCDisassembler::Success;
2115 
2116   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2117   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2118   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2119   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2120 
2121   if (pred == 0xF)
2122     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
2123 
2124   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2125     return MCDisassembler::Fail;
2126   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
2127     return MCDisassembler::Fail;
2128   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2129     return MCDisassembler::Fail;
2130   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2131     return MCDisassembler::Fail;
2132   return S;
2133 }
2134 
2135 static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst &Inst,
2136                                   unsigned Insn,
2137                                   uint64_t Address, const void *Decoder) {
2138   DecodeStatus S = MCDisassembler::Success;
2139 
2140   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2141   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2142   unsigned reglist = fieldFromInstruction(Insn, 0, 16);
2143 
2144   if (pred == 0xF) {
2145     // Ambiguous with RFE and SRS
2146     switch (Inst.getOpcode()) {
2147       case ARM::LDMDA:
2148         Inst.setOpcode(ARM::RFEDA);
2149         break;
2150       case ARM::LDMDA_UPD:
2151         Inst.setOpcode(ARM::RFEDA_UPD);
2152         break;
2153       case ARM::LDMDB:
2154         Inst.setOpcode(ARM::RFEDB);
2155         break;
2156       case ARM::LDMDB_UPD:
2157         Inst.setOpcode(ARM::RFEDB_UPD);
2158         break;
2159       case ARM::LDMIA:
2160         Inst.setOpcode(ARM::RFEIA);
2161         break;
2162       case ARM::LDMIA_UPD:
2163         Inst.setOpcode(ARM::RFEIA_UPD);
2164         break;
2165       case ARM::LDMIB:
2166         Inst.setOpcode(ARM::RFEIB);
2167         break;
2168       case ARM::LDMIB_UPD:
2169         Inst.setOpcode(ARM::RFEIB_UPD);
2170         break;
2171       case ARM::STMDA:
2172         Inst.setOpcode(ARM::SRSDA);
2173         break;
2174       case ARM::STMDA_UPD:
2175         Inst.setOpcode(ARM::SRSDA_UPD);
2176         break;
2177       case ARM::STMDB:
2178         Inst.setOpcode(ARM::SRSDB);
2179         break;
2180       case ARM::STMDB_UPD:
2181         Inst.setOpcode(ARM::SRSDB_UPD);
2182         break;
2183       case ARM::STMIA:
2184         Inst.setOpcode(ARM::SRSIA);
2185         break;
2186       case ARM::STMIA_UPD:
2187         Inst.setOpcode(ARM::SRSIA_UPD);
2188         break;
2189       case ARM::STMIB:
2190         Inst.setOpcode(ARM::SRSIB);
2191         break;
2192       case ARM::STMIB_UPD:
2193         Inst.setOpcode(ARM::SRSIB_UPD);
2194         break;
2195       default:
2196         return MCDisassembler::Fail;
2197     }
2198 
2199     // For stores (which become SRS's, the only operand is the mode.
2200     if (fieldFromInstruction(Insn, 20, 1) == 0) {
2201       // Check SRS encoding constraints
2202       if (!(fieldFromInstruction(Insn, 22, 1) == 1 &&
2203             fieldFromInstruction(Insn, 20, 1) == 0))
2204         return MCDisassembler::Fail;
2205 
2206       Inst.addOperand(
2207           MCOperand::createImm(fieldFromInstruction(Insn, 0, 4)));
2208       return S;
2209     }
2210 
2211     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
2212   }
2213 
2214   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2215     return MCDisassembler::Fail;
2216   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2217     return MCDisassembler::Fail; // Tied
2218   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2219     return MCDisassembler::Fail;
2220   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
2221     return MCDisassembler::Fail;
2222 
2223   return S;
2224 }
2225 
2226 // Check for UNPREDICTABLE predicated ESB instruction
2227 static DecodeStatus DecodeHINTInstruction(MCInst &Inst, unsigned Insn,
2228                                  uint64_t Address, const void *Decoder) {
2229   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2230   unsigned imm8 = fieldFromInstruction(Insn, 0, 8);
2231   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
2232   const FeatureBitset &FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
2233 
2234   DecodeStatus S = MCDisassembler::Success;
2235 
2236   Inst.addOperand(MCOperand::createImm(imm8));
2237 
2238   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2239     return MCDisassembler::Fail;
2240 
2241   // ESB is unpredictable if pred != AL. Without the RAS extension, it is a NOP,
2242   // so all predicates should be allowed.
2243   if (imm8 == 0x10 && pred != 0xe && ((FeatureBits[ARM::FeatureRAS]) != 0))
2244     S = MCDisassembler::SoftFail;
2245 
2246   return S;
2247 }
2248 
2249 static DecodeStatus DecodeCPSInstruction(MCInst &Inst, unsigned Insn,
2250                                  uint64_t Address, const void *Decoder) {
2251   unsigned imod = fieldFromInstruction(Insn, 18, 2);
2252   unsigned M = fieldFromInstruction(Insn, 17, 1);
2253   unsigned iflags = fieldFromInstruction(Insn, 6, 3);
2254   unsigned mode = fieldFromInstruction(Insn, 0, 5);
2255 
2256   DecodeStatus S = MCDisassembler::Success;
2257 
2258   // This decoder is called from multiple location that do not check
2259   // the full encoding is valid before they do.
2260   if (fieldFromInstruction(Insn, 5, 1) != 0 ||
2261       fieldFromInstruction(Insn, 16, 1) != 0 ||
2262       fieldFromInstruction(Insn, 20, 8) != 0x10)
2263     return MCDisassembler::Fail;
2264 
2265   // imod == '01' --> UNPREDICTABLE
2266   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
2267   // return failure here.  The '01' imod value is unprintable, so there's
2268   // nothing useful we could do even if we returned UNPREDICTABLE.
2269 
2270   if (imod == 1) return MCDisassembler::Fail;
2271 
2272   if (imod && M) {
2273     Inst.setOpcode(ARM::CPS3p);
2274     Inst.addOperand(MCOperand::createImm(imod));
2275     Inst.addOperand(MCOperand::createImm(iflags));
2276     Inst.addOperand(MCOperand::createImm(mode));
2277   } else if (imod && !M) {
2278     Inst.setOpcode(ARM::CPS2p);
2279     Inst.addOperand(MCOperand::createImm(imod));
2280     Inst.addOperand(MCOperand::createImm(iflags));
2281     if (mode) S = MCDisassembler::SoftFail;
2282   } else if (!imod && M) {
2283     Inst.setOpcode(ARM::CPS1p);
2284     Inst.addOperand(MCOperand::createImm(mode));
2285     if (iflags) S = MCDisassembler::SoftFail;
2286   } else {
2287     // imod == '00' && M == '0' --> UNPREDICTABLE
2288     Inst.setOpcode(ARM::CPS1p);
2289     Inst.addOperand(MCOperand::createImm(mode));
2290     S = MCDisassembler::SoftFail;
2291   }
2292 
2293   return S;
2294 }
2295 
2296 static DecodeStatus DecodeT2CPSInstruction(MCInst &Inst, unsigned Insn,
2297                                  uint64_t Address, const void *Decoder) {
2298   unsigned imod = fieldFromInstruction(Insn, 9, 2);
2299   unsigned M = fieldFromInstruction(Insn, 8, 1);
2300   unsigned iflags = fieldFromInstruction(Insn, 5, 3);
2301   unsigned mode = fieldFromInstruction(Insn, 0, 5);
2302 
2303   DecodeStatus S = MCDisassembler::Success;
2304 
2305   // imod == '01' --> UNPREDICTABLE
2306   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
2307   // return failure here.  The '01' imod value is unprintable, so there's
2308   // nothing useful we could do even if we returned UNPREDICTABLE.
2309 
2310   if (imod == 1) return MCDisassembler::Fail;
2311 
2312   if (imod && M) {
2313     Inst.setOpcode(ARM::t2CPS3p);
2314     Inst.addOperand(MCOperand::createImm(imod));
2315     Inst.addOperand(MCOperand::createImm(iflags));
2316     Inst.addOperand(MCOperand::createImm(mode));
2317   } else if (imod && !M) {
2318     Inst.setOpcode(ARM::t2CPS2p);
2319     Inst.addOperand(MCOperand::createImm(imod));
2320     Inst.addOperand(MCOperand::createImm(iflags));
2321     if (mode) S = MCDisassembler::SoftFail;
2322   } else if (!imod && M) {
2323     Inst.setOpcode(ARM::t2CPS1p);
2324     Inst.addOperand(MCOperand::createImm(mode));
2325     if (iflags) S = MCDisassembler::SoftFail;
2326   } else {
2327     // imod == '00' && M == '0' --> this is a HINT instruction
2328     int imm = fieldFromInstruction(Insn, 0, 8);
2329     // HINT are defined only for immediate in [0..4]
2330     if(imm > 4) return MCDisassembler::Fail;
2331     Inst.setOpcode(ARM::t2HINT);
2332     Inst.addOperand(MCOperand::createImm(imm));
2333   }
2334 
2335   return S;
2336 }
2337 
2338 static DecodeStatus DecodeT2MOVTWInstruction(MCInst &Inst, unsigned Insn,
2339                                  uint64_t Address, const void *Decoder) {
2340   DecodeStatus S = MCDisassembler::Success;
2341 
2342   unsigned Rd = fieldFromInstruction(Insn, 8, 4);
2343   unsigned imm = 0;
2344 
2345   imm |= (fieldFromInstruction(Insn, 0, 8) << 0);
2346   imm |= (fieldFromInstruction(Insn, 12, 3) << 8);
2347   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
2348   imm |= (fieldFromInstruction(Insn, 26, 1) << 11);
2349 
2350   if (Inst.getOpcode() == ARM::t2MOVTi16)
2351     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2352       return MCDisassembler::Fail;
2353   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2354     return MCDisassembler::Fail;
2355 
2356   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
2357     Inst.addOperand(MCOperand::createImm(imm));
2358 
2359   return S;
2360 }
2361 
2362 static DecodeStatus DecodeArmMOVTWInstruction(MCInst &Inst, unsigned Insn,
2363                                  uint64_t Address, const void *Decoder) {
2364   DecodeStatus S = MCDisassembler::Success;
2365 
2366   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2367   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2368   unsigned imm = 0;
2369 
2370   imm |= (fieldFromInstruction(Insn, 0, 12) << 0);
2371   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
2372 
2373   if (Inst.getOpcode() == ARM::MOVTi16)
2374     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2375       return MCDisassembler::Fail;
2376 
2377   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2378     return MCDisassembler::Fail;
2379 
2380   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
2381     Inst.addOperand(MCOperand::createImm(imm));
2382 
2383   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2384     return MCDisassembler::Fail;
2385 
2386   return S;
2387 }
2388 
2389 static DecodeStatus DecodeSMLAInstruction(MCInst &Inst, unsigned Insn,
2390                                  uint64_t Address, const void *Decoder) {
2391   DecodeStatus S = MCDisassembler::Success;
2392 
2393   unsigned Rd = fieldFromInstruction(Insn, 16, 4);
2394   unsigned Rn = fieldFromInstruction(Insn, 0, 4);
2395   unsigned Rm = fieldFromInstruction(Insn, 8, 4);
2396   unsigned Ra = fieldFromInstruction(Insn, 12, 4);
2397   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2398 
2399   if (pred == 0xF)
2400     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
2401 
2402   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2403     return MCDisassembler::Fail;
2404   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2405     return MCDisassembler::Fail;
2406   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
2407     return MCDisassembler::Fail;
2408   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
2409     return MCDisassembler::Fail;
2410 
2411   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2412     return MCDisassembler::Fail;
2413 
2414   return S;
2415 }
2416 
2417 static DecodeStatus DecodeTSTInstruction(MCInst &Inst, unsigned Insn,
2418                                   uint64_t Address, const void *Decoder) {
2419   DecodeStatus S = MCDisassembler::Success;
2420 
2421   unsigned Pred = fieldFromInstruction(Insn, 28, 4);
2422   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2423   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2424 
2425   if (Pred == 0xF)
2426     return DecodeSETPANInstruction(Inst, Insn, Address, Decoder);
2427 
2428   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2429     return MCDisassembler::Fail;
2430   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2431     return MCDisassembler::Fail;
2432   if (!Check(S, DecodePredicateOperand(Inst, Pred, Address, Decoder)))
2433     return MCDisassembler::Fail;
2434 
2435   return S;
2436 }
2437 
2438 static DecodeStatus DecodeSETPANInstruction(MCInst &Inst, unsigned Insn,
2439                                   uint64_t Address, const void *Decoder) {
2440   DecodeStatus S = MCDisassembler::Success;
2441 
2442   unsigned Imm = fieldFromInstruction(Insn, 9, 1);
2443 
2444   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
2445   const FeatureBitset &FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
2446 
2447   if (!FeatureBits[ARM::HasV8_1aOps] ||
2448       !FeatureBits[ARM::HasV8Ops])
2449     return MCDisassembler::Fail;
2450 
2451   // Decoder can be called from DecodeTST, which does not check the full
2452   // encoding is valid.
2453   if (fieldFromInstruction(Insn, 20,12) != 0xf11 ||
2454       fieldFromInstruction(Insn, 4,4) != 0)
2455     return MCDisassembler::Fail;
2456   if (fieldFromInstruction(Insn, 10,10) != 0 ||
2457       fieldFromInstruction(Insn, 0,4) != 0)
2458     S = MCDisassembler::SoftFail;
2459 
2460   Inst.setOpcode(ARM::SETPAN);
2461   Inst.addOperand(MCOperand::createImm(Imm));
2462 
2463   return S;
2464 }
2465 
2466 static DecodeStatus DecodeAddrModeImm12Operand(MCInst &Inst, unsigned Val,
2467                            uint64_t Address, const void *Decoder) {
2468   DecodeStatus S = MCDisassembler::Success;
2469 
2470   unsigned add = fieldFromInstruction(Val, 12, 1);
2471   unsigned imm = fieldFromInstruction(Val, 0, 12);
2472   unsigned Rn = fieldFromInstruction(Val, 13, 4);
2473 
2474   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2475     return MCDisassembler::Fail;
2476 
2477   if (!add) imm *= -1;
2478   if (imm == 0 && !add) imm = INT32_MIN;
2479   Inst.addOperand(MCOperand::createImm(imm));
2480   if (Rn == 15)
2481     tryAddingPcLoadReferenceComment(Address, Address + imm + 8, Decoder);
2482 
2483   return S;
2484 }
2485 
2486 static DecodeStatus DecodeAddrMode5Operand(MCInst &Inst, unsigned Val,
2487                                    uint64_t Address, const void *Decoder) {
2488   DecodeStatus S = MCDisassembler::Success;
2489 
2490   unsigned Rn = fieldFromInstruction(Val, 9, 4);
2491   // U == 1 to add imm, 0 to subtract it.
2492   unsigned U = fieldFromInstruction(Val, 8, 1);
2493   unsigned imm = fieldFromInstruction(Val, 0, 8);
2494 
2495   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2496     return MCDisassembler::Fail;
2497 
2498   if (U)
2499     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
2500   else
2501     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
2502 
2503   return S;
2504 }
2505 
2506 static DecodeStatus DecodeAddrMode5FP16Operand(MCInst &Inst, unsigned Val,
2507                                    uint64_t Address, const void *Decoder) {
2508   DecodeStatus S = MCDisassembler::Success;
2509 
2510   unsigned Rn = fieldFromInstruction(Val, 9, 4);
2511   // U == 1 to add imm, 0 to subtract it.
2512   unsigned U = fieldFromInstruction(Val, 8, 1);
2513   unsigned imm = fieldFromInstruction(Val, 0, 8);
2514 
2515   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2516     return MCDisassembler::Fail;
2517 
2518   if (U)
2519     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5FP16Opc(ARM_AM::add, imm)));
2520   else
2521     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5FP16Opc(ARM_AM::sub, imm)));
2522 
2523   return S;
2524 }
2525 
2526 static DecodeStatus DecodeAddrMode7Operand(MCInst &Inst, unsigned Val,
2527                                    uint64_t Address, const void *Decoder) {
2528   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
2529 }
2530 
2531 static DecodeStatus
2532 DecodeT2BInstruction(MCInst &Inst, unsigned Insn,
2533                      uint64_t Address, const void *Decoder) {
2534   DecodeStatus Status = MCDisassembler::Success;
2535 
2536   // Note the J1 and J2 values are from the encoded instruction.  So here
2537   // change them to I1 and I2 values via as documented:
2538   // I1 = NOT(J1 EOR S);
2539   // I2 = NOT(J2 EOR S);
2540   // and build the imm32 with one trailing zero as documented:
2541   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
2542   unsigned S = fieldFromInstruction(Insn, 26, 1);
2543   unsigned J1 = fieldFromInstruction(Insn, 13, 1);
2544   unsigned J2 = fieldFromInstruction(Insn, 11, 1);
2545   unsigned I1 = !(J1 ^ S);
2546   unsigned I2 = !(J2 ^ S);
2547   unsigned imm10 = fieldFromInstruction(Insn, 16, 10);
2548   unsigned imm11 = fieldFromInstruction(Insn, 0, 11);
2549   unsigned tmp = (S << 23) | (I1 << 22) | (I2 << 21) | (imm10 << 11) | imm11;
2550   int imm32 = SignExtend32<25>(tmp << 1);
2551   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
2552                                 true, 4, Inst, Decoder))
2553     Inst.addOperand(MCOperand::createImm(imm32));
2554 
2555   return Status;
2556 }
2557 
2558 static DecodeStatus
2559 DecodeBranchImmInstruction(MCInst &Inst, unsigned Insn,
2560                            uint64_t Address, const void *Decoder) {
2561   DecodeStatus S = MCDisassembler::Success;
2562 
2563   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2564   unsigned imm = fieldFromInstruction(Insn, 0, 24) << 2;
2565 
2566   if (pred == 0xF) {
2567     Inst.setOpcode(ARM::BLXi);
2568     imm |= fieldFromInstruction(Insn, 24, 1) << 1;
2569     if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
2570                                   true, 4, Inst, Decoder))
2571     Inst.addOperand(MCOperand::createImm(SignExtend32<26>(imm)));
2572     return S;
2573   }
2574 
2575   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
2576                                 true, 4, Inst, Decoder))
2577     Inst.addOperand(MCOperand::createImm(SignExtend32<26>(imm)));
2578   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2579     return MCDisassembler::Fail;
2580 
2581   return S;
2582 }
2583 
2584 static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
2585                                    uint64_t Address, const void *Decoder) {
2586   DecodeStatus S = MCDisassembler::Success;
2587 
2588   unsigned Rm = fieldFromInstruction(Val, 0, 4);
2589   unsigned align = fieldFromInstruction(Val, 4, 2);
2590 
2591   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2592     return MCDisassembler::Fail;
2593   if (!align)
2594     Inst.addOperand(MCOperand::createImm(0));
2595   else
2596     Inst.addOperand(MCOperand::createImm(4 << align));
2597 
2598   return S;
2599 }
2600 
2601 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Insn,
2602                                    uint64_t Address, const void *Decoder) {
2603   DecodeStatus S = MCDisassembler::Success;
2604 
2605   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2606   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2607   unsigned wb = fieldFromInstruction(Insn, 16, 4);
2608   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2609   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
2610   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2611 
2612   // First output register
2613   switch (Inst.getOpcode()) {
2614   case ARM::VLD1q16: case ARM::VLD1q32: case ARM::VLD1q64: case ARM::VLD1q8:
2615   case ARM::VLD1q16wb_fixed: case ARM::VLD1q16wb_register:
2616   case ARM::VLD1q32wb_fixed: case ARM::VLD1q32wb_register:
2617   case ARM::VLD1q64wb_fixed: case ARM::VLD1q64wb_register:
2618   case ARM::VLD1q8wb_fixed: case ARM::VLD1q8wb_register:
2619   case ARM::VLD2d16: case ARM::VLD2d32: case ARM::VLD2d8:
2620   case ARM::VLD2d16wb_fixed: case ARM::VLD2d16wb_register:
2621   case ARM::VLD2d32wb_fixed: case ARM::VLD2d32wb_register:
2622   case ARM::VLD2d8wb_fixed: case ARM::VLD2d8wb_register:
2623     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2624       return MCDisassembler::Fail;
2625     break;
2626   case ARM::VLD2b16:
2627   case ARM::VLD2b32:
2628   case ARM::VLD2b8:
2629   case ARM::VLD2b16wb_fixed:
2630   case ARM::VLD2b16wb_register:
2631   case ARM::VLD2b32wb_fixed:
2632   case ARM::VLD2b32wb_register:
2633   case ARM::VLD2b8wb_fixed:
2634   case ARM::VLD2b8wb_register:
2635     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
2636       return MCDisassembler::Fail;
2637     break;
2638   default:
2639     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2640       return MCDisassembler::Fail;
2641   }
2642 
2643   // Second output register
2644   switch (Inst.getOpcode()) {
2645     case ARM::VLD3d8:
2646     case ARM::VLD3d16:
2647     case ARM::VLD3d32:
2648     case ARM::VLD3d8_UPD:
2649     case ARM::VLD3d16_UPD:
2650     case ARM::VLD3d32_UPD:
2651     case ARM::VLD4d8:
2652     case ARM::VLD4d16:
2653     case ARM::VLD4d32:
2654     case ARM::VLD4d8_UPD:
2655     case ARM::VLD4d16_UPD:
2656     case ARM::VLD4d32_UPD:
2657       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2658         return MCDisassembler::Fail;
2659       break;
2660     case ARM::VLD3q8:
2661     case ARM::VLD3q16:
2662     case ARM::VLD3q32:
2663     case ARM::VLD3q8_UPD:
2664     case ARM::VLD3q16_UPD:
2665     case ARM::VLD3q32_UPD:
2666     case ARM::VLD4q8:
2667     case ARM::VLD4q16:
2668     case ARM::VLD4q32:
2669     case ARM::VLD4q8_UPD:
2670     case ARM::VLD4q16_UPD:
2671     case ARM::VLD4q32_UPD:
2672       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2673         return MCDisassembler::Fail;
2674       break;
2675     default:
2676       break;
2677   }
2678 
2679   // Third output register
2680   switch(Inst.getOpcode()) {
2681     case ARM::VLD3d8:
2682     case ARM::VLD3d16:
2683     case ARM::VLD3d32:
2684     case ARM::VLD3d8_UPD:
2685     case ARM::VLD3d16_UPD:
2686     case ARM::VLD3d32_UPD:
2687     case ARM::VLD4d8:
2688     case ARM::VLD4d16:
2689     case ARM::VLD4d32:
2690     case ARM::VLD4d8_UPD:
2691     case ARM::VLD4d16_UPD:
2692     case ARM::VLD4d32_UPD:
2693       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2694         return MCDisassembler::Fail;
2695       break;
2696     case ARM::VLD3q8:
2697     case ARM::VLD3q16:
2698     case ARM::VLD3q32:
2699     case ARM::VLD3q8_UPD:
2700     case ARM::VLD3q16_UPD:
2701     case ARM::VLD3q32_UPD:
2702     case ARM::VLD4q8:
2703     case ARM::VLD4q16:
2704     case ARM::VLD4q32:
2705     case ARM::VLD4q8_UPD:
2706     case ARM::VLD4q16_UPD:
2707     case ARM::VLD4q32_UPD:
2708       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2709         return MCDisassembler::Fail;
2710       break;
2711     default:
2712       break;
2713   }
2714 
2715   // Fourth output register
2716   switch (Inst.getOpcode()) {
2717     case ARM::VLD4d8:
2718     case ARM::VLD4d16:
2719     case ARM::VLD4d32:
2720     case ARM::VLD4d8_UPD:
2721     case ARM::VLD4d16_UPD:
2722     case ARM::VLD4d32_UPD:
2723       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2724         return MCDisassembler::Fail;
2725       break;
2726     case ARM::VLD4q8:
2727     case ARM::VLD4q16:
2728     case ARM::VLD4q32:
2729     case ARM::VLD4q8_UPD:
2730     case ARM::VLD4q16_UPD:
2731     case ARM::VLD4q32_UPD:
2732       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2733         return MCDisassembler::Fail;
2734       break;
2735     default:
2736       break;
2737   }
2738 
2739   // Writeback operand
2740   switch (Inst.getOpcode()) {
2741     case ARM::VLD1d8wb_fixed:
2742     case ARM::VLD1d16wb_fixed:
2743     case ARM::VLD1d32wb_fixed:
2744     case ARM::VLD1d64wb_fixed:
2745     case ARM::VLD1d8wb_register:
2746     case ARM::VLD1d16wb_register:
2747     case ARM::VLD1d32wb_register:
2748     case ARM::VLD1d64wb_register:
2749     case ARM::VLD1q8wb_fixed:
2750     case ARM::VLD1q16wb_fixed:
2751     case ARM::VLD1q32wb_fixed:
2752     case ARM::VLD1q64wb_fixed:
2753     case ARM::VLD1q8wb_register:
2754     case ARM::VLD1q16wb_register:
2755     case ARM::VLD1q32wb_register:
2756     case ARM::VLD1q64wb_register:
2757     case ARM::VLD1d8Twb_fixed:
2758     case ARM::VLD1d8Twb_register:
2759     case ARM::VLD1d16Twb_fixed:
2760     case ARM::VLD1d16Twb_register:
2761     case ARM::VLD1d32Twb_fixed:
2762     case ARM::VLD1d32Twb_register:
2763     case ARM::VLD1d64Twb_fixed:
2764     case ARM::VLD1d64Twb_register:
2765     case ARM::VLD1d8Qwb_fixed:
2766     case ARM::VLD1d8Qwb_register:
2767     case ARM::VLD1d16Qwb_fixed:
2768     case ARM::VLD1d16Qwb_register:
2769     case ARM::VLD1d32Qwb_fixed:
2770     case ARM::VLD1d32Qwb_register:
2771     case ARM::VLD1d64Qwb_fixed:
2772     case ARM::VLD1d64Qwb_register:
2773     case ARM::VLD2d8wb_fixed:
2774     case ARM::VLD2d16wb_fixed:
2775     case ARM::VLD2d32wb_fixed:
2776     case ARM::VLD2q8wb_fixed:
2777     case ARM::VLD2q16wb_fixed:
2778     case ARM::VLD2q32wb_fixed:
2779     case ARM::VLD2d8wb_register:
2780     case ARM::VLD2d16wb_register:
2781     case ARM::VLD2d32wb_register:
2782     case ARM::VLD2q8wb_register:
2783     case ARM::VLD2q16wb_register:
2784     case ARM::VLD2q32wb_register:
2785     case ARM::VLD2b8wb_fixed:
2786     case ARM::VLD2b16wb_fixed:
2787     case ARM::VLD2b32wb_fixed:
2788     case ARM::VLD2b8wb_register:
2789     case ARM::VLD2b16wb_register:
2790     case ARM::VLD2b32wb_register:
2791       Inst.addOperand(MCOperand::createImm(0));
2792       break;
2793     case ARM::VLD3d8_UPD:
2794     case ARM::VLD3d16_UPD:
2795     case ARM::VLD3d32_UPD:
2796     case ARM::VLD3q8_UPD:
2797     case ARM::VLD3q16_UPD:
2798     case ARM::VLD3q32_UPD:
2799     case ARM::VLD4d8_UPD:
2800     case ARM::VLD4d16_UPD:
2801     case ARM::VLD4d32_UPD:
2802     case ARM::VLD4q8_UPD:
2803     case ARM::VLD4q16_UPD:
2804     case ARM::VLD4q32_UPD:
2805       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2806         return MCDisassembler::Fail;
2807       break;
2808     default:
2809       break;
2810   }
2811 
2812   // AddrMode6 Base (register+alignment)
2813   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2814     return MCDisassembler::Fail;
2815 
2816   // AddrMode6 Offset (register)
2817   switch (Inst.getOpcode()) {
2818   default:
2819     // The below have been updated to have explicit am6offset split
2820     // between fixed and register offset. For those instructions not
2821     // yet updated, we need to add an additional reg0 operand for the
2822     // fixed variant.
2823     //
2824     // The fixed offset encodes as Rm == 0xd, so we check for that.
2825     if (Rm == 0xd) {
2826       Inst.addOperand(MCOperand::createReg(0));
2827       break;
2828     }
2829     // Fall through to handle the register offset variant.
2830     LLVM_FALLTHROUGH;
2831   case ARM::VLD1d8wb_fixed:
2832   case ARM::VLD1d16wb_fixed:
2833   case ARM::VLD1d32wb_fixed:
2834   case ARM::VLD1d64wb_fixed:
2835   case ARM::VLD1d8Twb_fixed:
2836   case ARM::VLD1d16Twb_fixed:
2837   case ARM::VLD1d32Twb_fixed:
2838   case ARM::VLD1d64Twb_fixed:
2839   case ARM::VLD1d8Qwb_fixed:
2840   case ARM::VLD1d16Qwb_fixed:
2841   case ARM::VLD1d32Qwb_fixed:
2842   case ARM::VLD1d64Qwb_fixed:
2843   case ARM::VLD1d8wb_register:
2844   case ARM::VLD1d16wb_register:
2845   case ARM::VLD1d32wb_register:
2846   case ARM::VLD1d64wb_register:
2847   case ARM::VLD1q8wb_fixed:
2848   case ARM::VLD1q16wb_fixed:
2849   case ARM::VLD1q32wb_fixed:
2850   case ARM::VLD1q64wb_fixed:
2851   case ARM::VLD1q8wb_register:
2852   case ARM::VLD1q16wb_register:
2853   case ARM::VLD1q32wb_register:
2854   case ARM::VLD1q64wb_register:
2855     // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2856     // variant encodes Rm == 0xf. Anything else is a register offset post-
2857     // increment and we need to add the register operand to the instruction.
2858     if (Rm != 0xD && Rm != 0xF &&
2859         !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2860       return MCDisassembler::Fail;
2861     break;
2862   case ARM::VLD2d8wb_fixed:
2863   case ARM::VLD2d16wb_fixed:
2864   case ARM::VLD2d32wb_fixed:
2865   case ARM::VLD2b8wb_fixed:
2866   case ARM::VLD2b16wb_fixed:
2867   case ARM::VLD2b32wb_fixed:
2868   case ARM::VLD2q8wb_fixed:
2869   case ARM::VLD2q16wb_fixed:
2870   case ARM::VLD2q32wb_fixed:
2871     break;
2872   }
2873 
2874   return S;
2875 }
2876 
2877 static DecodeStatus DecodeVLDST1Instruction(MCInst &Inst, unsigned Insn,
2878                                    uint64_t Address, const void *Decoder) {
2879   unsigned type = fieldFromInstruction(Insn, 8, 4);
2880   unsigned align = fieldFromInstruction(Insn, 4, 2);
2881   if (type == 6 && (align & 2)) return MCDisassembler::Fail;
2882   if (type == 7 && (align & 2)) return MCDisassembler::Fail;
2883   if (type == 10 && align == 3) return MCDisassembler::Fail;
2884 
2885   unsigned load = fieldFromInstruction(Insn, 21, 1);
2886   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2887               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2888 }
2889 
2890 static DecodeStatus DecodeVLDST2Instruction(MCInst &Inst, unsigned Insn,
2891                                    uint64_t Address, const void *Decoder) {
2892   unsigned size = fieldFromInstruction(Insn, 6, 2);
2893   if (size == 3) return MCDisassembler::Fail;
2894 
2895   unsigned type = fieldFromInstruction(Insn, 8, 4);
2896   unsigned align = fieldFromInstruction(Insn, 4, 2);
2897   if (type == 8 && align == 3) return MCDisassembler::Fail;
2898   if (type == 9 && align == 3) return MCDisassembler::Fail;
2899 
2900   unsigned load = fieldFromInstruction(Insn, 21, 1);
2901   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2902               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2903 }
2904 
2905 static DecodeStatus DecodeVLDST3Instruction(MCInst &Inst, unsigned Insn,
2906                                    uint64_t Address, const void *Decoder) {
2907   unsigned size = fieldFromInstruction(Insn, 6, 2);
2908   if (size == 3) return MCDisassembler::Fail;
2909 
2910   unsigned align = fieldFromInstruction(Insn, 4, 2);
2911   if (align & 2) return MCDisassembler::Fail;
2912 
2913   unsigned load = fieldFromInstruction(Insn, 21, 1);
2914   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2915               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2916 }
2917 
2918 static DecodeStatus DecodeVLDST4Instruction(MCInst &Inst, unsigned Insn,
2919                                    uint64_t Address, const void *Decoder) {
2920   unsigned size = fieldFromInstruction(Insn, 6, 2);
2921   if (size == 3) return MCDisassembler::Fail;
2922 
2923   unsigned load = fieldFromInstruction(Insn, 21, 1);
2924   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2925               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2926 }
2927 
2928 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Insn,
2929                                  uint64_t Address, const void *Decoder) {
2930   DecodeStatus S = MCDisassembler::Success;
2931 
2932   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2933   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2934   unsigned wb = fieldFromInstruction(Insn, 16, 4);
2935   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2936   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
2937   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2938 
2939   // Writeback Operand
2940   switch (Inst.getOpcode()) {
2941     case ARM::VST1d8wb_fixed:
2942     case ARM::VST1d16wb_fixed:
2943     case ARM::VST1d32wb_fixed:
2944     case ARM::VST1d64wb_fixed:
2945     case ARM::VST1d8wb_register:
2946     case ARM::VST1d16wb_register:
2947     case ARM::VST1d32wb_register:
2948     case ARM::VST1d64wb_register:
2949     case ARM::VST1q8wb_fixed:
2950     case ARM::VST1q16wb_fixed:
2951     case ARM::VST1q32wb_fixed:
2952     case ARM::VST1q64wb_fixed:
2953     case ARM::VST1q8wb_register:
2954     case ARM::VST1q16wb_register:
2955     case ARM::VST1q32wb_register:
2956     case ARM::VST1q64wb_register:
2957     case ARM::VST1d8Twb_fixed:
2958     case ARM::VST1d16Twb_fixed:
2959     case ARM::VST1d32Twb_fixed:
2960     case ARM::VST1d64Twb_fixed:
2961     case ARM::VST1d8Twb_register:
2962     case ARM::VST1d16Twb_register:
2963     case ARM::VST1d32Twb_register:
2964     case ARM::VST1d64Twb_register:
2965     case ARM::VST1d8Qwb_fixed:
2966     case ARM::VST1d16Qwb_fixed:
2967     case ARM::VST1d32Qwb_fixed:
2968     case ARM::VST1d64Qwb_fixed:
2969     case ARM::VST1d8Qwb_register:
2970     case ARM::VST1d16Qwb_register:
2971     case ARM::VST1d32Qwb_register:
2972     case ARM::VST1d64Qwb_register:
2973     case ARM::VST2d8wb_fixed:
2974     case ARM::VST2d16wb_fixed:
2975     case ARM::VST2d32wb_fixed:
2976     case ARM::VST2d8wb_register:
2977     case ARM::VST2d16wb_register:
2978     case ARM::VST2d32wb_register:
2979     case ARM::VST2q8wb_fixed:
2980     case ARM::VST2q16wb_fixed:
2981     case ARM::VST2q32wb_fixed:
2982     case ARM::VST2q8wb_register:
2983     case ARM::VST2q16wb_register:
2984     case ARM::VST2q32wb_register:
2985     case ARM::VST2b8wb_fixed:
2986     case ARM::VST2b16wb_fixed:
2987     case ARM::VST2b32wb_fixed:
2988     case ARM::VST2b8wb_register:
2989     case ARM::VST2b16wb_register:
2990     case ARM::VST2b32wb_register:
2991       if (Rm == 0xF)
2992         return MCDisassembler::Fail;
2993       Inst.addOperand(MCOperand::createImm(0));
2994       break;
2995     case ARM::VST3d8_UPD:
2996     case ARM::VST3d16_UPD:
2997     case ARM::VST3d32_UPD:
2998     case ARM::VST3q8_UPD:
2999     case ARM::VST3q16_UPD:
3000     case ARM::VST3q32_UPD:
3001     case ARM::VST4d8_UPD:
3002     case ARM::VST4d16_UPD:
3003     case ARM::VST4d32_UPD:
3004     case ARM::VST4q8_UPD:
3005     case ARM::VST4q16_UPD:
3006     case ARM::VST4q32_UPD:
3007       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
3008         return MCDisassembler::Fail;
3009       break;
3010     default:
3011       break;
3012   }
3013 
3014   // AddrMode6 Base (register+alignment)
3015   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
3016     return MCDisassembler::Fail;
3017 
3018   // AddrMode6 Offset (register)
3019   switch (Inst.getOpcode()) {
3020     default:
3021       if (Rm == 0xD)
3022         Inst.addOperand(MCOperand::createReg(0));
3023       else if (Rm != 0xF) {
3024         if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3025           return MCDisassembler::Fail;
3026       }
3027       break;
3028     case ARM::VST1d8wb_fixed:
3029     case ARM::VST1d16wb_fixed:
3030     case ARM::VST1d32wb_fixed:
3031     case ARM::VST1d64wb_fixed:
3032     case ARM::VST1q8wb_fixed:
3033     case ARM::VST1q16wb_fixed:
3034     case ARM::VST1q32wb_fixed:
3035     case ARM::VST1q64wb_fixed:
3036     case ARM::VST1d8Twb_fixed:
3037     case ARM::VST1d16Twb_fixed:
3038     case ARM::VST1d32Twb_fixed:
3039     case ARM::VST1d64Twb_fixed:
3040     case ARM::VST1d8Qwb_fixed:
3041     case ARM::VST1d16Qwb_fixed:
3042     case ARM::VST1d32Qwb_fixed:
3043     case ARM::VST1d64Qwb_fixed:
3044     case ARM::VST2d8wb_fixed:
3045     case ARM::VST2d16wb_fixed:
3046     case ARM::VST2d32wb_fixed:
3047     case ARM::VST2q8wb_fixed:
3048     case ARM::VST2q16wb_fixed:
3049     case ARM::VST2q32wb_fixed:
3050     case ARM::VST2b8wb_fixed:
3051     case ARM::VST2b16wb_fixed:
3052     case ARM::VST2b32wb_fixed:
3053       break;
3054   }
3055 
3056   // First input register
3057   switch (Inst.getOpcode()) {
3058   case ARM::VST1q16:
3059   case ARM::VST1q32:
3060   case ARM::VST1q64:
3061   case ARM::VST1q8:
3062   case ARM::VST1q16wb_fixed:
3063   case ARM::VST1q16wb_register:
3064   case ARM::VST1q32wb_fixed:
3065   case ARM::VST1q32wb_register:
3066   case ARM::VST1q64wb_fixed:
3067   case ARM::VST1q64wb_register:
3068   case ARM::VST1q8wb_fixed:
3069   case ARM::VST1q8wb_register:
3070   case ARM::VST2d16:
3071   case ARM::VST2d32:
3072   case ARM::VST2d8:
3073   case ARM::VST2d16wb_fixed:
3074   case ARM::VST2d16wb_register:
3075   case ARM::VST2d32wb_fixed:
3076   case ARM::VST2d32wb_register:
3077   case ARM::VST2d8wb_fixed:
3078   case ARM::VST2d8wb_register:
3079     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
3080       return MCDisassembler::Fail;
3081     break;
3082   case ARM::VST2b16:
3083   case ARM::VST2b32:
3084   case ARM::VST2b8:
3085   case ARM::VST2b16wb_fixed:
3086   case ARM::VST2b16wb_register:
3087   case ARM::VST2b32wb_fixed:
3088   case ARM::VST2b32wb_register:
3089   case ARM::VST2b8wb_fixed:
3090   case ARM::VST2b8wb_register:
3091     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
3092       return MCDisassembler::Fail;
3093     break;
3094   default:
3095     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3096       return MCDisassembler::Fail;
3097   }
3098 
3099   // Second input register
3100   switch (Inst.getOpcode()) {
3101     case ARM::VST3d8:
3102     case ARM::VST3d16:
3103     case ARM::VST3d32:
3104     case ARM::VST3d8_UPD:
3105     case ARM::VST3d16_UPD:
3106     case ARM::VST3d32_UPD:
3107     case ARM::VST4d8:
3108     case ARM::VST4d16:
3109     case ARM::VST4d32:
3110     case ARM::VST4d8_UPD:
3111     case ARM::VST4d16_UPD:
3112     case ARM::VST4d32_UPD:
3113       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
3114         return MCDisassembler::Fail;
3115       break;
3116     case ARM::VST3q8:
3117     case ARM::VST3q16:
3118     case ARM::VST3q32:
3119     case ARM::VST3q8_UPD:
3120     case ARM::VST3q16_UPD:
3121     case ARM::VST3q32_UPD:
3122     case ARM::VST4q8:
3123     case ARM::VST4q16:
3124     case ARM::VST4q32:
3125     case ARM::VST4q8_UPD:
3126     case ARM::VST4q16_UPD:
3127     case ARM::VST4q32_UPD:
3128       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
3129         return MCDisassembler::Fail;
3130       break;
3131     default:
3132       break;
3133   }
3134 
3135   // Third input register
3136   switch (Inst.getOpcode()) {
3137     case ARM::VST3d8:
3138     case ARM::VST3d16:
3139     case ARM::VST3d32:
3140     case ARM::VST3d8_UPD:
3141     case ARM::VST3d16_UPD:
3142     case ARM::VST3d32_UPD:
3143     case ARM::VST4d8:
3144     case ARM::VST4d16:
3145     case ARM::VST4d32:
3146     case ARM::VST4d8_UPD:
3147     case ARM::VST4d16_UPD:
3148     case ARM::VST4d32_UPD:
3149       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
3150         return MCDisassembler::Fail;
3151       break;
3152     case ARM::VST3q8:
3153     case ARM::VST3q16:
3154     case ARM::VST3q32:
3155     case ARM::VST3q8_UPD:
3156     case ARM::VST3q16_UPD:
3157     case ARM::VST3q32_UPD:
3158     case ARM::VST4q8:
3159     case ARM::VST4q16:
3160     case ARM::VST4q32:
3161     case ARM::VST4q8_UPD:
3162     case ARM::VST4q16_UPD:
3163     case ARM::VST4q32_UPD:
3164       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
3165         return MCDisassembler::Fail;
3166       break;
3167     default:
3168       break;
3169   }
3170 
3171   // Fourth input register
3172   switch (Inst.getOpcode()) {
3173     case ARM::VST4d8:
3174     case ARM::VST4d16:
3175     case ARM::VST4d32:
3176     case ARM::VST4d8_UPD:
3177     case ARM::VST4d16_UPD:
3178     case ARM::VST4d32_UPD:
3179       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
3180         return MCDisassembler::Fail;
3181       break;
3182     case ARM::VST4q8:
3183     case ARM::VST4q16:
3184     case ARM::VST4q32:
3185     case ARM::VST4q8_UPD:
3186     case ARM::VST4q16_UPD:
3187     case ARM::VST4q32_UPD:
3188       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
3189         return MCDisassembler::Fail;
3190       break;
3191     default:
3192       break;
3193   }
3194 
3195   return S;
3196 }
3197 
3198 static DecodeStatus DecodeVLD1DupInstruction(MCInst &Inst, unsigned Insn,
3199                                     uint64_t Address, const void *Decoder) {
3200   DecodeStatus S = MCDisassembler::Success;
3201 
3202   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3203   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3204   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3205   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3206   unsigned align = fieldFromInstruction(Insn, 4, 1);
3207   unsigned size = fieldFromInstruction(Insn, 6, 2);
3208 
3209   if (size == 0 && align == 1)
3210     return MCDisassembler::Fail;
3211   align *= (1 << size);
3212 
3213   switch (Inst.getOpcode()) {
3214   case ARM::VLD1DUPq16: case ARM::VLD1DUPq32: case ARM::VLD1DUPq8:
3215   case ARM::VLD1DUPq16wb_fixed: case ARM::VLD1DUPq16wb_register:
3216   case ARM::VLD1DUPq32wb_fixed: case ARM::VLD1DUPq32wb_register:
3217   case ARM::VLD1DUPq8wb_fixed: case ARM::VLD1DUPq8wb_register:
3218     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
3219       return MCDisassembler::Fail;
3220     break;
3221   default:
3222     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3223       return MCDisassembler::Fail;
3224     break;
3225   }
3226   if (Rm != 0xF) {
3227     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3228       return MCDisassembler::Fail;
3229   }
3230 
3231   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3232     return MCDisassembler::Fail;
3233   Inst.addOperand(MCOperand::createImm(align));
3234 
3235   // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
3236   // variant encodes Rm == 0xf. Anything else is a register offset post-
3237   // increment and we need to add the register operand to the instruction.
3238   if (Rm != 0xD && Rm != 0xF &&
3239       !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3240     return MCDisassembler::Fail;
3241 
3242   return S;
3243 }
3244 
3245 static DecodeStatus DecodeVLD2DupInstruction(MCInst &Inst, unsigned Insn,
3246                                     uint64_t Address, const void *Decoder) {
3247   DecodeStatus S = MCDisassembler::Success;
3248 
3249   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3250   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3251   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3252   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3253   unsigned align = fieldFromInstruction(Insn, 4, 1);
3254   unsigned size = 1 << fieldFromInstruction(Insn, 6, 2);
3255   align *= 2*size;
3256 
3257   switch (Inst.getOpcode()) {
3258   case ARM::VLD2DUPd16: case ARM::VLD2DUPd32: case ARM::VLD2DUPd8:
3259   case ARM::VLD2DUPd16wb_fixed: case ARM::VLD2DUPd16wb_register:
3260   case ARM::VLD2DUPd32wb_fixed: case ARM::VLD2DUPd32wb_register:
3261   case ARM::VLD2DUPd8wb_fixed: case ARM::VLD2DUPd8wb_register:
3262     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
3263       return MCDisassembler::Fail;
3264     break;
3265   case ARM::VLD2DUPd16x2: case ARM::VLD2DUPd32x2: case ARM::VLD2DUPd8x2:
3266   case ARM::VLD2DUPd16x2wb_fixed: case ARM::VLD2DUPd16x2wb_register:
3267   case ARM::VLD2DUPd32x2wb_fixed: case ARM::VLD2DUPd32x2wb_register:
3268   case ARM::VLD2DUPd8x2wb_fixed: case ARM::VLD2DUPd8x2wb_register:
3269     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
3270       return MCDisassembler::Fail;
3271     break;
3272   default:
3273     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3274       return MCDisassembler::Fail;
3275     break;
3276   }
3277 
3278   if (Rm != 0xF)
3279     Inst.addOperand(MCOperand::createImm(0));
3280 
3281   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3282     return MCDisassembler::Fail;
3283   Inst.addOperand(MCOperand::createImm(align));
3284 
3285   if (Rm != 0xD && Rm != 0xF) {
3286     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3287       return MCDisassembler::Fail;
3288   }
3289 
3290   return S;
3291 }
3292 
3293 static DecodeStatus DecodeVLD3DupInstruction(MCInst &Inst, unsigned Insn,
3294                                     uint64_t Address, const void *Decoder) {
3295   DecodeStatus S = MCDisassembler::Success;
3296 
3297   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3298   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3299   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3300   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3301   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
3302 
3303   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3304     return MCDisassembler::Fail;
3305   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
3306     return MCDisassembler::Fail;
3307   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
3308     return MCDisassembler::Fail;
3309   if (Rm != 0xF) {
3310     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3311       return MCDisassembler::Fail;
3312   }
3313 
3314   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3315     return MCDisassembler::Fail;
3316   Inst.addOperand(MCOperand::createImm(0));
3317 
3318   if (Rm == 0xD)
3319     Inst.addOperand(MCOperand::createReg(0));
3320   else if (Rm != 0xF) {
3321     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3322       return MCDisassembler::Fail;
3323   }
3324 
3325   return S;
3326 }
3327 
3328 static DecodeStatus DecodeVLD4DupInstruction(MCInst &Inst, unsigned Insn,
3329                                     uint64_t Address, const void *Decoder) {
3330   DecodeStatus S = MCDisassembler::Success;
3331 
3332   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3333   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3334   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3335   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3336   unsigned size = fieldFromInstruction(Insn, 6, 2);
3337   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
3338   unsigned align = fieldFromInstruction(Insn, 4, 1);
3339 
3340   if (size == 0x3) {
3341     if (align == 0)
3342       return MCDisassembler::Fail;
3343     align = 16;
3344   } else {
3345     if (size == 2) {
3346       align *= 8;
3347     } else {
3348       size = 1 << size;
3349       align *= 4*size;
3350     }
3351   }
3352 
3353   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3354     return MCDisassembler::Fail;
3355   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
3356     return MCDisassembler::Fail;
3357   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
3358     return MCDisassembler::Fail;
3359   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
3360     return MCDisassembler::Fail;
3361   if (Rm != 0xF) {
3362     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3363       return MCDisassembler::Fail;
3364   }
3365 
3366   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3367     return MCDisassembler::Fail;
3368   Inst.addOperand(MCOperand::createImm(align));
3369 
3370   if (Rm == 0xD)
3371     Inst.addOperand(MCOperand::createReg(0));
3372   else if (Rm != 0xF) {
3373     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3374       return MCDisassembler::Fail;
3375   }
3376 
3377   return S;
3378 }
3379 
3380 static DecodeStatus
3381 DecodeNEONModImmInstruction(MCInst &Inst, unsigned Insn,
3382                             uint64_t Address, const void *Decoder) {
3383   DecodeStatus S = MCDisassembler::Success;
3384 
3385   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3386   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3387   unsigned imm = fieldFromInstruction(Insn, 0, 4);
3388   imm |= fieldFromInstruction(Insn, 16, 3) << 4;
3389   imm |= fieldFromInstruction(Insn, 24, 1) << 7;
3390   imm |= fieldFromInstruction(Insn, 8, 4) << 8;
3391   imm |= fieldFromInstruction(Insn, 5, 1) << 12;
3392   unsigned Q = fieldFromInstruction(Insn, 6, 1);
3393 
3394   if (Q) {
3395     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3396     return MCDisassembler::Fail;
3397   } else {
3398     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3399     return MCDisassembler::Fail;
3400   }
3401 
3402   Inst.addOperand(MCOperand::createImm(imm));
3403 
3404   switch (Inst.getOpcode()) {
3405     case ARM::VORRiv4i16:
3406     case ARM::VORRiv2i32:
3407     case ARM::VBICiv4i16:
3408     case ARM::VBICiv2i32:
3409       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3410         return MCDisassembler::Fail;
3411       break;
3412     case ARM::VORRiv8i16:
3413     case ARM::VORRiv4i32:
3414     case ARM::VBICiv8i16:
3415     case ARM::VBICiv4i32:
3416       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3417         return MCDisassembler::Fail;
3418       break;
3419     default:
3420       break;
3421   }
3422 
3423   return S;
3424 }
3425 
3426 static DecodeStatus DecodeVSHLMaxInstruction(MCInst &Inst, unsigned Insn,
3427                                         uint64_t Address, const void *Decoder) {
3428   DecodeStatus S = MCDisassembler::Success;
3429 
3430   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3431   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3432   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3433   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
3434   unsigned size = fieldFromInstruction(Insn, 18, 2);
3435 
3436   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3437     return MCDisassembler::Fail;
3438   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
3439     return MCDisassembler::Fail;
3440   Inst.addOperand(MCOperand::createImm(8 << size));
3441 
3442   return S;
3443 }
3444 
3445 static DecodeStatus DecodeShiftRight8Imm(MCInst &Inst, unsigned Val,
3446                                uint64_t Address, const void *Decoder) {
3447   Inst.addOperand(MCOperand::createImm(8 - Val));
3448   return MCDisassembler::Success;
3449 }
3450 
3451 static DecodeStatus DecodeShiftRight16Imm(MCInst &Inst, unsigned Val,
3452                                uint64_t Address, const void *Decoder) {
3453   Inst.addOperand(MCOperand::createImm(16 - Val));
3454   return MCDisassembler::Success;
3455 }
3456 
3457 static DecodeStatus DecodeShiftRight32Imm(MCInst &Inst, unsigned Val,
3458                                uint64_t Address, const void *Decoder) {
3459   Inst.addOperand(MCOperand::createImm(32 - Val));
3460   return MCDisassembler::Success;
3461 }
3462 
3463 static DecodeStatus DecodeShiftRight64Imm(MCInst &Inst, unsigned Val,
3464                                uint64_t Address, const void *Decoder) {
3465   Inst.addOperand(MCOperand::createImm(64 - Val));
3466   return MCDisassembler::Success;
3467 }
3468 
3469 static DecodeStatus DecodeTBLInstruction(MCInst &Inst, unsigned Insn,
3470                                uint64_t Address, const void *Decoder) {
3471   DecodeStatus S = MCDisassembler::Success;
3472 
3473   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3474   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3475   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3476   Rn |= fieldFromInstruction(Insn, 7, 1) << 4;
3477   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3478   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
3479   unsigned op = fieldFromInstruction(Insn, 6, 1);
3480 
3481   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3482     return MCDisassembler::Fail;
3483   if (op) {
3484     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3485     return MCDisassembler::Fail; // Writeback
3486   }
3487 
3488   switch (Inst.getOpcode()) {
3489   case ARM::VTBL2:
3490   case ARM::VTBX2:
3491     if (!Check(S, DecodeDPairRegisterClass(Inst, Rn, Address, Decoder)))
3492       return MCDisassembler::Fail;
3493     break;
3494   default:
3495     if (!Check(S, DecodeDPRRegisterClass(Inst, Rn, Address, Decoder)))
3496       return MCDisassembler::Fail;
3497   }
3498 
3499   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
3500     return MCDisassembler::Fail;
3501 
3502   return S;
3503 }
3504 
3505 static DecodeStatus DecodeThumbAddSpecialReg(MCInst &Inst, uint16_t Insn,
3506                                      uint64_t Address, const void *Decoder) {
3507   DecodeStatus S = MCDisassembler::Success;
3508 
3509   unsigned dst = fieldFromInstruction(Insn, 8, 3);
3510   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3511 
3512   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
3513     return MCDisassembler::Fail;
3514 
3515   switch(Inst.getOpcode()) {
3516     default:
3517       return MCDisassembler::Fail;
3518     case ARM::tADR:
3519       break; // tADR does not explicitly represent the PC as an operand.
3520     case ARM::tADDrSPi:
3521       Inst.addOperand(MCOperand::createReg(ARM::SP));
3522       break;
3523   }
3524 
3525   Inst.addOperand(MCOperand::createImm(imm));
3526   return S;
3527 }
3528 
3529 static DecodeStatus DecodeThumbBROperand(MCInst &Inst, unsigned Val,
3530                                  uint64_t Address, const void *Decoder) {
3531   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<12>(Val<<1) + 4,
3532                                 true, 2, Inst, Decoder))
3533     Inst.addOperand(MCOperand::createImm(SignExtend32<12>(Val << 1)));
3534   return MCDisassembler::Success;
3535 }
3536 
3537 static DecodeStatus DecodeT2BROperand(MCInst &Inst, unsigned Val,
3538                                  uint64_t Address, const void *Decoder) {
3539   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<21>(Val) + 4,
3540                                 true, 4, Inst, Decoder))
3541     Inst.addOperand(MCOperand::createImm(SignExtend32<21>(Val)));
3542   return MCDisassembler::Success;
3543 }
3544 
3545 static DecodeStatus DecodeThumbCmpBROperand(MCInst &Inst, unsigned Val,
3546                                  uint64_t Address, const void *Decoder) {
3547   if (!tryAddingSymbolicOperand(Address, Address + (Val<<1) + 4,
3548                                 true, 2, Inst, Decoder))
3549     Inst.addOperand(MCOperand::createImm(Val << 1));
3550   return MCDisassembler::Success;
3551 }
3552 
3553 static DecodeStatus DecodeThumbAddrModeRR(MCInst &Inst, unsigned Val,
3554                                  uint64_t Address, const void *Decoder) {
3555   DecodeStatus S = MCDisassembler::Success;
3556 
3557   unsigned Rn = fieldFromInstruction(Val, 0, 3);
3558   unsigned Rm = fieldFromInstruction(Val, 3, 3);
3559 
3560   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
3561     return MCDisassembler::Fail;
3562   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
3563     return MCDisassembler::Fail;
3564 
3565   return S;
3566 }
3567 
3568 static DecodeStatus DecodeThumbAddrModeIS(MCInst &Inst, unsigned Val,
3569                                   uint64_t Address, const void *Decoder) {
3570   DecodeStatus S = MCDisassembler::Success;
3571 
3572   unsigned Rn = fieldFromInstruction(Val, 0, 3);
3573   unsigned imm = fieldFromInstruction(Val, 3, 5);
3574 
3575   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
3576     return MCDisassembler::Fail;
3577   Inst.addOperand(MCOperand::createImm(imm));
3578 
3579   return S;
3580 }
3581 
3582 static DecodeStatus DecodeThumbAddrModePC(MCInst &Inst, unsigned Val,
3583                                   uint64_t Address, const void *Decoder) {
3584   unsigned imm = Val << 2;
3585 
3586   Inst.addOperand(MCOperand::createImm(imm));
3587   tryAddingPcLoadReferenceComment(Address, (Address & ~2u) + imm + 4, Decoder);
3588 
3589   return MCDisassembler::Success;
3590 }
3591 
3592 static DecodeStatus DecodeThumbAddrModeSP(MCInst &Inst, unsigned Val,
3593                                   uint64_t Address, const void *Decoder) {
3594   Inst.addOperand(MCOperand::createReg(ARM::SP));
3595   Inst.addOperand(MCOperand::createImm(Val));
3596 
3597   return MCDisassembler::Success;
3598 }
3599 
3600 static DecodeStatus DecodeT2AddrModeSOReg(MCInst &Inst, unsigned Val,
3601                                   uint64_t Address, const void *Decoder) {
3602   DecodeStatus S = MCDisassembler::Success;
3603 
3604   unsigned Rn = fieldFromInstruction(Val, 6, 4);
3605   unsigned Rm = fieldFromInstruction(Val, 2, 4);
3606   unsigned imm = fieldFromInstruction(Val, 0, 2);
3607 
3608   // Thumb stores cannot use PC as dest register.
3609   switch (Inst.getOpcode()) {
3610   case ARM::t2STRHs:
3611   case ARM::t2STRBs:
3612   case ARM::t2STRs:
3613     if (Rn == 15)
3614       return MCDisassembler::Fail;
3615     break;
3616   default:
3617     break;
3618   }
3619 
3620   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3621     return MCDisassembler::Fail;
3622   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
3623     return MCDisassembler::Fail;
3624   Inst.addOperand(MCOperand::createImm(imm));
3625 
3626   return S;
3627 }
3628 
3629 static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Insn,
3630                               uint64_t Address, const void *Decoder) {
3631   DecodeStatus S = MCDisassembler::Success;
3632 
3633   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3634   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3635 
3636   const FeatureBitset &featureBits =
3637     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3638 
3639   bool hasMP = featureBits[ARM::FeatureMP];
3640   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3641 
3642   if (Rn == 15) {
3643     switch (Inst.getOpcode()) {
3644     case ARM::t2LDRBs:
3645       Inst.setOpcode(ARM::t2LDRBpci);
3646       break;
3647     case ARM::t2LDRHs:
3648       Inst.setOpcode(ARM::t2LDRHpci);
3649       break;
3650     case ARM::t2LDRSHs:
3651       Inst.setOpcode(ARM::t2LDRSHpci);
3652       break;
3653     case ARM::t2LDRSBs:
3654       Inst.setOpcode(ARM::t2LDRSBpci);
3655       break;
3656     case ARM::t2LDRs:
3657       Inst.setOpcode(ARM::t2LDRpci);
3658       break;
3659     case ARM::t2PLDs:
3660       Inst.setOpcode(ARM::t2PLDpci);
3661       break;
3662     case ARM::t2PLIs:
3663       Inst.setOpcode(ARM::t2PLIpci);
3664       break;
3665     default:
3666       return MCDisassembler::Fail;
3667     }
3668 
3669     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3670   }
3671 
3672   if (Rt == 15) {
3673     switch (Inst.getOpcode()) {
3674     case ARM::t2LDRSHs:
3675       return MCDisassembler::Fail;
3676     case ARM::t2LDRHs:
3677       Inst.setOpcode(ARM::t2PLDWs);
3678       break;
3679     case ARM::t2LDRSBs:
3680       Inst.setOpcode(ARM::t2PLIs);
3681       break;
3682     default:
3683       break;
3684     }
3685   }
3686 
3687   switch (Inst.getOpcode()) {
3688     case ARM::t2PLDs:
3689       break;
3690     case ARM::t2PLIs:
3691       if (!hasV7Ops)
3692         return MCDisassembler::Fail;
3693       break;
3694     case ARM::t2PLDWs:
3695       if (!hasV7Ops || !hasMP)
3696         return MCDisassembler::Fail;
3697       break;
3698     default:
3699       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3700         return MCDisassembler::Fail;
3701   }
3702 
3703   unsigned addrmode = fieldFromInstruction(Insn, 4, 2);
3704   addrmode |= fieldFromInstruction(Insn, 0, 4) << 2;
3705   addrmode |= fieldFromInstruction(Insn, 16, 4) << 6;
3706   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
3707     return MCDisassembler::Fail;
3708 
3709   return S;
3710 }
3711 
3712 static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
3713                                 uint64_t Address, const void* Decoder) {
3714   DecodeStatus S = MCDisassembler::Success;
3715 
3716   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3717   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3718   unsigned U = fieldFromInstruction(Insn, 9, 1);
3719   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3720   imm |= (U << 8);
3721   imm |= (Rn << 9);
3722   unsigned add = fieldFromInstruction(Insn, 9, 1);
3723 
3724   const FeatureBitset &featureBits =
3725     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3726 
3727   bool hasMP = featureBits[ARM::FeatureMP];
3728   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3729 
3730   if (Rn == 15) {
3731     switch (Inst.getOpcode()) {
3732     case ARM::t2LDRi8:
3733       Inst.setOpcode(ARM::t2LDRpci);
3734       break;
3735     case ARM::t2LDRBi8:
3736       Inst.setOpcode(ARM::t2LDRBpci);
3737       break;
3738     case ARM::t2LDRSBi8:
3739       Inst.setOpcode(ARM::t2LDRSBpci);
3740       break;
3741     case ARM::t2LDRHi8:
3742       Inst.setOpcode(ARM::t2LDRHpci);
3743       break;
3744     case ARM::t2LDRSHi8:
3745       Inst.setOpcode(ARM::t2LDRSHpci);
3746       break;
3747     case ARM::t2PLDi8:
3748       Inst.setOpcode(ARM::t2PLDpci);
3749       break;
3750     case ARM::t2PLIi8:
3751       Inst.setOpcode(ARM::t2PLIpci);
3752       break;
3753     default:
3754       return MCDisassembler::Fail;
3755     }
3756     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3757   }
3758 
3759   if (Rt == 15) {
3760     switch (Inst.getOpcode()) {
3761     case ARM::t2LDRSHi8:
3762       return MCDisassembler::Fail;
3763     case ARM::t2LDRHi8:
3764       if (!add)
3765         Inst.setOpcode(ARM::t2PLDWi8);
3766       break;
3767     case ARM::t2LDRSBi8:
3768       Inst.setOpcode(ARM::t2PLIi8);
3769       break;
3770     default:
3771       break;
3772     }
3773   }
3774 
3775   switch (Inst.getOpcode()) {
3776   case ARM::t2PLDi8:
3777     break;
3778   case ARM::t2PLIi8:
3779     if (!hasV7Ops)
3780       return MCDisassembler::Fail;
3781     break;
3782   case ARM::t2PLDWi8:
3783       if (!hasV7Ops || !hasMP)
3784         return MCDisassembler::Fail;
3785       break;
3786   default:
3787     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3788       return MCDisassembler::Fail;
3789   }
3790 
3791   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
3792     return MCDisassembler::Fail;
3793   return S;
3794 }
3795 
3796 static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
3797                                 uint64_t Address, const void* Decoder) {
3798   DecodeStatus S = MCDisassembler::Success;
3799 
3800   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3801   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3802   unsigned imm = fieldFromInstruction(Insn, 0, 12);
3803   imm |= (Rn << 13);
3804 
3805   const FeatureBitset &featureBits =
3806     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3807 
3808   bool hasMP = featureBits[ARM::FeatureMP];
3809   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3810 
3811   if (Rn == 15) {
3812     switch (Inst.getOpcode()) {
3813     case ARM::t2LDRi12:
3814       Inst.setOpcode(ARM::t2LDRpci);
3815       break;
3816     case ARM::t2LDRHi12:
3817       Inst.setOpcode(ARM::t2LDRHpci);
3818       break;
3819     case ARM::t2LDRSHi12:
3820       Inst.setOpcode(ARM::t2LDRSHpci);
3821       break;
3822     case ARM::t2LDRBi12:
3823       Inst.setOpcode(ARM::t2LDRBpci);
3824       break;
3825     case ARM::t2LDRSBi12:
3826       Inst.setOpcode(ARM::t2LDRSBpci);
3827       break;
3828     case ARM::t2PLDi12:
3829       Inst.setOpcode(ARM::t2PLDpci);
3830       break;
3831     case ARM::t2PLIi12:
3832       Inst.setOpcode(ARM::t2PLIpci);
3833       break;
3834     default:
3835       return MCDisassembler::Fail;
3836     }
3837     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3838   }
3839 
3840   if (Rt == 15) {
3841     switch (Inst.getOpcode()) {
3842     case ARM::t2LDRSHi12:
3843       return MCDisassembler::Fail;
3844     case ARM::t2LDRHi12:
3845       Inst.setOpcode(ARM::t2PLDWi12);
3846       break;
3847     case ARM::t2LDRSBi12:
3848       Inst.setOpcode(ARM::t2PLIi12);
3849       break;
3850     default:
3851       break;
3852     }
3853   }
3854 
3855   switch (Inst.getOpcode()) {
3856   case ARM::t2PLDi12:
3857     break;
3858   case ARM::t2PLIi12:
3859     if (!hasV7Ops)
3860       return MCDisassembler::Fail;
3861     break;
3862   case ARM::t2PLDWi12:
3863       if (!hasV7Ops || !hasMP)
3864         return MCDisassembler::Fail;
3865       break;
3866   default:
3867     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3868       return MCDisassembler::Fail;
3869   }
3870 
3871   if (!Check(S, DecodeT2AddrModeImm12(Inst, imm, Address, Decoder)))
3872     return MCDisassembler::Fail;
3873   return S;
3874 }
3875 
3876 static DecodeStatus DecodeT2LoadT(MCInst &Inst, unsigned Insn,
3877                                 uint64_t Address, const void* Decoder) {
3878   DecodeStatus S = MCDisassembler::Success;
3879 
3880   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3881   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3882   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3883   imm |= (Rn << 9);
3884 
3885   if (Rn == 15) {
3886     switch (Inst.getOpcode()) {
3887     case ARM::t2LDRT:
3888       Inst.setOpcode(ARM::t2LDRpci);
3889       break;
3890     case ARM::t2LDRBT:
3891       Inst.setOpcode(ARM::t2LDRBpci);
3892       break;
3893     case ARM::t2LDRHT:
3894       Inst.setOpcode(ARM::t2LDRHpci);
3895       break;
3896     case ARM::t2LDRSBT:
3897       Inst.setOpcode(ARM::t2LDRSBpci);
3898       break;
3899     case ARM::t2LDRSHT:
3900       Inst.setOpcode(ARM::t2LDRSHpci);
3901       break;
3902     default:
3903       return MCDisassembler::Fail;
3904     }
3905     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3906   }
3907 
3908   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3909     return MCDisassembler::Fail;
3910   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
3911     return MCDisassembler::Fail;
3912   return S;
3913 }
3914 
3915 static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
3916                                 uint64_t Address, const void* Decoder) {
3917   DecodeStatus S = MCDisassembler::Success;
3918 
3919   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3920   unsigned U = fieldFromInstruction(Insn, 23, 1);
3921   int imm = fieldFromInstruction(Insn, 0, 12);
3922 
3923   const FeatureBitset &featureBits =
3924     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3925 
3926   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3927 
3928   if (Rt == 15) {
3929     switch (Inst.getOpcode()) {
3930       case ARM::t2LDRBpci:
3931       case ARM::t2LDRHpci:
3932         Inst.setOpcode(ARM::t2PLDpci);
3933         break;
3934       case ARM::t2LDRSBpci:
3935         Inst.setOpcode(ARM::t2PLIpci);
3936         break;
3937       case ARM::t2LDRSHpci:
3938         return MCDisassembler::Fail;
3939       default:
3940         break;
3941     }
3942   }
3943 
3944   switch(Inst.getOpcode()) {
3945   case ARM::t2PLDpci:
3946     break;
3947   case ARM::t2PLIpci:
3948     if (!hasV7Ops)
3949       return MCDisassembler::Fail;
3950     break;
3951   default:
3952     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3953       return MCDisassembler::Fail;
3954   }
3955 
3956   if (!U) {
3957     // Special case for #-0.
3958     if (imm == 0)
3959       imm = INT32_MIN;
3960     else
3961       imm = -imm;
3962   }
3963   Inst.addOperand(MCOperand::createImm(imm));
3964 
3965   return S;
3966 }
3967 
3968 static DecodeStatus DecodeT2Imm8S4(MCInst &Inst, unsigned Val,
3969                            uint64_t Address, const void *Decoder) {
3970   if (Val == 0)
3971     Inst.addOperand(MCOperand::createImm(INT32_MIN));
3972   else {
3973     int imm = Val & 0xFF;
3974 
3975     if (!(Val & 0x100)) imm *= -1;
3976     Inst.addOperand(MCOperand::createImm(imm * 4));
3977   }
3978 
3979   return MCDisassembler::Success;
3980 }
3981 
3982 static DecodeStatus DecodeT2Imm7S4(MCInst &Inst, unsigned Val, uint64_t Address,
3983                                    const void *Decoder) {
3984   if (Val == 0)
3985     Inst.addOperand(MCOperand::createImm(INT32_MIN));
3986   else {
3987     int imm = Val & 0x7F;
3988 
3989     if (!(Val & 0x80))
3990       imm *= -1;
3991     Inst.addOperand(MCOperand::createImm(imm * 4));
3992   }
3993 
3994   return MCDisassembler::Success;
3995 }
3996 
3997 static DecodeStatus DecodeT2AddrModeImm8s4(MCInst &Inst, unsigned Val,
3998                                    uint64_t Address, const void *Decoder) {
3999   DecodeStatus S = MCDisassembler::Success;
4000 
4001   unsigned Rn = fieldFromInstruction(Val, 9, 4);
4002   unsigned imm = fieldFromInstruction(Val, 0, 9);
4003 
4004   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4005     return MCDisassembler::Fail;
4006   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
4007     return MCDisassembler::Fail;
4008 
4009   return S;
4010 }
4011 
4012 static DecodeStatus DecodeT2AddrModeImm7s4(MCInst &Inst, unsigned Val,
4013                                            uint64_t Address,
4014                                            const void *Decoder) {
4015   DecodeStatus S = MCDisassembler::Success;
4016 
4017   unsigned Rn = fieldFromInstruction(Val, 8, 4);
4018   unsigned imm = fieldFromInstruction(Val, 0, 8);
4019 
4020   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
4021     return MCDisassembler::Fail;
4022   if (!Check(S, DecodeT2Imm7S4(Inst, imm, Address, Decoder)))
4023     return MCDisassembler::Fail;
4024 
4025   return S;
4026 }
4027 
4028 static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst &Inst,unsigned Val,
4029                                    uint64_t Address, const void *Decoder) {
4030   DecodeStatus S = MCDisassembler::Success;
4031 
4032   unsigned Rn = fieldFromInstruction(Val, 8, 4);
4033   unsigned imm = fieldFromInstruction(Val, 0, 8);
4034 
4035   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
4036     return MCDisassembler::Fail;
4037 
4038   Inst.addOperand(MCOperand::createImm(imm));
4039 
4040   return S;
4041 }
4042 
4043 static DecodeStatus DecodeT2Imm8(MCInst &Inst, unsigned Val,
4044                          uint64_t Address, const void *Decoder) {
4045   int imm = Val & 0xFF;
4046   if (Val == 0)
4047     imm = INT32_MIN;
4048   else if (!(Val & 0x100))
4049     imm *= -1;
4050   Inst.addOperand(MCOperand::createImm(imm));
4051 
4052   return MCDisassembler::Success;
4053 }
4054 
4055 static DecodeStatus DecodeT2AddrModeImm8(MCInst &Inst, unsigned Val,
4056                                  uint64_t Address, const void *Decoder) {
4057   DecodeStatus S = MCDisassembler::Success;
4058 
4059   unsigned Rn = fieldFromInstruction(Val, 9, 4);
4060   unsigned imm = fieldFromInstruction(Val, 0, 9);
4061 
4062   // Thumb stores cannot use PC as dest register.
4063   switch (Inst.getOpcode()) {
4064   case ARM::t2STRT:
4065   case ARM::t2STRBT:
4066   case ARM::t2STRHT:
4067   case ARM::t2STRi8:
4068   case ARM::t2STRHi8:
4069   case ARM::t2STRBi8:
4070     if (Rn == 15)
4071       return MCDisassembler::Fail;
4072     break;
4073   default:
4074     break;
4075   }
4076 
4077   // Some instructions always use an additive offset.
4078   switch (Inst.getOpcode()) {
4079     case ARM::t2LDRT:
4080     case ARM::t2LDRBT:
4081     case ARM::t2LDRHT:
4082     case ARM::t2LDRSBT:
4083     case ARM::t2LDRSHT:
4084     case ARM::t2STRT:
4085     case ARM::t2STRBT:
4086     case ARM::t2STRHT:
4087       imm |= 0x100;
4088       break;
4089     default:
4090       break;
4091   }
4092 
4093   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4094     return MCDisassembler::Fail;
4095   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
4096     return MCDisassembler::Fail;
4097 
4098   return S;
4099 }
4100 
4101 static DecodeStatus DecodeT2LdStPre(MCInst &Inst, unsigned Insn,
4102                                     uint64_t Address, const void *Decoder) {
4103   DecodeStatus S = MCDisassembler::Success;
4104 
4105   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4106   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4107   unsigned addr = fieldFromInstruction(Insn, 0, 8);
4108   addr |= fieldFromInstruction(Insn, 9, 1) << 8;
4109   addr |= Rn << 9;
4110   unsigned load = fieldFromInstruction(Insn, 20, 1);
4111 
4112   if (Rn == 15) {
4113     switch (Inst.getOpcode()) {
4114     case ARM::t2LDR_PRE:
4115     case ARM::t2LDR_POST:
4116       Inst.setOpcode(ARM::t2LDRpci);
4117       break;
4118     case ARM::t2LDRB_PRE:
4119     case ARM::t2LDRB_POST:
4120       Inst.setOpcode(ARM::t2LDRBpci);
4121       break;
4122     case ARM::t2LDRH_PRE:
4123     case ARM::t2LDRH_POST:
4124       Inst.setOpcode(ARM::t2LDRHpci);
4125       break;
4126     case ARM::t2LDRSB_PRE:
4127     case ARM::t2LDRSB_POST:
4128       if (Rt == 15)
4129         Inst.setOpcode(ARM::t2PLIpci);
4130       else
4131         Inst.setOpcode(ARM::t2LDRSBpci);
4132       break;
4133     case ARM::t2LDRSH_PRE:
4134     case ARM::t2LDRSH_POST:
4135       Inst.setOpcode(ARM::t2LDRSHpci);
4136       break;
4137     default:
4138       return MCDisassembler::Fail;
4139     }
4140     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
4141   }
4142 
4143   if (!load) {
4144     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4145       return MCDisassembler::Fail;
4146   }
4147 
4148   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4149     return MCDisassembler::Fail;
4150 
4151   if (load) {
4152     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4153       return MCDisassembler::Fail;
4154   }
4155 
4156   if (!Check(S, DecodeT2AddrModeImm8(Inst, addr, Address, Decoder)))
4157     return MCDisassembler::Fail;
4158 
4159   return S;
4160 }
4161 
4162 static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
4163                                   uint64_t Address, const void *Decoder) {
4164   DecodeStatus S = MCDisassembler::Success;
4165 
4166   unsigned Rn = fieldFromInstruction(Val, 13, 4);
4167   unsigned imm = fieldFromInstruction(Val, 0, 12);
4168 
4169   // Thumb stores cannot use PC as dest register.
4170   switch (Inst.getOpcode()) {
4171   case ARM::t2STRi12:
4172   case ARM::t2STRBi12:
4173   case ARM::t2STRHi12:
4174     if (Rn == 15)
4175       return MCDisassembler::Fail;
4176     break;
4177   default:
4178     break;
4179   }
4180 
4181   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4182     return MCDisassembler::Fail;
4183   Inst.addOperand(MCOperand::createImm(imm));
4184 
4185   return S;
4186 }
4187 
4188 static DecodeStatus DecodeThumbAddSPImm(MCInst &Inst, uint16_t Insn,
4189                                 uint64_t Address, const void *Decoder) {
4190   unsigned imm = fieldFromInstruction(Insn, 0, 7);
4191 
4192   Inst.addOperand(MCOperand::createReg(ARM::SP));
4193   Inst.addOperand(MCOperand::createReg(ARM::SP));
4194   Inst.addOperand(MCOperand::createImm(imm));
4195 
4196   return MCDisassembler::Success;
4197 }
4198 
4199 static DecodeStatus DecodeThumbAddSPReg(MCInst &Inst, uint16_t Insn,
4200                                 uint64_t Address, const void *Decoder) {
4201   DecodeStatus S = MCDisassembler::Success;
4202 
4203   if (Inst.getOpcode() == ARM::tADDrSP) {
4204     unsigned Rdm = fieldFromInstruction(Insn, 0, 3);
4205     Rdm |= fieldFromInstruction(Insn, 7, 1) << 3;
4206 
4207     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
4208     return MCDisassembler::Fail;
4209     Inst.addOperand(MCOperand::createReg(ARM::SP));
4210     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
4211     return MCDisassembler::Fail;
4212   } else if (Inst.getOpcode() == ARM::tADDspr) {
4213     unsigned Rm = fieldFromInstruction(Insn, 3, 4);
4214 
4215     Inst.addOperand(MCOperand::createReg(ARM::SP));
4216     Inst.addOperand(MCOperand::createReg(ARM::SP));
4217     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4218     return MCDisassembler::Fail;
4219   }
4220 
4221   return S;
4222 }
4223 
4224 static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
4225                            uint64_t Address, const void *Decoder) {
4226   unsigned imod = fieldFromInstruction(Insn, 4, 1) | 0x2;
4227   unsigned flags = fieldFromInstruction(Insn, 0, 3);
4228 
4229   Inst.addOperand(MCOperand::createImm(imod));
4230   Inst.addOperand(MCOperand::createImm(flags));
4231 
4232   return MCDisassembler::Success;
4233 }
4234 
4235 static DecodeStatus DecodePostIdxReg(MCInst &Inst, unsigned Insn,
4236                              uint64_t Address, const void *Decoder) {
4237   DecodeStatus S = MCDisassembler::Success;
4238   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4239   unsigned add = fieldFromInstruction(Insn, 4, 1);
4240 
4241   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
4242     return MCDisassembler::Fail;
4243   Inst.addOperand(MCOperand::createImm(add));
4244 
4245   return S;
4246 }
4247 
4248 static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Val,
4249                                  uint64_t Address, const void *Decoder) {
4250   // Val is passed in as S:J1:J2:imm10H:imm10L:'0'
4251   // Note only one trailing zero not two.  Also the J1 and J2 values are from
4252   // the encoded instruction.  So here change to I1 and I2 values via:
4253   // I1 = NOT(J1 EOR S);
4254   // I2 = NOT(J2 EOR S);
4255   // and build the imm32 with two trailing zeros as documented:
4256   // imm32 = SignExtend(S:I1:I2:imm10H:imm10L:'00', 32);
4257   unsigned S = (Val >> 23) & 1;
4258   unsigned J1 = (Val >> 22) & 1;
4259   unsigned J2 = (Val >> 21) & 1;
4260   unsigned I1 = !(J1 ^ S);
4261   unsigned I2 = !(J2 ^ S);
4262   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
4263   int imm32 = SignExtend32<25>(tmp << 1);
4264 
4265   if (!tryAddingSymbolicOperand(Address,
4266                                 (Address & ~2u) + imm32 + 4,
4267                                 true, 4, Inst, Decoder))
4268     Inst.addOperand(MCOperand::createImm(imm32));
4269   return MCDisassembler::Success;
4270 }
4271 
4272 static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Val,
4273                               uint64_t Address, const void *Decoder) {
4274   if (Val == 0xA || Val == 0xB)
4275     return MCDisassembler::Fail;
4276 
4277   const FeatureBitset &featureBits =
4278     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
4279 
4280   if (featureBits[ARM::HasV8Ops] && !(Val == 14 || Val == 15))
4281     return MCDisassembler::Fail;
4282 
4283   // For Armv8.1-M Mainline coprocessors matching 100x,101x or 111x should
4284   // decode as VFP/MVE instructions.
4285   if (featureBits[ARM::HasV8_1MMainlineOps] &&
4286       ((Val & 0xE) == 0x8 || (Val & 0xE) == 0xA ||
4287        (Val & 0xE) == 0xE))
4288     return MCDisassembler::Fail;
4289 
4290   Inst.addOperand(MCOperand::createImm(Val));
4291   return MCDisassembler::Success;
4292 }
4293 
4294 static DecodeStatus
4295 DecodeThumbTableBranch(MCInst &Inst, unsigned Insn,
4296                        uint64_t Address, const void *Decoder) {
4297   DecodeStatus S = MCDisassembler::Success;
4298 
4299   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4300   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4301 
4302   if (Rn == ARM::SP) S = MCDisassembler::SoftFail;
4303   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4304     return MCDisassembler::Fail;
4305   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
4306     return MCDisassembler::Fail;
4307   return S;
4308 }
4309 
4310 static DecodeStatus
4311 DecodeThumb2BCCInstruction(MCInst &Inst, unsigned Insn,
4312                            uint64_t Address, const void *Decoder) {
4313   DecodeStatus S = MCDisassembler::Success;
4314 
4315   unsigned pred = fieldFromInstruction(Insn, 22, 4);
4316   if (pred == 0xE || pred == 0xF) {
4317     unsigned opc = fieldFromInstruction(Insn, 4, 28);
4318     switch (opc) {
4319       default:
4320         return MCDisassembler::Fail;
4321       case 0xf3bf8f4:
4322         Inst.setOpcode(ARM::t2DSB);
4323         break;
4324       case 0xf3bf8f5:
4325         Inst.setOpcode(ARM::t2DMB);
4326         break;
4327       case 0xf3bf8f6:
4328         Inst.setOpcode(ARM::t2ISB);
4329         break;
4330     }
4331 
4332     unsigned imm = fieldFromInstruction(Insn, 0, 4);
4333     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
4334   }
4335 
4336   unsigned brtarget = fieldFromInstruction(Insn, 0, 11) << 1;
4337   brtarget |= fieldFromInstruction(Insn, 11, 1) << 19;
4338   brtarget |= fieldFromInstruction(Insn, 13, 1) << 18;
4339   brtarget |= fieldFromInstruction(Insn, 16, 6) << 12;
4340   brtarget |= fieldFromInstruction(Insn, 26, 1) << 20;
4341 
4342   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
4343     return MCDisassembler::Fail;
4344   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4345     return MCDisassembler::Fail;
4346 
4347   return S;
4348 }
4349 
4350 // Decode a shifted immediate operand.  These basically consist
4351 // of an 8-bit value, and a 4-bit directive that specifies either
4352 // a splat operation or a rotation.
4353 static DecodeStatus DecodeT2SOImm(MCInst &Inst, unsigned Val,
4354                           uint64_t Address, const void *Decoder) {
4355   unsigned ctrl = fieldFromInstruction(Val, 10, 2);
4356   if (ctrl == 0) {
4357     unsigned byte = fieldFromInstruction(Val, 8, 2);
4358     unsigned imm = fieldFromInstruction(Val, 0, 8);
4359     switch (byte) {
4360       case 0:
4361         Inst.addOperand(MCOperand::createImm(imm));
4362         break;
4363       case 1:
4364         Inst.addOperand(MCOperand::createImm((imm << 16) | imm));
4365         break;
4366       case 2:
4367         Inst.addOperand(MCOperand::createImm((imm << 24) | (imm << 8)));
4368         break;
4369       case 3:
4370         Inst.addOperand(MCOperand::createImm((imm << 24) | (imm << 16) |
4371                                              (imm << 8)  |  imm));
4372         break;
4373     }
4374   } else {
4375     unsigned unrot = fieldFromInstruction(Val, 0, 7) | 0x80;
4376     unsigned rot = fieldFromInstruction(Val, 7, 5);
4377     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
4378     Inst.addOperand(MCOperand::createImm(imm));
4379   }
4380 
4381   return MCDisassembler::Success;
4382 }
4383 
4384 static DecodeStatus
4385 DecodeThumbBCCTargetOperand(MCInst &Inst, unsigned Val,
4386                             uint64_t Address, const void *Decoder) {
4387   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<9>(Val<<1) + 4,
4388                                 true, 2, Inst, Decoder))
4389     Inst.addOperand(MCOperand::createImm(SignExtend32<9>(Val << 1)));
4390   return MCDisassembler::Success;
4391 }
4392 
4393 static DecodeStatus DecodeThumbBLTargetOperand(MCInst &Inst, unsigned Val,
4394                                                uint64_t Address,
4395                                                const void *Decoder) {
4396   // Val is passed in as S:J1:J2:imm10:imm11
4397   // Note no trailing zero after imm11.  Also the J1 and J2 values are from
4398   // the encoded instruction.  So here change to I1 and I2 values via:
4399   // I1 = NOT(J1 EOR S);
4400   // I2 = NOT(J2 EOR S);
4401   // and build the imm32 with one trailing zero as documented:
4402   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
4403   unsigned S = (Val >> 23) & 1;
4404   unsigned J1 = (Val >> 22) & 1;
4405   unsigned J2 = (Val >> 21) & 1;
4406   unsigned I1 = !(J1 ^ S);
4407   unsigned I2 = !(J2 ^ S);
4408   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
4409   int imm32 = SignExtend32<25>(tmp << 1);
4410 
4411   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
4412                                 true, 4, Inst, Decoder))
4413     Inst.addOperand(MCOperand::createImm(imm32));
4414   return MCDisassembler::Success;
4415 }
4416 
4417 static DecodeStatus DecodeMemBarrierOption(MCInst &Inst, unsigned Val,
4418                                    uint64_t Address, const void *Decoder) {
4419   if (Val & ~0xf)
4420     return MCDisassembler::Fail;
4421 
4422   Inst.addOperand(MCOperand::createImm(Val));
4423   return MCDisassembler::Success;
4424 }
4425 
4426 static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Val,
4427                                         uint64_t Address, const void *Decoder) {
4428   if (Val & ~0xf)
4429     return MCDisassembler::Fail;
4430 
4431   Inst.addOperand(MCOperand::createImm(Val));
4432   return MCDisassembler::Success;
4433 }
4434 
4435 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val,
4436                           uint64_t Address, const void *Decoder) {
4437   DecodeStatus S = MCDisassembler::Success;
4438   const FeatureBitset &FeatureBits =
4439     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
4440 
4441   if (FeatureBits[ARM::FeatureMClass]) {
4442     unsigned ValLow = Val & 0xff;
4443 
4444     // Validate the SYSm value first.
4445     switch (ValLow) {
4446     case  0: // apsr
4447     case  1: // iapsr
4448     case  2: // eapsr
4449     case  3: // xpsr
4450     case  5: // ipsr
4451     case  6: // epsr
4452     case  7: // iepsr
4453     case  8: // msp
4454     case  9: // psp
4455     case 16: // primask
4456     case 20: // control
4457       break;
4458     case 17: // basepri
4459     case 18: // basepri_max
4460     case 19: // faultmask
4461       if (!(FeatureBits[ARM::HasV7Ops]))
4462         // Values basepri, basepri_max and faultmask are only valid for v7m.
4463         return MCDisassembler::Fail;
4464       break;
4465     case 0x8a: // msplim_ns
4466     case 0x8b: // psplim_ns
4467     case 0x91: // basepri_ns
4468     case 0x93: // faultmask_ns
4469       if (!(FeatureBits[ARM::HasV8MMainlineOps]))
4470         return MCDisassembler::Fail;
4471       LLVM_FALLTHROUGH;
4472     case 10:   // msplim
4473     case 11:   // psplim
4474     case 0x88: // msp_ns
4475     case 0x89: // psp_ns
4476     case 0x90: // primask_ns
4477     case 0x94: // control_ns
4478     case 0x98: // sp_ns
4479       if (!(FeatureBits[ARM::Feature8MSecExt]))
4480         return MCDisassembler::Fail;
4481       break;
4482     default:
4483       // Architecturally defined as unpredictable
4484       S = MCDisassembler::SoftFail;
4485       break;
4486     }
4487 
4488     if (Inst.getOpcode() == ARM::t2MSR_M) {
4489       unsigned Mask = fieldFromInstruction(Val, 10, 2);
4490       if (!(FeatureBits[ARM::HasV7Ops])) {
4491         // The ARMv6-M MSR bits {11-10} can be only 0b10, other values are
4492         // unpredictable.
4493         if (Mask != 2)
4494           S = MCDisassembler::SoftFail;
4495       }
4496       else {
4497         // The ARMv7-M architecture stores an additional 2-bit mask value in
4498         // MSR bits {11-10}. The mask is used only with apsr, iapsr, eapsr and
4499         // xpsr, it has to be 0b10 in other cases. Bit mask{1} indicates if
4500         // the NZCVQ bits should be moved by the instruction. Bit mask{0}
4501         // indicates the move for the GE{3:0} bits, the mask{0} bit can be set
4502         // only if the processor includes the DSP extension.
4503         if (Mask == 0 || (Mask != 2 && ValLow > 3) ||
4504             (!(FeatureBits[ARM::FeatureDSP]) && (Mask & 1)))
4505           S = MCDisassembler::SoftFail;
4506       }
4507     }
4508   } else {
4509     // A/R class
4510     if (Val == 0)
4511       return MCDisassembler::Fail;
4512   }
4513   Inst.addOperand(MCOperand::createImm(Val));
4514   return S;
4515 }
4516 
4517 static DecodeStatus DecodeBankedReg(MCInst &Inst, unsigned Val,
4518                                     uint64_t Address, const void *Decoder) {
4519   unsigned R = fieldFromInstruction(Val, 5, 1);
4520   unsigned SysM = fieldFromInstruction(Val, 0, 5);
4521 
4522   // The table of encodings for these banked registers comes from B9.2.3 of the
4523   // ARM ARM. There are patterns, but nothing regular enough to make this logic
4524   // neater. So by fiat, these values are UNPREDICTABLE:
4525   if (!ARMBankedReg::lookupBankedRegByEncoding((R << 5) | SysM))
4526     return MCDisassembler::Fail;
4527 
4528   Inst.addOperand(MCOperand::createImm(Val));
4529   return MCDisassembler::Success;
4530 }
4531 
4532 static DecodeStatus DecodeDoubleRegLoad(MCInst &Inst, unsigned Insn,
4533                                         uint64_t Address, const void *Decoder) {
4534   DecodeStatus S = MCDisassembler::Success;
4535 
4536   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4537   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4538   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4539 
4540   if (Rn == 0xF)
4541     S = MCDisassembler::SoftFail;
4542 
4543   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
4544     return MCDisassembler::Fail;
4545   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4546     return MCDisassembler::Fail;
4547   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4548     return MCDisassembler::Fail;
4549 
4550   return S;
4551 }
4552 
4553 static DecodeStatus DecodeDoubleRegStore(MCInst &Inst, unsigned Insn,
4554                                          uint64_t Address,
4555                                          const void *Decoder) {
4556   DecodeStatus S = MCDisassembler::Success;
4557 
4558   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4559   unsigned Rt = fieldFromInstruction(Insn, 0, 4);
4560   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4561   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4562 
4563   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
4564     return MCDisassembler::Fail;
4565 
4566   if (Rn == 0xF || Rd == Rn || Rd == Rt || Rd == Rt+1)
4567     S = MCDisassembler::SoftFail;
4568 
4569   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
4570     return MCDisassembler::Fail;
4571   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4572     return MCDisassembler::Fail;
4573   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4574     return MCDisassembler::Fail;
4575 
4576   return S;
4577 }
4578 
4579 static DecodeStatus DecodeLDRPreImm(MCInst &Inst, unsigned Insn,
4580                             uint64_t Address, const void *Decoder) {
4581   DecodeStatus S = MCDisassembler::Success;
4582 
4583   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4584   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4585   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4586   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4587   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4588   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4589 
4590   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4591 
4592   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4593     return MCDisassembler::Fail;
4594   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4595     return MCDisassembler::Fail;
4596   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
4597     return MCDisassembler::Fail;
4598   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4599     return MCDisassembler::Fail;
4600 
4601   return S;
4602 }
4603 
4604 static DecodeStatus DecodeLDRPreReg(MCInst &Inst, unsigned Insn,
4605                             uint64_t Address, const void *Decoder) {
4606   DecodeStatus S = MCDisassembler::Success;
4607 
4608   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4609   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4610   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4611   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4612   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4613   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4614   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4615 
4616   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4617   if (Rm == 0xF) S = MCDisassembler::SoftFail;
4618 
4619   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4620     return MCDisassembler::Fail;
4621   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4622     return MCDisassembler::Fail;
4623   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
4624     return MCDisassembler::Fail;
4625   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4626     return MCDisassembler::Fail;
4627 
4628   return S;
4629 }
4630 
4631 static DecodeStatus DecodeSTRPreImm(MCInst &Inst, unsigned Insn,
4632                             uint64_t Address, const void *Decoder) {
4633   DecodeStatus S = MCDisassembler::Success;
4634 
4635   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4636   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4637   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4638   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4639   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4640   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4641 
4642   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4643 
4644   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4645     return MCDisassembler::Fail;
4646   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4647     return MCDisassembler::Fail;
4648   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
4649     return MCDisassembler::Fail;
4650   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4651     return MCDisassembler::Fail;
4652 
4653   return S;
4654 }
4655 
4656 static DecodeStatus DecodeSTRPreReg(MCInst &Inst, unsigned Insn,
4657                             uint64_t Address, const void *Decoder) {
4658   DecodeStatus S = MCDisassembler::Success;
4659 
4660   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4661   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4662   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4663   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4664   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4665   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4666 
4667   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4668 
4669   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4670     return MCDisassembler::Fail;
4671   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4672     return MCDisassembler::Fail;
4673   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
4674     return MCDisassembler::Fail;
4675   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4676     return MCDisassembler::Fail;
4677 
4678   return S;
4679 }
4680 
4681 static DecodeStatus DecodeVLD1LN(MCInst &Inst, unsigned Insn,
4682                          uint64_t Address, const void *Decoder) {
4683   DecodeStatus S = MCDisassembler::Success;
4684 
4685   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4686   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4687   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4688   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4689   unsigned size = fieldFromInstruction(Insn, 10, 2);
4690 
4691   unsigned align = 0;
4692   unsigned index = 0;
4693   switch (size) {
4694     default:
4695       return MCDisassembler::Fail;
4696     case 0:
4697       if (fieldFromInstruction(Insn, 4, 1))
4698         return MCDisassembler::Fail; // UNDEFINED
4699       index = fieldFromInstruction(Insn, 5, 3);
4700       break;
4701     case 1:
4702       if (fieldFromInstruction(Insn, 5, 1))
4703         return MCDisassembler::Fail; // UNDEFINED
4704       index = fieldFromInstruction(Insn, 6, 2);
4705       if (fieldFromInstruction(Insn, 4, 1))
4706         align = 2;
4707       break;
4708     case 2:
4709       if (fieldFromInstruction(Insn, 6, 1))
4710         return MCDisassembler::Fail; // UNDEFINED
4711       index = fieldFromInstruction(Insn, 7, 1);
4712 
4713       switch (fieldFromInstruction(Insn, 4, 2)) {
4714         case 0 :
4715           align = 0; break;
4716         case 3:
4717           align = 4; break;
4718         default:
4719           return MCDisassembler::Fail;
4720       }
4721       break;
4722   }
4723 
4724   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4725     return MCDisassembler::Fail;
4726   if (Rm != 0xF) { // Writeback
4727     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4728       return MCDisassembler::Fail;
4729   }
4730   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4731     return MCDisassembler::Fail;
4732   Inst.addOperand(MCOperand::createImm(align));
4733   if (Rm != 0xF) {
4734     if (Rm != 0xD) {
4735       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4736         return MCDisassembler::Fail;
4737     } else
4738       Inst.addOperand(MCOperand::createReg(0));
4739   }
4740 
4741   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4742     return MCDisassembler::Fail;
4743   Inst.addOperand(MCOperand::createImm(index));
4744 
4745   return S;
4746 }
4747 
4748 static DecodeStatus DecodeVST1LN(MCInst &Inst, unsigned Insn,
4749                          uint64_t Address, const void *Decoder) {
4750   DecodeStatus S = MCDisassembler::Success;
4751 
4752   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4753   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4754   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4755   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4756   unsigned size = fieldFromInstruction(Insn, 10, 2);
4757 
4758   unsigned align = 0;
4759   unsigned index = 0;
4760   switch (size) {
4761     default:
4762       return MCDisassembler::Fail;
4763     case 0:
4764       if (fieldFromInstruction(Insn, 4, 1))
4765         return MCDisassembler::Fail; // UNDEFINED
4766       index = fieldFromInstruction(Insn, 5, 3);
4767       break;
4768     case 1:
4769       if (fieldFromInstruction(Insn, 5, 1))
4770         return MCDisassembler::Fail; // UNDEFINED
4771       index = fieldFromInstruction(Insn, 6, 2);
4772       if (fieldFromInstruction(Insn, 4, 1))
4773         align = 2;
4774       break;
4775     case 2:
4776       if (fieldFromInstruction(Insn, 6, 1))
4777         return MCDisassembler::Fail; // UNDEFINED
4778       index = fieldFromInstruction(Insn, 7, 1);
4779 
4780       switch (fieldFromInstruction(Insn, 4, 2)) {
4781         case 0:
4782           align = 0; break;
4783         case 3:
4784           align = 4; break;
4785         default:
4786           return MCDisassembler::Fail;
4787       }
4788       break;
4789   }
4790 
4791   if (Rm != 0xF) { // Writeback
4792     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4793     return MCDisassembler::Fail;
4794   }
4795   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4796     return MCDisassembler::Fail;
4797   Inst.addOperand(MCOperand::createImm(align));
4798   if (Rm != 0xF) {
4799     if (Rm != 0xD) {
4800       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4801     return MCDisassembler::Fail;
4802     } else
4803       Inst.addOperand(MCOperand::createReg(0));
4804   }
4805 
4806   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4807     return MCDisassembler::Fail;
4808   Inst.addOperand(MCOperand::createImm(index));
4809 
4810   return S;
4811 }
4812 
4813 static DecodeStatus DecodeVLD2LN(MCInst &Inst, unsigned Insn,
4814                          uint64_t Address, const void *Decoder) {
4815   DecodeStatus S = MCDisassembler::Success;
4816 
4817   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4818   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4819   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4820   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4821   unsigned size = fieldFromInstruction(Insn, 10, 2);
4822 
4823   unsigned align = 0;
4824   unsigned index = 0;
4825   unsigned inc = 1;
4826   switch (size) {
4827     default:
4828       return MCDisassembler::Fail;
4829     case 0:
4830       index = fieldFromInstruction(Insn, 5, 3);
4831       if (fieldFromInstruction(Insn, 4, 1))
4832         align = 2;
4833       break;
4834     case 1:
4835       index = fieldFromInstruction(Insn, 6, 2);
4836       if (fieldFromInstruction(Insn, 4, 1))
4837         align = 4;
4838       if (fieldFromInstruction(Insn, 5, 1))
4839         inc = 2;
4840       break;
4841     case 2:
4842       if (fieldFromInstruction(Insn, 5, 1))
4843         return MCDisassembler::Fail; // UNDEFINED
4844       index = fieldFromInstruction(Insn, 7, 1);
4845       if (fieldFromInstruction(Insn, 4, 1) != 0)
4846         align = 8;
4847       if (fieldFromInstruction(Insn, 6, 1))
4848         inc = 2;
4849       break;
4850   }
4851 
4852   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4853     return MCDisassembler::Fail;
4854   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4855     return MCDisassembler::Fail;
4856   if (Rm != 0xF) { // Writeback
4857     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4858       return MCDisassembler::Fail;
4859   }
4860   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4861     return MCDisassembler::Fail;
4862   Inst.addOperand(MCOperand::createImm(align));
4863   if (Rm != 0xF) {
4864     if (Rm != 0xD) {
4865       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4866         return MCDisassembler::Fail;
4867     } else
4868       Inst.addOperand(MCOperand::createReg(0));
4869   }
4870 
4871   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4872     return MCDisassembler::Fail;
4873   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4874     return MCDisassembler::Fail;
4875   Inst.addOperand(MCOperand::createImm(index));
4876 
4877   return S;
4878 }
4879 
4880 static DecodeStatus DecodeVST2LN(MCInst &Inst, unsigned Insn,
4881                          uint64_t Address, const void *Decoder) {
4882   DecodeStatus S = MCDisassembler::Success;
4883 
4884   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4885   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4886   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4887   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4888   unsigned size = fieldFromInstruction(Insn, 10, 2);
4889 
4890   unsigned align = 0;
4891   unsigned index = 0;
4892   unsigned inc = 1;
4893   switch (size) {
4894     default:
4895       return MCDisassembler::Fail;
4896     case 0:
4897       index = fieldFromInstruction(Insn, 5, 3);
4898       if (fieldFromInstruction(Insn, 4, 1))
4899         align = 2;
4900       break;
4901     case 1:
4902       index = fieldFromInstruction(Insn, 6, 2);
4903       if (fieldFromInstruction(Insn, 4, 1))
4904         align = 4;
4905       if (fieldFromInstruction(Insn, 5, 1))
4906         inc = 2;
4907       break;
4908     case 2:
4909       if (fieldFromInstruction(Insn, 5, 1))
4910         return MCDisassembler::Fail; // UNDEFINED
4911       index = fieldFromInstruction(Insn, 7, 1);
4912       if (fieldFromInstruction(Insn, 4, 1) != 0)
4913         align = 8;
4914       if (fieldFromInstruction(Insn, 6, 1))
4915         inc = 2;
4916       break;
4917   }
4918 
4919   if (Rm != 0xF) { // Writeback
4920     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4921       return MCDisassembler::Fail;
4922   }
4923   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4924     return MCDisassembler::Fail;
4925   Inst.addOperand(MCOperand::createImm(align));
4926   if (Rm != 0xF) {
4927     if (Rm != 0xD) {
4928       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4929         return MCDisassembler::Fail;
4930     } else
4931       Inst.addOperand(MCOperand::createReg(0));
4932   }
4933 
4934   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4935     return MCDisassembler::Fail;
4936   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4937     return MCDisassembler::Fail;
4938   Inst.addOperand(MCOperand::createImm(index));
4939 
4940   return S;
4941 }
4942 
4943 static DecodeStatus DecodeVLD3LN(MCInst &Inst, unsigned Insn,
4944                          uint64_t Address, const void *Decoder) {
4945   DecodeStatus S = MCDisassembler::Success;
4946 
4947   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4948   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4949   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4950   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4951   unsigned size = fieldFromInstruction(Insn, 10, 2);
4952 
4953   unsigned align = 0;
4954   unsigned index = 0;
4955   unsigned inc = 1;
4956   switch (size) {
4957     default:
4958       return MCDisassembler::Fail;
4959     case 0:
4960       if (fieldFromInstruction(Insn, 4, 1))
4961         return MCDisassembler::Fail; // UNDEFINED
4962       index = fieldFromInstruction(Insn, 5, 3);
4963       break;
4964     case 1:
4965       if (fieldFromInstruction(Insn, 4, 1))
4966         return MCDisassembler::Fail; // UNDEFINED
4967       index = fieldFromInstruction(Insn, 6, 2);
4968       if (fieldFromInstruction(Insn, 5, 1))
4969         inc = 2;
4970       break;
4971     case 2:
4972       if (fieldFromInstruction(Insn, 4, 2))
4973         return MCDisassembler::Fail; // UNDEFINED
4974       index = fieldFromInstruction(Insn, 7, 1);
4975       if (fieldFromInstruction(Insn, 6, 1))
4976         inc = 2;
4977       break;
4978   }
4979 
4980   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4981     return MCDisassembler::Fail;
4982   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4983     return MCDisassembler::Fail;
4984   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4985     return MCDisassembler::Fail;
4986 
4987   if (Rm != 0xF) { // Writeback
4988     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4989     return MCDisassembler::Fail;
4990   }
4991   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4992     return MCDisassembler::Fail;
4993   Inst.addOperand(MCOperand::createImm(align));
4994   if (Rm != 0xF) {
4995     if (Rm != 0xD) {
4996       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4997     return MCDisassembler::Fail;
4998     } else
4999       Inst.addOperand(MCOperand::createReg(0));
5000   }
5001 
5002   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
5003     return MCDisassembler::Fail;
5004   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
5005     return MCDisassembler::Fail;
5006   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
5007     return MCDisassembler::Fail;
5008   Inst.addOperand(MCOperand::createImm(index));
5009 
5010   return S;
5011 }
5012 
5013 static DecodeStatus DecodeVST3LN(MCInst &Inst, unsigned Insn,
5014                          uint64_t Address, const void *Decoder) {
5015   DecodeStatus S = MCDisassembler::Success;
5016 
5017   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5018   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
5019   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
5020   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
5021   unsigned size = fieldFromInstruction(Insn, 10, 2);
5022 
5023   unsigned align = 0;
5024   unsigned index = 0;
5025   unsigned inc = 1;
5026   switch (size) {
5027     default:
5028       return MCDisassembler::Fail;
5029     case 0:
5030       if (fieldFromInstruction(Insn, 4, 1))
5031         return MCDisassembler::Fail; // UNDEFINED
5032       index = fieldFromInstruction(Insn, 5, 3);
5033       break;
5034     case 1:
5035       if (fieldFromInstruction(Insn, 4, 1))
5036         return MCDisassembler::Fail; // UNDEFINED
5037       index = fieldFromInstruction(Insn, 6, 2);
5038       if (fieldFromInstruction(Insn, 5, 1))
5039         inc = 2;
5040       break;
5041     case 2:
5042       if (fieldFromInstruction(Insn, 4, 2))
5043         return MCDisassembler::Fail; // UNDEFINED
5044       index = fieldFromInstruction(Insn, 7, 1);
5045       if (fieldFromInstruction(Insn, 6, 1))
5046         inc = 2;
5047       break;
5048   }
5049 
5050   if (Rm != 0xF) { // Writeback
5051     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5052     return MCDisassembler::Fail;
5053   }
5054   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5055     return MCDisassembler::Fail;
5056   Inst.addOperand(MCOperand::createImm(align));
5057   if (Rm != 0xF) {
5058     if (Rm != 0xD) {
5059       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
5060     return MCDisassembler::Fail;
5061     } else
5062       Inst.addOperand(MCOperand::createReg(0));
5063   }
5064 
5065   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
5066     return MCDisassembler::Fail;
5067   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
5068     return MCDisassembler::Fail;
5069   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
5070     return MCDisassembler::Fail;
5071   Inst.addOperand(MCOperand::createImm(index));
5072 
5073   return S;
5074 }
5075 
5076 static DecodeStatus DecodeVLD4LN(MCInst &Inst, unsigned Insn,
5077                          uint64_t Address, const void *Decoder) {
5078   DecodeStatus S = MCDisassembler::Success;
5079 
5080   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5081   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
5082   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
5083   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
5084   unsigned size = fieldFromInstruction(Insn, 10, 2);
5085 
5086   unsigned align = 0;
5087   unsigned index = 0;
5088   unsigned inc = 1;
5089   switch (size) {
5090     default:
5091       return MCDisassembler::Fail;
5092     case 0:
5093       if (fieldFromInstruction(Insn, 4, 1))
5094         align = 4;
5095       index = fieldFromInstruction(Insn, 5, 3);
5096       break;
5097     case 1:
5098       if (fieldFromInstruction(Insn, 4, 1))
5099         align = 8;
5100       index = fieldFromInstruction(Insn, 6, 2);
5101       if (fieldFromInstruction(Insn, 5, 1))
5102         inc = 2;
5103       break;
5104     case 2:
5105       switch (fieldFromInstruction(Insn, 4, 2)) {
5106         case 0:
5107           align = 0; break;
5108         case 3:
5109           return MCDisassembler::Fail;
5110         default:
5111           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
5112       }
5113 
5114       index = fieldFromInstruction(Insn, 7, 1);
5115       if (fieldFromInstruction(Insn, 6, 1))
5116         inc = 2;
5117       break;
5118   }
5119 
5120   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
5121     return MCDisassembler::Fail;
5122   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
5123     return MCDisassembler::Fail;
5124   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
5125     return MCDisassembler::Fail;
5126   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
5127     return MCDisassembler::Fail;
5128 
5129   if (Rm != 0xF) { // Writeback
5130     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5131       return MCDisassembler::Fail;
5132   }
5133   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5134     return MCDisassembler::Fail;
5135   Inst.addOperand(MCOperand::createImm(align));
5136   if (Rm != 0xF) {
5137     if (Rm != 0xD) {
5138       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
5139         return MCDisassembler::Fail;
5140     } else
5141       Inst.addOperand(MCOperand::createReg(0));
5142   }
5143 
5144   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
5145     return MCDisassembler::Fail;
5146   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
5147     return MCDisassembler::Fail;
5148   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
5149     return MCDisassembler::Fail;
5150   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
5151     return MCDisassembler::Fail;
5152   Inst.addOperand(MCOperand::createImm(index));
5153 
5154   return S;
5155 }
5156 
5157 static DecodeStatus DecodeVST4LN(MCInst &Inst, unsigned Insn,
5158                          uint64_t Address, const void *Decoder) {
5159   DecodeStatus S = MCDisassembler::Success;
5160 
5161   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5162   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
5163   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
5164   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
5165   unsigned size = fieldFromInstruction(Insn, 10, 2);
5166 
5167   unsigned align = 0;
5168   unsigned index = 0;
5169   unsigned inc = 1;
5170   switch (size) {
5171     default:
5172       return MCDisassembler::Fail;
5173     case 0:
5174       if (fieldFromInstruction(Insn, 4, 1))
5175         align = 4;
5176       index = fieldFromInstruction(Insn, 5, 3);
5177       break;
5178     case 1:
5179       if (fieldFromInstruction(Insn, 4, 1))
5180         align = 8;
5181       index = fieldFromInstruction(Insn, 6, 2);
5182       if (fieldFromInstruction(Insn, 5, 1))
5183         inc = 2;
5184       break;
5185     case 2:
5186       switch (fieldFromInstruction(Insn, 4, 2)) {
5187         case 0:
5188           align = 0; break;
5189         case 3:
5190           return MCDisassembler::Fail;
5191         default:
5192           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
5193       }
5194 
5195       index = fieldFromInstruction(Insn, 7, 1);
5196       if (fieldFromInstruction(Insn, 6, 1))
5197         inc = 2;
5198       break;
5199   }
5200 
5201   if (Rm != 0xF) { // Writeback
5202     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5203     return MCDisassembler::Fail;
5204   }
5205   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5206     return MCDisassembler::Fail;
5207   Inst.addOperand(MCOperand::createImm(align));
5208   if (Rm != 0xF) {
5209     if (Rm != 0xD) {
5210       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
5211     return MCDisassembler::Fail;
5212     } else
5213       Inst.addOperand(MCOperand::createReg(0));
5214   }
5215 
5216   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
5217     return MCDisassembler::Fail;
5218   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
5219     return MCDisassembler::Fail;
5220   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
5221     return MCDisassembler::Fail;
5222   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
5223     return MCDisassembler::Fail;
5224   Inst.addOperand(MCOperand::createImm(index));
5225 
5226   return S;
5227 }
5228 
5229 static DecodeStatus DecodeVMOVSRR(MCInst &Inst, unsigned Insn,
5230                                   uint64_t Address, const void *Decoder) {
5231   DecodeStatus S = MCDisassembler::Success;
5232   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
5233   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
5234   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
5235   unsigned pred = fieldFromInstruction(Insn, 28, 4);
5236   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
5237 
5238   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
5239     S = MCDisassembler::SoftFail;
5240 
5241   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
5242     return MCDisassembler::Fail;
5243   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
5244     return MCDisassembler::Fail;
5245   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
5246     return MCDisassembler::Fail;
5247   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
5248     return MCDisassembler::Fail;
5249   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5250     return MCDisassembler::Fail;
5251 
5252   return S;
5253 }
5254 
5255 static DecodeStatus DecodeVMOVRRS(MCInst &Inst, unsigned Insn,
5256                                   uint64_t Address, const void *Decoder) {
5257   DecodeStatus S = MCDisassembler::Success;
5258   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
5259   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
5260   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
5261   unsigned pred = fieldFromInstruction(Insn, 28, 4);
5262   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
5263 
5264   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
5265     S = MCDisassembler::SoftFail;
5266 
5267   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
5268     return MCDisassembler::Fail;
5269   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
5270     return MCDisassembler::Fail;
5271   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
5272     return MCDisassembler::Fail;
5273   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
5274     return MCDisassembler::Fail;
5275   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5276     return MCDisassembler::Fail;
5277 
5278   return S;
5279 }
5280 
5281 static DecodeStatus DecodeIT(MCInst &Inst, unsigned Insn,
5282                              uint64_t Address, const void *Decoder) {
5283   DecodeStatus S = MCDisassembler::Success;
5284   unsigned pred = fieldFromInstruction(Insn, 4, 4);
5285   unsigned mask = fieldFromInstruction(Insn, 0, 4);
5286 
5287   if (pred == 0xF) {
5288     pred = 0xE;
5289     S = MCDisassembler::SoftFail;
5290   }
5291 
5292   if (mask == 0x0)
5293     return MCDisassembler::Fail;
5294 
5295   // IT masks are encoded as a sequence of replacement low-order bits
5296   // for the condition code. So if the low bit of the starting
5297   // condition code is 1, then we have to flip all the bits above the
5298   // terminating bit (which is the lowest 1 bit).
5299   if (pred & 1) {
5300     unsigned LowBit = mask & -mask;
5301     unsigned BitsAboveLowBit = 0xF & (-LowBit << 1);
5302     mask ^= BitsAboveLowBit;
5303   }
5304 
5305   Inst.addOperand(MCOperand::createImm(pred));
5306   Inst.addOperand(MCOperand::createImm(mask));
5307   return S;
5308 }
5309 
5310 static DecodeStatus
5311 DecodeT2LDRDPreInstruction(MCInst &Inst, unsigned Insn,
5312                            uint64_t Address, const void *Decoder) {
5313   DecodeStatus S = MCDisassembler::Success;
5314 
5315   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
5316   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
5317   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5318   unsigned addr = fieldFromInstruction(Insn, 0, 8);
5319   unsigned W = fieldFromInstruction(Insn, 21, 1);
5320   unsigned U = fieldFromInstruction(Insn, 23, 1);
5321   unsigned P = fieldFromInstruction(Insn, 24, 1);
5322   bool writeback = (W == 1) | (P == 0);
5323 
5324   addr |= (U << 8) | (Rn << 9);
5325 
5326   if (writeback && (Rn == Rt || Rn == Rt2))
5327     Check(S, MCDisassembler::SoftFail);
5328   if (Rt == Rt2)
5329     Check(S, MCDisassembler::SoftFail);
5330 
5331   // Rt
5332   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
5333     return MCDisassembler::Fail;
5334   // Rt2
5335   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
5336     return MCDisassembler::Fail;
5337   // Writeback operand
5338   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
5339     return MCDisassembler::Fail;
5340   // addr
5341   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
5342     return MCDisassembler::Fail;
5343 
5344   return S;
5345 }
5346 
5347 static DecodeStatus
5348 DecodeT2STRDPreInstruction(MCInst &Inst, unsigned Insn,
5349                            uint64_t Address, const void *Decoder) {
5350   DecodeStatus S = MCDisassembler::Success;
5351 
5352   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
5353   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
5354   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5355   unsigned addr = fieldFromInstruction(Insn, 0, 8);
5356   unsigned W = fieldFromInstruction(Insn, 21, 1);
5357   unsigned U = fieldFromInstruction(Insn, 23, 1);
5358   unsigned P = fieldFromInstruction(Insn, 24, 1);
5359   bool writeback = (W == 1) | (P == 0);
5360 
5361   addr |= (U << 8) | (Rn << 9);
5362 
5363   if (writeback && (Rn == Rt || Rn == Rt2))
5364     Check(S, MCDisassembler::SoftFail);
5365 
5366   // Writeback operand
5367   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
5368     return MCDisassembler::Fail;
5369   // Rt
5370   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
5371     return MCDisassembler::Fail;
5372   // Rt2
5373   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
5374     return MCDisassembler::Fail;
5375   // addr
5376   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
5377     return MCDisassembler::Fail;
5378 
5379   return S;
5380 }
5381 
5382 static DecodeStatus DecodeT2Adr(MCInst &Inst, uint32_t Insn,
5383                                 uint64_t Address, const void *Decoder) {
5384   unsigned sign1 = fieldFromInstruction(Insn, 21, 1);
5385   unsigned sign2 = fieldFromInstruction(Insn, 23, 1);
5386   if (sign1 != sign2) return MCDisassembler::Fail;
5387 
5388   unsigned Val = fieldFromInstruction(Insn, 0, 8);
5389   Val |= fieldFromInstruction(Insn, 12, 3) << 8;
5390   Val |= fieldFromInstruction(Insn, 26, 1) << 11;
5391   Val |= sign1 << 12;
5392   Inst.addOperand(MCOperand::createImm(SignExtend32<13>(Val)));
5393 
5394   return MCDisassembler::Success;
5395 }
5396 
5397 static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, uint32_t Val,
5398                                               uint64_t Address,
5399                                               const void *Decoder) {
5400   DecodeStatus S = MCDisassembler::Success;
5401 
5402   // Shift of "asr #32" is not allowed in Thumb2 mode.
5403   if (Val == 0x20) S = MCDisassembler::Fail;
5404   Inst.addOperand(MCOperand::createImm(Val));
5405   return S;
5406 }
5407 
5408 static DecodeStatus DecodeSwap(MCInst &Inst, unsigned Insn,
5409                                uint64_t Address, const void *Decoder) {
5410   unsigned Rt   = fieldFromInstruction(Insn, 12, 4);
5411   unsigned Rt2  = fieldFromInstruction(Insn, 0,  4);
5412   unsigned Rn   = fieldFromInstruction(Insn, 16, 4);
5413   unsigned pred = fieldFromInstruction(Insn, 28, 4);
5414 
5415   if (pred == 0xF)
5416     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
5417 
5418   DecodeStatus S = MCDisassembler::Success;
5419 
5420   if (Rt == Rn || Rn == Rt2)
5421     S = MCDisassembler::SoftFail;
5422 
5423   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5424     return MCDisassembler::Fail;
5425   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5426     return MCDisassembler::Fail;
5427   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
5428     return MCDisassembler::Fail;
5429   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5430     return MCDisassembler::Fail;
5431 
5432   return S;
5433 }
5434 
5435 static DecodeStatus DecodeVCVTD(MCInst &Inst, unsigned Insn,
5436                                 uint64_t Address, const void *Decoder) {
5437   const FeatureBitset &featureBits =
5438       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5439   bool hasFullFP16 = featureBits[ARM::FeatureFullFP16];
5440 
5441   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5442   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5443   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5444   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5445   unsigned imm = fieldFromInstruction(Insn, 16, 6);
5446   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
5447   unsigned op = fieldFromInstruction(Insn, 5, 1);
5448 
5449   DecodeStatus S = MCDisassembler::Success;
5450 
5451   // If the top 3 bits of imm are clear, this is a VMOV (immediate)
5452   if (!(imm & 0x38)) {
5453     if (cmode == 0xF) {
5454       if (op == 1) return MCDisassembler::Fail;
5455       Inst.setOpcode(ARM::VMOVv2f32);
5456     }
5457     if (hasFullFP16) {
5458       if (cmode == 0xE) {
5459         if (op == 1) {
5460           Inst.setOpcode(ARM::VMOVv1i64);
5461         } else {
5462           Inst.setOpcode(ARM::VMOVv8i8);
5463         }
5464       }
5465       if (cmode == 0xD) {
5466         if (op == 1) {
5467           Inst.setOpcode(ARM::VMVNv2i32);
5468         } else {
5469           Inst.setOpcode(ARM::VMOVv2i32);
5470         }
5471       }
5472       if (cmode == 0xC) {
5473         if (op == 1) {
5474           Inst.setOpcode(ARM::VMVNv2i32);
5475         } else {
5476           Inst.setOpcode(ARM::VMOVv2i32);
5477         }
5478       }
5479     }
5480     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
5481   }
5482 
5483   if (!(imm & 0x20)) return MCDisassembler::Fail;
5484 
5485   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
5486     return MCDisassembler::Fail;
5487   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
5488     return MCDisassembler::Fail;
5489   Inst.addOperand(MCOperand::createImm(64 - imm));
5490 
5491   return S;
5492 }
5493 
5494 static DecodeStatus DecodeVCVTQ(MCInst &Inst, unsigned Insn,
5495                                 uint64_t Address, const void *Decoder) {
5496   const FeatureBitset &featureBits =
5497       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5498   bool hasFullFP16 = featureBits[ARM::FeatureFullFP16];
5499 
5500   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5501   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5502   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5503   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5504   unsigned imm = fieldFromInstruction(Insn, 16, 6);
5505   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
5506   unsigned op = fieldFromInstruction(Insn, 5, 1);
5507 
5508   DecodeStatus S = MCDisassembler::Success;
5509 
5510   // If the top 3 bits of imm are clear, this is a VMOV (immediate)
5511   if (!(imm & 0x38)) {
5512     if (cmode == 0xF) {
5513       if (op == 1) return MCDisassembler::Fail;
5514       Inst.setOpcode(ARM::VMOVv4f32);
5515     }
5516     if (hasFullFP16) {
5517       if (cmode == 0xE) {
5518         if (op == 1) {
5519           Inst.setOpcode(ARM::VMOVv2i64);
5520         } else {
5521           Inst.setOpcode(ARM::VMOVv16i8);
5522         }
5523       }
5524       if (cmode == 0xD) {
5525         if (op == 1) {
5526           Inst.setOpcode(ARM::VMVNv4i32);
5527         } else {
5528           Inst.setOpcode(ARM::VMOVv4i32);
5529         }
5530       }
5531       if (cmode == 0xC) {
5532         if (op == 1) {
5533           Inst.setOpcode(ARM::VMVNv4i32);
5534         } else {
5535           Inst.setOpcode(ARM::VMOVv4i32);
5536         }
5537       }
5538     }
5539     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
5540   }
5541 
5542   if (!(imm & 0x20)) return MCDisassembler::Fail;
5543 
5544   if (!Check(S, DecodeQPRRegisterClass(Inst, Vd, Address, Decoder)))
5545     return MCDisassembler::Fail;
5546   if (!Check(S, DecodeQPRRegisterClass(Inst, Vm, Address, Decoder)))
5547     return MCDisassembler::Fail;
5548   Inst.addOperand(MCOperand::createImm(64 - imm));
5549 
5550   return S;
5551 }
5552 
5553 static DecodeStatus DecodeNEONComplexLane64Instruction(MCInst &Inst,
5554                                                        unsigned Insn,
5555                                                        uint64_t Address,
5556                                                        const void *Decoder) {
5557   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5558   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5559   unsigned Vn = (fieldFromInstruction(Insn, 16, 4) << 0);
5560   Vn |= (fieldFromInstruction(Insn, 7, 1) << 4);
5561   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5562   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5563   unsigned q = (fieldFromInstruction(Insn, 6, 1) << 0);
5564   unsigned rotate = (fieldFromInstruction(Insn, 20, 2) << 0);
5565 
5566   DecodeStatus S = MCDisassembler::Success;
5567 
5568   auto DestRegDecoder = q ? DecodeQPRRegisterClass : DecodeDPRRegisterClass;
5569 
5570   if (!Check(S, DestRegDecoder(Inst, Vd, Address, Decoder)))
5571     return MCDisassembler::Fail;
5572   if (!Check(S, DestRegDecoder(Inst, Vd, Address, Decoder)))
5573     return MCDisassembler::Fail;
5574   if (!Check(S, DestRegDecoder(Inst, Vn, Address, Decoder)))
5575     return MCDisassembler::Fail;
5576   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
5577     return MCDisassembler::Fail;
5578   // The lane index does not have any bits in the encoding, because it can only
5579   // be 0.
5580   Inst.addOperand(MCOperand::createImm(0));
5581   Inst.addOperand(MCOperand::createImm(rotate));
5582 
5583   return S;
5584 }
5585 
5586 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
5587                                 uint64_t Address, const void *Decoder) {
5588   DecodeStatus S = MCDisassembler::Success;
5589 
5590   unsigned Rn = fieldFromInstruction(Val, 16, 4);
5591   unsigned Rt = fieldFromInstruction(Val, 12, 4);
5592   unsigned Rm = fieldFromInstruction(Val, 0, 4);
5593   Rm |= (fieldFromInstruction(Val, 23, 1) << 4);
5594   unsigned Cond = fieldFromInstruction(Val, 28, 4);
5595 
5596   if (fieldFromInstruction(Val, 8, 4) != 0 || Rn == Rt)
5597     S = MCDisassembler::SoftFail;
5598 
5599   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5600     return MCDisassembler::Fail;
5601   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
5602     return MCDisassembler::Fail;
5603   if (!Check(S, DecodeAddrMode7Operand(Inst, Rn, Address, Decoder)))
5604     return MCDisassembler::Fail;
5605   if (!Check(S, DecodePostIdxReg(Inst, Rm, Address, Decoder)))
5606     return MCDisassembler::Fail;
5607   if (!Check(S, DecodePredicateOperand(Inst, Cond, Address, Decoder)))
5608     return MCDisassembler::Fail;
5609 
5610   return S;
5611 }
5612 
5613 static DecodeStatus DecoderForMRRC2AndMCRR2(MCInst &Inst, unsigned Val,
5614                                             uint64_t Address, const void *Decoder) {
5615   DecodeStatus S = MCDisassembler::Success;
5616 
5617   unsigned CRm = fieldFromInstruction(Val, 0, 4);
5618   unsigned opc1 = fieldFromInstruction(Val, 4, 4);
5619   unsigned cop = fieldFromInstruction(Val, 8, 4);
5620   unsigned Rt = fieldFromInstruction(Val, 12, 4);
5621   unsigned Rt2 = fieldFromInstruction(Val, 16, 4);
5622 
5623   if ((cop & ~0x1) == 0xa)
5624     return MCDisassembler::Fail;
5625 
5626   if (Rt == Rt2)
5627     S = MCDisassembler::SoftFail;
5628 
5629   // We have to check if the instruction is MRRC2
5630   // or MCRR2 when constructing the operands for
5631   // Inst. Reason is because MRRC2 stores to two
5632   // registers so it's tablegen desc has has two
5633   // outputs whereas MCRR doesn't store to any
5634   // registers so all of it's operands are listed
5635   // as inputs, therefore the operand order for
5636   // MRRC2 needs to be [Rt, Rt2, cop, opc1, CRm]
5637   // and MCRR2 operand order is [cop, opc1, Rt, Rt2, CRm]
5638 
5639   if (Inst.getOpcode() == ARM::MRRC2) {
5640     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5641       return MCDisassembler::Fail;
5642     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5643       return MCDisassembler::Fail;
5644   }
5645   Inst.addOperand(MCOperand::createImm(cop));
5646   Inst.addOperand(MCOperand::createImm(opc1));
5647   if (Inst.getOpcode() == ARM::MCRR2) {
5648     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5649       return MCDisassembler::Fail;
5650     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5651       return MCDisassembler::Fail;
5652   }
5653   Inst.addOperand(MCOperand::createImm(CRm));
5654 
5655   return S;
5656 }
5657 
5658 static DecodeStatus DecodeForVMRSandVMSR(MCInst &Inst, unsigned Val,
5659                                          uint64_t Address,
5660                                          const void *Decoder) {
5661   const FeatureBitset &featureBits =
5662       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5663   DecodeStatus S = MCDisassembler::Success;
5664 
5665   // Add explicit operand for the destination sysreg, for cases where
5666   // we have to model it for code generation purposes.
5667   switch (Inst.getOpcode()) {
5668   case ARM::VMSR_FPSCR_NZCVQC:
5669     Inst.addOperand(MCOperand::createReg(ARM::FPSCR_NZCV));
5670     break;
5671   case ARM::VMSR_P0:
5672     Inst.addOperand(MCOperand::createReg(ARM::VPR));
5673     break;
5674   }
5675 
5676   if (Inst.getOpcode() != ARM::FMSTAT) {
5677     unsigned Rt = fieldFromInstruction(Val, 12, 4);
5678 
5679     if (featureBits[ARM::ModeThumb] && !featureBits[ARM::HasV8Ops]) {
5680       if (Rt == 13 || Rt == 15)
5681         S = MCDisassembler::SoftFail;
5682       Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
5683     } else
5684       Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder));
5685   }
5686 
5687   // Add explicit operand for the source sysreg, similarly to above.
5688   switch (Inst.getOpcode()) {
5689   case ARM::VMRS_FPSCR_NZCVQC:
5690     Inst.addOperand(MCOperand::createReg(ARM::FPSCR_NZCV));
5691     break;
5692   case ARM::VMRS_P0:
5693     Inst.addOperand(MCOperand::createReg(ARM::VPR));
5694     break;
5695   }
5696 
5697   if (featureBits[ARM::ModeThumb]) {
5698     Inst.addOperand(MCOperand::createImm(ARMCC::AL));
5699     Inst.addOperand(MCOperand::createReg(0));
5700   } else {
5701     unsigned pred = fieldFromInstruction(Val, 28, 4);
5702     if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5703       return MCDisassembler::Fail;
5704   }
5705 
5706   return S;
5707 }
5708 
5709 template <bool isSigned, bool isNeg, int size>
5710 static DecodeStatus DecodeBFLabelOperand(MCInst &Inst, unsigned Val,
5711                                          uint64_t Address,
5712                                          const void *Decoder) {
5713   DecodeStatus S = MCDisassembler::Success;
5714   if (Val == 0)
5715     S = MCDisassembler::SoftFail;
5716 
5717   uint64_t DecVal;
5718   if (isSigned)
5719     DecVal = SignExtend32<size + 1>(Val << 1);
5720   else
5721     DecVal = (Val << 1);
5722 
5723   if (!tryAddingSymbolicOperand(Address, Address + DecVal + 4, true, 4, Inst,
5724                                 Decoder))
5725     Inst.addOperand(MCOperand::createImm(isNeg ? -DecVal : DecVal));
5726   return S;
5727 }
5728 
5729 static DecodeStatus DecodeBFAfterTargetOperand(MCInst &Inst, unsigned Val,
5730                                                uint64_t Address,
5731                                                const void *Decoder) {
5732 
5733   uint64_t LocImm = Inst.getOperand(0).getImm();
5734   Val = LocImm + (2 << Val);
5735   if (!tryAddingSymbolicOperand(Address, Address + Val + 4, true, 4, Inst,
5736                                 Decoder))
5737     Inst.addOperand(MCOperand::createImm(Val));
5738   return MCDisassembler::Success;
5739 }
5740 
5741 static DecodeStatus DecodePredNoALOperand(MCInst &Inst, unsigned Val,
5742                                           uint64_t Address,
5743                                           const void *Decoder) {
5744   if (Val >= ARMCC::AL)  // also exclude the non-condition NV
5745     return MCDisassembler::Fail;
5746   Inst.addOperand(MCOperand::createImm(Val));
5747   return MCDisassembler::Success;
5748 }
5749 
5750 static DecodeStatus DecodeLOLoop(MCInst &Inst, unsigned Insn, uint64_t Address,
5751                                  const void *Decoder) {
5752   DecodeStatus S = MCDisassembler::Success;
5753 
5754   unsigned Imm = fieldFromInstruction(Insn, 11, 1) |
5755                  fieldFromInstruction(Insn, 1, 10) << 1;
5756   switch (Inst.getOpcode()) {
5757   case ARM::t2LEUpdate:
5758     Inst.addOperand(MCOperand::createReg(ARM::LR));
5759     Inst.addOperand(MCOperand::createReg(ARM::LR));
5760     LLVM_FALLTHROUGH;
5761   case ARM::t2LE:
5762     if (!Check(S, DecodeBFLabelOperand<false, true, 11>(Inst, Imm, Address,
5763                                                         Decoder)))
5764       return MCDisassembler::Fail;
5765     break;
5766   case ARM::t2WLS:
5767     Inst.addOperand(MCOperand::createReg(ARM::LR));
5768     if (!Check(S,
5769                DecoderGPRRegisterClass(Inst, fieldFromInstruction(Insn, 16, 4),
5770                                        Address, Decoder)) ||
5771         !Check(S, DecodeBFLabelOperand<false, false, 11>(Inst, Imm, Address,
5772                                                          Decoder)))
5773       return MCDisassembler::Fail;
5774     break;
5775   case ARM::t2DLS:
5776     unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5777     if (Rn == 0xF) {
5778       return MCDisassembler::Fail;
5779     } else {
5780       Inst.addOperand(MCOperand::createReg(ARM::LR));
5781       if (!Check(S, DecoderGPRRegisterClass(Inst,
5782                                             fieldFromInstruction(Insn, 16, 4),
5783                                             Address, Decoder)))
5784         return MCDisassembler::Fail;
5785     }
5786     break;
5787   }
5788   return S;
5789 }
5790 
5791 static DecodeStatus DecodeLongShiftOperand(MCInst &Inst, unsigned Val,
5792                                            uint64_t Address,
5793                                            const void *Decoder) {
5794   DecodeStatus S = MCDisassembler::Success;
5795 
5796   if (Val == 0)
5797     Val = 32;
5798 
5799   Inst.addOperand(MCOperand::createImm(Val));
5800 
5801   return S;
5802 }
5803 
5804 static DecodeStatus DecodetGPROddRegisterClass(MCInst &Inst, unsigned RegNo,
5805                                    uint64_t Address, const void *Decoder) {
5806   if ((RegNo) + 1 > 11)
5807     return MCDisassembler::Fail;
5808 
5809   unsigned Register = GPRDecoderTable[(RegNo) + 1];
5810   Inst.addOperand(MCOperand::createReg(Register));
5811   return MCDisassembler::Success;
5812 }
5813 
5814 static DecodeStatus DecodetGPREvenRegisterClass(MCInst &Inst, unsigned RegNo,
5815                                    uint64_t Address, const void *Decoder) {
5816   if ((RegNo) > 14)
5817     return MCDisassembler::Fail;
5818 
5819   unsigned Register = GPRDecoderTable[(RegNo)];
5820   Inst.addOperand(MCOperand::createReg(Register));
5821   return MCDisassembler::Success;
5822 }
5823 
5824 static DecodeStatus DecodeVSCCLRM(MCInst &Inst, unsigned Insn, uint64_t Address,
5825                                   const void *Decoder) {
5826   DecodeStatus S = MCDisassembler::Success;
5827 
5828   Inst.addOperand(MCOperand::createImm(ARMCC::AL));
5829   Inst.addOperand(MCOperand::createReg(0));
5830   if (Inst.getOpcode() == ARM::VSCCLRMD) {
5831     unsigned reglist = (fieldFromInstruction(Insn, 1, 7) << 1) |
5832                        (fieldFromInstruction(Insn, 12, 4) << 8) |
5833                        (fieldFromInstruction(Insn, 22, 1) << 12);
5834     if (!Check(S, DecodeDPRRegListOperand(Inst, reglist, Address, Decoder))) {
5835       return MCDisassembler::Fail;
5836     }
5837   } else {
5838     unsigned reglist = fieldFromInstruction(Insn, 0, 8) |
5839                        (fieldFromInstruction(Insn, 22, 1) << 8) |
5840                        (fieldFromInstruction(Insn, 12, 4) << 9);
5841     if (!Check(S, DecodeSPRRegListOperand(Inst, reglist, Address, Decoder))) {
5842       return MCDisassembler::Fail;
5843     }
5844   }
5845   Inst.addOperand(MCOperand::createReg(ARM::VPR));
5846 
5847   return S;
5848 }
5849 
5850 static DecodeStatus DecodeMQPRRegisterClass(MCInst &Inst, unsigned RegNo,
5851                               uint64_t Address,
5852                               const void *Decoder) {
5853   if (RegNo > 7)
5854     return MCDisassembler::Fail;
5855 
5856   unsigned Register = QPRDecoderTable[RegNo];
5857   Inst.addOperand(MCOperand::createReg(Register));
5858   return MCDisassembler::Success;
5859 }
5860 
5861 static DecodeStatus DecodeVPTMaskOperand(MCInst &Inst, unsigned Val,
5862                                          uint64_t Address,
5863                                          const void *Decoder) {
5864   DecodeStatus S = MCDisassembler::Success;
5865 
5866   // Parse VPT mask and encode it in the MCInst as an immediate with the same
5867   // format as the it_mask.  That is, from the second 'e|t' encode 'e' as 1 and
5868   // 't' as 0 and finish with a 1.
5869   unsigned Imm = 0;
5870   // We always start with a 't'.
5871   unsigned CurBit = 0;
5872   for (int i = 3; i >= 0; --i) {
5873     // If the bit we are looking at is not the same as last one, invert the
5874     // CurBit, if it is the same leave it as is.
5875     CurBit ^= (Val >> i) & 1U;
5876 
5877     // Encode the CurBit at the right place in the immediate.
5878     Imm |= (CurBit << i);
5879 
5880     // If we are done, finish the encoding with a 1.
5881     if ((Val & ~(~0U << i)) == 0) {
5882       Imm |= 1U << i;
5883       break;
5884     }
5885   }
5886 
5887   Inst.addOperand(MCOperand::createImm(Imm));
5888 
5889   return S;
5890 }
5891 
5892 static DecodeStatus DecodeVpredROperand(MCInst &Inst, unsigned RegNo,
5893                                         uint64_t Address, const void *Decoder) {
5894   // The vpred_r operand type includes an MQPR register field derived
5895   // from the encoding. But we don't actually want to add an operand
5896   // to the MCInst at this stage, because AddThumbPredicate will do it
5897   // later, and will infer the register number from the TIED_TO
5898   // constraint. So this is a deliberately empty decoder method that
5899   // will inhibit the auto-generated disassembly code from adding an
5900   // operand at all.
5901   return MCDisassembler::Success;
5902 }
5903 
5904 static DecodeStatus DecodeRestrictedIPredicateOperand(MCInst &Inst,
5905                                                       unsigned Val,
5906                                                       uint64_t Address,
5907                                                       const void *Decoder) {
5908   Inst.addOperand(MCOperand::createImm((Val & 0x1) == 0 ? ARMCC::EQ : ARMCC::NE));
5909   return MCDisassembler::Success;
5910 }
5911 
5912 static DecodeStatus DecodeRestrictedSPredicateOperand(MCInst &Inst,
5913                                                       unsigned Val,
5914                                                       uint64_t Address,
5915                                                       const void *Decoder) {
5916   unsigned Code;
5917   switch (Val & 0x3) {
5918   case 0:
5919     Code = ARMCC::GE;
5920     break;
5921   case 1:
5922     Code = ARMCC::LT;
5923     break;
5924   case 2:
5925     Code = ARMCC::GT;
5926     break;
5927   case 3:
5928     Code = ARMCC::LE;
5929     break;
5930   }
5931   Inst.addOperand(MCOperand::createImm(Code));
5932   return MCDisassembler::Success;
5933 }
5934 
5935 static DecodeStatus DecodeRestrictedUPredicateOperand(MCInst &Inst,
5936                                                       unsigned Val,
5937                                                       uint64_t Address,
5938                                                       const void *Decoder) {
5939   Inst.addOperand(MCOperand::createImm((Val & 0x1) == 0 ? ARMCC::HS : ARMCC::HI));
5940   return MCDisassembler::Success;
5941 }
5942 
5943 static DecodeStatus DecodeRestrictedFPPredicateOperand(MCInst &Inst, unsigned Val,
5944                                                      uint64_t Address,
5945                                                      const void *Decoder) {
5946   unsigned Code;
5947   switch (Val) {
5948   default:
5949     return MCDisassembler::Fail;
5950   case 0:
5951     Code = ARMCC::EQ;
5952     break;
5953   case 1:
5954     Code = ARMCC::NE;
5955     break;
5956   case 4:
5957     Code = ARMCC::GE;
5958     break;
5959   case 5:
5960     Code = ARMCC::LT;
5961     break;
5962   case 6:
5963     Code = ARMCC::GT;
5964     break;
5965   case 7:
5966     Code = ARMCC::LE;
5967     break;
5968   }
5969 
5970   Inst.addOperand(MCOperand::createImm(Code));
5971   return MCDisassembler::Success;
5972 }
5973 
5974 static unsigned FixedRegForVSTRVLDR_SYSREG(unsigned Opcode) {
5975   switch (Opcode) {
5976   case ARM::VSTR_P0_off:
5977   case ARM::VSTR_P0_pre:
5978   case ARM::VSTR_P0_post:
5979   case ARM::VLDR_P0_off:
5980   case ARM::VLDR_P0_pre:
5981   case ARM::VLDR_P0_post:
5982     return ARM::P0;
5983   default:
5984     return 0;
5985   }
5986 }
5987 
5988 template<bool Writeback>
5989 static DecodeStatus DecodeVSTRVLDR_SYSREG(MCInst &Inst, unsigned Val,
5990                                           uint64_t Address,
5991                                           const void *Decoder) {
5992   switch (Inst.getOpcode()) {
5993   case ARM::VSTR_FPSCR_pre:
5994   case ARM::VSTR_FPSCR_NZCVQC_pre:
5995   case ARM::VLDR_FPSCR_pre:
5996   case ARM::VLDR_FPSCR_NZCVQC_pre:
5997   case ARM::VSTR_FPSCR_off:
5998   case ARM::VSTR_FPSCR_NZCVQC_off:
5999   case ARM::VLDR_FPSCR_off:
6000   case ARM::VLDR_FPSCR_NZCVQC_off:
6001   case ARM::VSTR_FPSCR_post:
6002   case ARM::VSTR_FPSCR_NZCVQC_post:
6003   case ARM::VLDR_FPSCR_post:
6004   case ARM::VLDR_FPSCR_NZCVQC_post:
6005     const FeatureBitset &featureBits =
6006         ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
6007 
6008     if (!featureBits[ARM::HasMVEIntegerOps] && !featureBits[ARM::FeatureVFP2])
6009       return MCDisassembler::Fail;
6010   }
6011 
6012   DecodeStatus S = MCDisassembler::Success;
6013   if (unsigned Sysreg = FixedRegForVSTRVLDR_SYSREG(Inst.getOpcode()))
6014     Inst.addOperand(MCOperand::createReg(Sysreg));
6015   unsigned Rn = fieldFromInstruction(Val, 16, 4);
6016   unsigned addr = fieldFromInstruction(Val, 0, 7) |
6017                   (fieldFromInstruction(Val, 23, 1) << 7) | (Rn << 8);
6018 
6019   if (Writeback) {
6020     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
6021       return MCDisassembler::Fail;
6022   }
6023   if (!Check(S, DecodeT2AddrModeImm7s4(Inst, addr, Address, Decoder)))
6024     return MCDisassembler::Fail;
6025 
6026   Inst.addOperand(MCOperand::createImm(ARMCC::AL));
6027   Inst.addOperand(MCOperand::createReg(0));
6028 
6029   return S;
6030 }
6031 
6032 template <int shift>
6033 static DecodeStatus DecodeExpandedImmOperand(MCInst &Inst, unsigned Val,
6034                                              uint64_t Address,
6035                                              const void *Decoder) {
6036     Val <<= shift;
6037 
6038     Inst.addOperand(MCOperand::createImm(Val));
6039     return MCDisassembler::Success;
6040 }
6041 
6042 static DecodeStatus DecodeMVEOverlappingLongShift(
6043   MCInst &Inst, unsigned Insn, uint64_t Address, const void *Decoder) {
6044   DecodeStatus S = MCDisassembler::Success;
6045 
6046   unsigned RdaLo = fieldFromInstruction(Insn, 17, 3) << 1;
6047   unsigned RdaHi = fieldFromInstruction(Insn, 9, 3) << 1;
6048   unsigned Rm = fieldFromInstruction(Insn, 12, 4);
6049 
6050   if (RdaHi == 14) {
6051     // This value of RdaHi (really indicating pc, because RdaHi has to
6052     // be an odd-numbered register, so the low bit will be set by the
6053     // decode function below) indicates that we must decode as SQRSHR
6054     // or UQRSHL, which both have a single Rda register field with all
6055     // four bits.
6056     unsigned Rda = fieldFromInstruction(Insn, 16, 4);
6057 
6058     switch (Inst.getOpcode()) {
6059       case ARM::MVE_ASRLr:
6060       case ARM::MVE_SQRSHRL:
6061         Inst.setOpcode(ARM::MVE_SQRSHR);
6062         break;
6063       case ARM::MVE_LSLLr:
6064       case ARM::MVE_UQRSHLL:
6065         Inst.setOpcode(ARM::MVE_UQRSHL);
6066         break;
6067       default:
6068         llvm_unreachable("Unexpected starting opcode!");
6069     }
6070 
6071     // Rda as output parameter
6072     if (!Check(S, DecoderGPRRegisterClass(Inst, Rda, Address, Decoder)))
6073       return MCDisassembler::Fail;
6074 
6075     // Rda again as input parameter
6076     if (!Check(S, DecoderGPRRegisterClass(Inst, Rda, Address, Decoder)))
6077       return MCDisassembler::Fail;
6078 
6079     // Rm, the amount to shift by
6080     if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
6081       return MCDisassembler::Fail;
6082 
6083     return S;
6084   }
6085 
6086   // Otherwise, we decode as whichever opcode our caller has already
6087   // put into Inst. Those all look the same:
6088 
6089   // RdaLo,RdaHi as output parameters
6090   if (!Check(S, DecodetGPREvenRegisterClass(Inst, RdaLo, Address, Decoder)))
6091     return MCDisassembler::Fail;
6092   if (!Check(S, DecodetGPROddRegisterClass(Inst, RdaHi, Address, Decoder)))
6093     return MCDisassembler::Fail;
6094 
6095   // RdaLo,RdaHi again as input parameters
6096   if (!Check(S, DecodetGPREvenRegisterClass(Inst, RdaLo, Address, Decoder)))
6097     return MCDisassembler::Fail;
6098   if (!Check(S, DecodetGPROddRegisterClass(Inst, RdaHi, Address, Decoder)))
6099     return MCDisassembler::Fail;
6100 
6101   // Rm, the amount to shift by
6102   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
6103     return MCDisassembler::Fail;
6104 
6105   return S;
6106 }
6107