xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision ed4a602515291ceaf69237afff13cc94f83eb3e8)
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 static DecodeStatus DecodeMVEOverlappingLongShift(MCInst &Inst, unsigned Insn,
508                                                   uint64_t Address,
509                                                   const void *Decoder);
510 #include "ARMGenDisassemblerTables.inc"
511 
512 static MCDisassembler *createARMDisassembler(const Target &T,
513                                              const MCSubtargetInfo &STI,
514                                              MCContext &Ctx) {
515   return new ARMDisassembler(STI, Ctx);
516 }
517 
518 static MCDisassembler *createThumbDisassembler(const Target &T,
519                                                const MCSubtargetInfo &STI,
520                                                MCContext &Ctx) {
521   return new ThumbDisassembler(STI, Ctx);
522 }
523 
524 // Post-decoding checks
525 static DecodeStatus checkDecodedInstruction(MCInst &MI, uint64_t &Size,
526                                             uint64_t Address, raw_ostream &OS,
527                                             raw_ostream &CS,
528                                             uint32_t Insn,
529                                             DecodeStatus Result) {
530   switch (MI.getOpcode()) {
531     case ARM::HVC: {
532       // HVC is undefined if condition = 0xf otherwise upredictable
533       // if condition != 0xe
534       uint32_t Cond = (Insn >> 28) & 0xF;
535       if (Cond == 0xF)
536         return MCDisassembler::Fail;
537       if (Cond != 0xE)
538         return MCDisassembler::SoftFail;
539       return Result;
540     }
541     case ARM::t2ADDri:
542     case ARM::t2ADDri12:
543     case ARM::t2ADDrr:
544     case ARM::t2ADDrs:
545     case ARM::t2SUBri:
546     case ARM::t2SUBri12:
547     case ARM::t2SUBrr:
548     case ARM::t2SUBrs:
549       if (MI.getOperand(0).getReg() == ARM::SP &&
550           MI.getOperand(1).getReg() != ARM::SP)
551         return MCDisassembler::SoftFail;
552       return Result;
553     default: return Result;
554   }
555 }
556 
557 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
558                                              ArrayRef<uint8_t> Bytes,
559                                              uint64_t Address, raw_ostream &OS,
560                                              raw_ostream &CS) const {
561   CommentStream = &CS;
562 
563   assert(!STI.getFeatureBits()[ARM::ModeThumb] &&
564          "Asked to disassemble an ARM instruction but Subtarget is in Thumb "
565          "mode!");
566 
567   // We want to read exactly 4 bytes of data.
568   if (Bytes.size() < 4) {
569     Size = 0;
570     return MCDisassembler::Fail;
571   }
572 
573   // Encoded as a small-endian 32-bit word in the stream.
574   uint32_t Insn =
575       (Bytes[3] << 24) | (Bytes[2] << 16) | (Bytes[1] << 8) | (Bytes[0] << 0);
576 
577   // Calling the auto-generated decoder function.
578   DecodeStatus Result =
579       decodeInstruction(DecoderTableARM32, MI, Insn, Address, this, STI);
580   if (Result != MCDisassembler::Fail) {
581     Size = 4;
582     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
583   }
584 
585   struct DecodeTable {
586     const uint8_t *P;
587     bool DecodePred;
588   };
589 
590   const DecodeTable Tables[] = {
591       {DecoderTableVFP32, false},      {DecoderTableVFPV832, false},
592       {DecoderTableNEONData32, true},  {DecoderTableNEONLoadStore32, true},
593       {DecoderTableNEONDup32, true},   {DecoderTablev8NEON32, false},
594       {DecoderTablev8Crypto32, false},
595   };
596 
597   for (auto Table : Tables) {
598     Result = decodeInstruction(Table.P, MI, Insn, Address, this, STI);
599     if (Result != MCDisassembler::Fail) {
600       Size = 4;
601       // Add a fake predicate operand, because we share these instruction
602       // definitions with Thumb2 where these instructions are predicable.
603       if (Table.DecodePred && !DecodePredicateOperand(MI, 0xE, Address, this))
604         return MCDisassembler::Fail;
605       return Result;
606     }
607   }
608 
609   Result =
610       decodeInstruction(DecoderTableCoProc32, MI, Insn, Address, this, STI);
611   if (Result != MCDisassembler::Fail) {
612     Size = 4;
613     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
614   }
615 
616   Size = 4;
617   return MCDisassembler::Fail;
618 }
619 
620 namespace llvm {
621 
622 extern const MCInstrDesc ARMInsts[];
623 
624 } // end namespace llvm
625 
626 /// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the
627 /// immediate Value in the MCInst.  The immediate Value has had any PC
628 /// adjustment made by the caller.  If the instruction is a branch instruction
629 /// then isBranch is true, else false.  If the getOpInfo() function was set as
630 /// part of the setupForSymbolicDisassembly() call then that function is called
631 /// to get any symbolic information at the Address for this instruction.  If
632 /// that returns non-zero then the symbolic information it returns is used to
633 /// create an MCExpr and that is added as an operand to the MCInst.  If
634 /// getOpInfo() returns zero and isBranch is true then a symbol look up for
635 /// Value is done and if a symbol is found an MCExpr is created with that, else
636 /// an MCExpr with Value is created.  This function returns true if it adds an
637 /// operand to the MCInst and false otherwise.
638 static bool tryAddingSymbolicOperand(uint64_t Address, int32_t Value,
639                                      bool isBranch, uint64_t InstSize,
640                                      MCInst &MI, const void *Decoder) {
641   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
642   // FIXME: Does it make sense for value to be negative?
643   return Dis->tryAddingSymbolicOperand(MI, (uint32_t)Value, Address, isBranch,
644                                        /* Offset */ 0, InstSize);
645 }
646 
647 /// tryAddingPcLoadReferenceComment - trys to add a comment as to what is being
648 /// referenced by a load instruction with the base register that is the Pc.
649 /// These can often be values in a literal pool near the Address of the
650 /// instruction.  The Address of the instruction and its immediate Value are
651 /// used as a possible literal pool entry.  The SymbolLookUp call back will
652 /// return the name of a symbol referenced by the literal pool's entry if
653 /// the referenced address is that of a symbol.  Or it will return a pointer to
654 /// a literal 'C' string if the referenced address of the literal pool's entry
655 /// is an address into a section with 'C' string literals.
656 static void tryAddingPcLoadReferenceComment(uint64_t Address, int Value,
657                                             const void *Decoder) {
658   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
659   Dis->tryAddingPcLoadReferenceComment(Value, Address);
660 }
661 
662 // Thumb1 instructions don't have explicit S bits.  Rather, they
663 // implicitly set CPSR.  Since it's not represented in the encoding, the
664 // auto-generated decoder won't inject the CPSR operand.  We need to fix
665 // that as a post-pass.
666 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
667   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
668   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
669   MCInst::iterator I = MI.begin();
670   for (unsigned i = 0; i < NumOps; ++i, ++I) {
671     if (I == MI.end()) break;
672     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
673       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
674       MI.insert(I, MCOperand::createReg(InITBlock ? 0 : ARM::CPSR));
675       return;
676     }
677   }
678 
679   MI.insert(I, MCOperand::createReg(InITBlock ? 0 : ARM::CPSR));
680 }
681 
682 static bool isVectorPredicable(unsigned Opcode) {
683   const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
684   unsigned short NumOps = ARMInsts[Opcode].NumOperands;
685   for (unsigned i = 0; i < NumOps; ++i) {
686     if (ARM::isVpred(OpInfo[i].OperandType))
687       return true;
688   }
689   return false;
690 }
691 
692 // Most Thumb instructions don't have explicit predicates in the
693 // encoding, but rather get their predicates from IT context.  We need
694 // to fix up the predicate operands using this context information as a
695 // post-pass.
696 MCDisassembler::DecodeStatus
697 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
698   MCDisassembler::DecodeStatus S = Success;
699 
700   const FeatureBitset &FeatureBits = getSubtargetInfo().getFeatureBits();
701 
702   // A few instructions actually have predicates encoded in them.  Don't
703   // try to overwrite it if we're seeing one of those.
704   switch (MI.getOpcode()) {
705     case ARM::tBcc:
706     case ARM::t2Bcc:
707     case ARM::tCBZ:
708     case ARM::tCBNZ:
709     case ARM::tCPS:
710     case ARM::t2CPS3p:
711     case ARM::t2CPS2p:
712     case ARM::t2CPS1p:
713     case ARM::t2CSEL:
714     case ARM::t2CSINC:
715     case ARM::t2CSINV:
716     case ARM::t2CSNEG:
717     case ARM::tMOVSr:
718     case ARM::tSETEND:
719       // Some instructions (mostly conditional branches) are not
720       // allowed in IT blocks.
721       if (ITBlock.instrInITBlock())
722         S = SoftFail;
723       else
724         return Success;
725       break;
726     case ARM::t2HINT:
727       if (MI.getOperand(0).getImm() == 0x10 && (FeatureBits[ARM::FeatureRAS]) != 0)
728         S = SoftFail;
729       break;
730     case ARM::tB:
731     case ARM::t2B:
732     case ARM::t2TBB:
733     case ARM::t2TBH:
734       // Some instructions (mostly unconditional branches) can
735       // only appears at the end of, or outside of, an IT.
736       if (ITBlock.instrInITBlock() && !ITBlock.instrLastInITBlock())
737         S = SoftFail;
738       break;
739     default:
740       break;
741   }
742 
743   // Warn on non-VPT predicable instruction in a VPT block and a VPT
744   // predicable instruction in an IT block
745   if ((!isVectorPredicable(MI.getOpcode()) && VPTBlock.instrInVPTBlock()) ||
746        (isVectorPredicable(MI.getOpcode()) && ITBlock.instrInITBlock()))
747     S = SoftFail;
748 
749   // If we're in an IT/VPT block, base the predicate on that.  Otherwise,
750   // assume a predicate of AL.
751   unsigned CC = ARMCC::AL;
752   unsigned VCC = ARMVCC::None;
753   if (ITBlock.instrInITBlock()) {
754     CC = ITBlock.getITCC();
755     ITBlock.advanceITState();
756   } else if (VPTBlock.instrInVPTBlock()) {
757     VCC = VPTBlock.getVPTPred();
758     VPTBlock.advanceVPTState();
759   }
760 
761   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
762   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
763 
764   MCInst::iterator CCI = MI.begin();
765   for (unsigned i = 0; i < NumOps; ++i, ++CCI) {
766     if (OpInfo[i].isPredicate() || CCI == MI.end()) break;
767   }
768 
769   if (ARMInsts[MI.getOpcode()].isPredicable()) {
770     CCI = MI.insert(CCI, MCOperand::createImm(CC));
771     ++CCI;
772     if (CC == ARMCC::AL)
773       MI.insert(CCI, MCOperand::createReg(0));
774     else
775       MI.insert(CCI, MCOperand::createReg(ARM::CPSR));
776   } else if (CC != ARMCC::AL) {
777     Check(S, SoftFail);
778   }
779 
780   MCInst::iterator VCCI = MI.begin();
781   unsigned VCCPos;
782   for (VCCPos = 0; VCCPos < NumOps; ++VCCPos, ++VCCI) {
783     if (ARM::isVpred(OpInfo[VCCPos].OperandType) || VCCI == MI.end()) break;
784   }
785 
786   if (isVectorPredicable(MI.getOpcode())) {
787     VCCI = MI.insert(VCCI, MCOperand::createImm(VCC));
788     ++VCCI;
789     if (VCC == ARMVCC::None)
790       MI.insert(VCCI, MCOperand::createReg(0));
791     else
792       MI.insert(VCCI, MCOperand::createReg(ARM::P0));
793     if (OpInfo[VCCPos].OperandType == ARM::OPERAND_VPRED_R) {
794       int TiedOp = ARMInsts[MI.getOpcode()].getOperandConstraint(
795         VCCPos + 2, MCOI::TIED_TO);
796       assert(TiedOp >= 0 &&
797              "Inactive register in vpred_r is not tied to an output!");
798       MI.insert(VCCI, MI.getOperand(TiedOp));
799     }
800   } else if (VCC != ARMVCC::None) {
801     Check(S, SoftFail);
802   }
803 
804   return S;
805 }
806 
807 // Thumb VFP instructions are a special case.  Because we share their
808 // encodings between ARM and Thumb modes, and they are predicable in ARM
809 // mode, the auto-generated decoder will give them an (incorrect)
810 // predicate operand.  We need to rewrite these operands based on the IT
811 // context as a post-pass.
812 void ThumbDisassembler::UpdateThumbVFPPredicate(
813   DecodeStatus &S, MCInst &MI) const {
814   unsigned CC;
815   CC = ITBlock.getITCC();
816   if (CC == 0xF)
817     CC = ARMCC::AL;
818   if (ITBlock.instrInITBlock())
819     ITBlock.advanceITState();
820   else if (VPTBlock.instrInVPTBlock()) {
821     CC = VPTBlock.getVPTPred();
822     VPTBlock.advanceVPTState();
823   }
824 
825   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
826   MCInst::iterator I = MI.begin();
827   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
828   for (unsigned i = 0; i < NumOps; ++i, ++I) {
829     if (OpInfo[i].isPredicate() ) {
830       if (CC != ARMCC::AL && !ARMInsts[MI.getOpcode()].isPredicable())
831         Check(S, SoftFail);
832       I->setImm(CC);
833       ++I;
834       if (CC == ARMCC::AL)
835         I->setReg(0);
836       else
837         I->setReg(ARM::CPSR);
838       return;
839     }
840   }
841 }
842 
843 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
844                                                ArrayRef<uint8_t> Bytes,
845                                                uint64_t Address,
846                                                raw_ostream &OS,
847                                                raw_ostream &CS) const {
848   CommentStream = &CS;
849 
850   assert(STI.getFeatureBits()[ARM::ModeThumb] &&
851          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
852 
853   // We want to read exactly 2 bytes of data.
854   if (Bytes.size() < 2) {
855     Size = 0;
856     return MCDisassembler::Fail;
857   }
858 
859   uint16_t Insn16 = (Bytes[1] << 8) | Bytes[0];
860   DecodeStatus Result =
861       decodeInstruction(DecoderTableThumb16, MI, Insn16, Address, this, STI);
862   if (Result != MCDisassembler::Fail) {
863     Size = 2;
864     Check(Result, AddThumbPredicate(MI));
865     return Result;
866   }
867 
868   Result = decodeInstruction(DecoderTableThumbSBit16, MI, Insn16, Address, this,
869                              STI);
870   if (Result) {
871     Size = 2;
872     bool InITBlock = ITBlock.instrInITBlock();
873     Check(Result, AddThumbPredicate(MI));
874     AddThumb1SBit(MI, InITBlock);
875     return Result;
876   }
877 
878   Result =
879       decodeInstruction(DecoderTableThumb216, MI, Insn16, Address, this, STI);
880   if (Result != MCDisassembler::Fail) {
881     Size = 2;
882 
883     // Nested IT blocks are UNPREDICTABLE.  Must be checked before we add
884     // the Thumb predicate.
885     if (MI.getOpcode() == ARM::t2IT && ITBlock.instrInITBlock())
886       Result = MCDisassembler::SoftFail;
887 
888     Check(Result, AddThumbPredicate(MI));
889 
890     // If we find an IT instruction, we need to parse its condition
891     // code and mask operands so that we can apply them correctly
892     // to the subsequent instructions.
893     if (MI.getOpcode() == ARM::t2IT) {
894       unsigned Firstcond = MI.getOperand(0).getImm();
895       unsigned Mask = MI.getOperand(1).getImm();
896       ITBlock.setITState(Firstcond, Mask);
897 
898       // An IT instruction that would give a 'NV' predicate is unpredictable.
899       if (Firstcond == ARMCC::AL && !isPowerOf2_32(Mask))
900         CS << "unpredictable IT predicate sequence";
901     }
902 
903     return Result;
904   }
905 
906   // We want to read exactly 4 bytes of data.
907   if (Bytes.size() < 4) {
908     Size = 0;
909     return MCDisassembler::Fail;
910   }
911 
912   uint32_t Insn32 =
913       (Bytes[3] << 8) | (Bytes[2] << 0) | (Bytes[1] << 24) | (Bytes[0] << 16);
914 
915   Result =
916       decodeInstruction(DecoderTableMVE32, MI, Insn32, Address, this, STI);
917   if (Result != MCDisassembler::Fail) {
918     Size = 4;
919 
920     // Nested VPT blocks are UNPREDICTABLE. Must be checked before we add
921     // the VPT predicate.
922     if (isVPTOpcode(MI.getOpcode()) && VPTBlock.instrInVPTBlock())
923       Result = MCDisassembler::SoftFail;
924 
925     Check(Result, AddThumbPredicate(MI));
926 
927     if (isVPTOpcode(MI.getOpcode())) {
928       unsigned Mask = MI.getOperand(0).getImm();
929       VPTBlock.setVPTState(Mask);
930     }
931 
932     return Result;
933   }
934 
935   Result =
936       decodeInstruction(DecoderTableThumb32, MI, Insn32, Address, this, STI);
937   if (Result != MCDisassembler::Fail) {
938     Size = 4;
939     bool InITBlock = ITBlock.instrInITBlock();
940     Check(Result, AddThumbPredicate(MI));
941     AddThumb1SBit(MI, InITBlock);
942     return Result;
943   }
944 
945   Result =
946       decodeInstruction(DecoderTableThumb232, MI, Insn32, Address, this, STI);
947   if (Result != MCDisassembler::Fail) {
948     Size = 4;
949     Check(Result, AddThumbPredicate(MI));
950     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn32, Result);
951   }
952 
953   if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
954     Result =
955         decodeInstruction(DecoderTableVFP32, MI, Insn32, Address, this, STI);
956     if (Result != MCDisassembler::Fail) {
957       Size = 4;
958       UpdateThumbVFPPredicate(Result, MI);
959       return Result;
960     }
961   }
962 
963   Result =
964       decodeInstruction(DecoderTableVFPV832, MI, Insn32, Address, this, STI);
965   if (Result != MCDisassembler::Fail) {
966     Size = 4;
967     return Result;
968   }
969 
970   if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
971     Result = decodeInstruction(DecoderTableNEONDup32, MI, Insn32, Address, this,
972                                STI);
973     if (Result != MCDisassembler::Fail) {
974       Size = 4;
975       Check(Result, AddThumbPredicate(MI));
976       return Result;
977     }
978   }
979 
980   if (fieldFromInstruction(Insn32, 24, 8) == 0xF9) {
981     uint32_t NEONLdStInsn = Insn32;
982     NEONLdStInsn &= 0xF0FFFFFF;
983     NEONLdStInsn |= 0x04000000;
984     Result = decodeInstruction(DecoderTableNEONLoadStore32, MI, NEONLdStInsn,
985                                Address, this, STI);
986     if (Result != MCDisassembler::Fail) {
987       Size = 4;
988       Check(Result, AddThumbPredicate(MI));
989       return Result;
990     }
991   }
992 
993   if (fieldFromInstruction(Insn32, 24, 4) == 0xF) {
994     uint32_t NEONDataInsn = Insn32;
995     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
996     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
997     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
998     Result = decodeInstruction(DecoderTableNEONData32, MI, NEONDataInsn,
999                                Address, this, STI);
1000     if (Result != MCDisassembler::Fail) {
1001       Size = 4;
1002       Check(Result, AddThumbPredicate(MI));
1003       return Result;
1004     }
1005 
1006     uint32_t NEONCryptoInsn = Insn32;
1007     NEONCryptoInsn &= 0xF0FFFFFF; // Clear bits 27-24
1008     NEONCryptoInsn |= (NEONCryptoInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
1009     NEONCryptoInsn |= 0x12000000; // Set bits 28 and 25
1010     Result = decodeInstruction(DecoderTablev8Crypto32, MI, NEONCryptoInsn,
1011                                Address, this, STI);
1012     if (Result != MCDisassembler::Fail) {
1013       Size = 4;
1014       return Result;
1015     }
1016 
1017     uint32_t NEONv8Insn = Insn32;
1018     NEONv8Insn &= 0xF3FFFFFF; // Clear bits 27-26
1019     Result = decodeInstruction(DecoderTablev8NEON32, MI, NEONv8Insn, Address,
1020                                this, STI);
1021     if (Result != MCDisassembler::Fail) {
1022       Size = 4;
1023       return Result;
1024     }
1025   }
1026 
1027   Result =
1028       decodeInstruction(DecoderTableThumb2CoProc32, MI, Insn32, Address, this, STI);
1029   if (Result != MCDisassembler::Fail) {
1030     Size = 4;
1031     Check(Result, AddThumbPredicate(MI));
1032     return Result;
1033   }
1034 
1035   Size = 0;
1036   return MCDisassembler::Fail;
1037 }
1038 
1039 extern "C" void LLVMInitializeARMDisassembler() {
1040   TargetRegistry::RegisterMCDisassembler(getTheARMLETarget(),
1041                                          createARMDisassembler);
1042   TargetRegistry::RegisterMCDisassembler(getTheARMBETarget(),
1043                                          createARMDisassembler);
1044   TargetRegistry::RegisterMCDisassembler(getTheThumbLETarget(),
1045                                          createThumbDisassembler);
1046   TargetRegistry::RegisterMCDisassembler(getTheThumbBETarget(),
1047                                          createThumbDisassembler);
1048 }
1049 
1050 static const uint16_t GPRDecoderTable[] = {
1051   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
1052   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
1053   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
1054   ARM::R12, ARM::SP, ARM::LR, ARM::PC
1055 };
1056 
1057 static const uint16_t CLRMGPRDecoderTable[] = {
1058   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
1059   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
1060   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
1061   ARM::R12, 0, ARM::LR, ARM::APSR
1062 };
1063 
1064 static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
1065                                    uint64_t Address, const void *Decoder) {
1066   if (RegNo > 15)
1067     return MCDisassembler::Fail;
1068 
1069   unsigned Register = GPRDecoderTable[RegNo];
1070   Inst.addOperand(MCOperand::createReg(Register));
1071   return MCDisassembler::Success;
1072 }
1073 
1074 static DecodeStatus DecodeCLRMGPRRegisterClass(MCInst &Inst, unsigned RegNo,
1075                                                uint64_t Address,
1076                                                const void *Decoder) {
1077   if (RegNo > 15)
1078     return MCDisassembler::Fail;
1079 
1080   unsigned Register = CLRMGPRDecoderTable[RegNo];
1081   if (Register == 0)
1082     return MCDisassembler::Fail;
1083 
1084   Inst.addOperand(MCOperand::createReg(Register));
1085   return MCDisassembler::Success;
1086 }
1087 
1088 static DecodeStatus
1089 DecodeGPRnopcRegisterClass(MCInst &Inst, unsigned RegNo,
1090                            uint64_t Address, const void *Decoder) {
1091   DecodeStatus S = MCDisassembler::Success;
1092 
1093   if (RegNo == 15)
1094     S = MCDisassembler::SoftFail;
1095 
1096   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
1097 
1098   return S;
1099 }
1100 
1101 static DecodeStatus
1102 DecodeGPRwithAPSRRegisterClass(MCInst &Inst, unsigned RegNo,
1103                                uint64_t Address, const void *Decoder) {
1104   DecodeStatus S = MCDisassembler::Success;
1105 
1106   if (RegNo == 15)
1107   {
1108     Inst.addOperand(MCOperand::createReg(ARM::APSR_NZCV));
1109     return MCDisassembler::Success;
1110   }
1111 
1112   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
1113   return S;
1114 }
1115 
1116 static DecodeStatus
1117 DecodeGPRwithZRRegisterClass(MCInst &Inst, unsigned RegNo,
1118                              uint64_t Address, const void *Decoder) {
1119   DecodeStatus S = MCDisassembler::Success;
1120 
1121   if (RegNo == 15)
1122   {
1123     Inst.addOperand(MCOperand::createReg(ARM::ZR));
1124     return MCDisassembler::Success;
1125   }
1126 
1127   if (RegNo == 13)
1128     S = MCDisassembler::SoftFail;
1129 
1130   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
1131   return S;
1132 }
1133 
1134 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
1135                                    uint64_t Address, const void *Decoder) {
1136   if (RegNo > 7)
1137     return MCDisassembler::Fail;
1138   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
1139 }
1140 
1141 static const uint16_t GPRPairDecoderTable[] = {
1142   ARM::R0_R1, ARM::R2_R3,   ARM::R4_R5,  ARM::R6_R7,
1143   ARM::R8_R9, ARM::R10_R11, ARM::R12_SP
1144 };
1145 
1146 static DecodeStatus DecodeGPRPairRegisterClass(MCInst &Inst, unsigned RegNo,
1147                                    uint64_t Address, const void *Decoder) {
1148   DecodeStatus S = MCDisassembler::Success;
1149 
1150   if (RegNo > 13)
1151     return MCDisassembler::Fail;
1152 
1153   if ((RegNo & 1) || RegNo == 0xe)
1154      S = MCDisassembler::SoftFail;
1155 
1156   unsigned RegisterPair = GPRPairDecoderTable[RegNo/2];
1157   Inst.addOperand(MCOperand::createReg(RegisterPair));
1158   return S;
1159 }
1160 
1161 static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
1162                                    uint64_t Address, const void *Decoder) {
1163   unsigned Register = 0;
1164   switch (RegNo) {
1165     case 0:
1166       Register = ARM::R0;
1167       break;
1168     case 1:
1169       Register = ARM::R1;
1170       break;
1171     case 2:
1172       Register = ARM::R2;
1173       break;
1174     case 3:
1175       Register = ARM::R3;
1176       break;
1177     case 9:
1178       Register = ARM::R9;
1179       break;
1180     case 12:
1181       Register = ARM::R12;
1182       break;
1183     default:
1184       return MCDisassembler::Fail;
1185     }
1186 
1187   Inst.addOperand(MCOperand::createReg(Register));
1188   return MCDisassembler::Success;
1189 }
1190 
1191 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
1192                                    uint64_t Address, const void *Decoder) {
1193   DecodeStatus S = MCDisassembler::Success;
1194 
1195   const FeatureBitset &featureBits =
1196     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
1197 
1198   if ((RegNo == 13 && !featureBits[ARM::HasV8Ops]) || RegNo == 15)
1199     S = MCDisassembler::SoftFail;
1200 
1201   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
1202   return S;
1203 }
1204 
1205 static const uint16_t SPRDecoderTable[] = {
1206      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
1207      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
1208      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
1209     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
1210     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
1211     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
1212     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
1213     ARM::S28, ARM::S29, ARM::S30, ARM::S31
1214 };
1215 
1216 static DecodeStatus DecodeSPRRegisterClass(MCInst &Inst, unsigned RegNo,
1217                                    uint64_t Address, const void *Decoder) {
1218   if (RegNo > 31)
1219     return MCDisassembler::Fail;
1220 
1221   unsigned Register = SPRDecoderTable[RegNo];
1222   Inst.addOperand(MCOperand::createReg(Register));
1223   return MCDisassembler::Success;
1224 }
1225 
1226 static DecodeStatus DecodeHPRRegisterClass(MCInst &Inst, unsigned RegNo,
1227                                    uint64_t Address, const void *Decoder) {
1228   return DecodeSPRRegisterClass(Inst, RegNo, Address, Decoder);
1229 }
1230 
1231 static const uint16_t DPRDecoderTable[] = {
1232      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
1233      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
1234      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
1235     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
1236     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
1237     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
1238     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
1239     ARM::D28, ARM::D29, ARM::D30, ARM::D31
1240 };
1241 
1242 static DecodeStatus DecodeDPRRegisterClass(MCInst &Inst, unsigned RegNo,
1243                                    uint64_t Address, const void *Decoder) {
1244   const FeatureBitset &featureBits =
1245     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
1246 
1247   bool hasD32 = featureBits[ARM::FeatureD32];
1248 
1249   if (RegNo > 31 || (!hasD32 && RegNo > 15))
1250     return MCDisassembler::Fail;
1251 
1252   unsigned Register = DPRDecoderTable[RegNo];
1253   Inst.addOperand(MCOperand::createReg(Register));
1254   return MCDisassembler::Success;
1255 }
1256 
1257 static DecodeStatus DecodeDPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
1258                                    uint64_t Address, const void *Decoder) {
1259   if (RegNo > 7)
1260     return MCDisassembler::Fail;
1261   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
1262 }
1263 
1264 static DecodeStatus DecodeSPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
1265                                    uint64_t Address, const void *Decoder) {
1266   if (RegNo > 15)
1267     return MCDisassembler::Fail;
1268   return DecodeSPRRegisterClass(Inst, RegNo, Address, Decoder);
1269 }
1270 
1271 static DecodeStatus
1272 DecodeDPR_VFP2RegisterClass(MCInst &Inst, unsigned RegNo,
1273                             uint64_t Address, const void *Decoder) {
1274   if (RegNo > 15)
1275     return MCDisassembler::Fail;
1276   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
1277 }
1278 
1279 static const uint16_t QPRDecoderTable[] = {
1280      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
1281      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
1282      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
1283     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
1284 };
1285 
1286 static DecodeStatus DecodeQPRRegisterClass(MCInst &Inst, unsigned RegNo,
1287                                    uint64_t Address, const void *Decoder) {
1288   if (RegNo > 31 || (RegNo & 1) != 0)
1289     return MCDisassembler::Fail;
1290   RegNo >>= 1;
1291 
1292   unsigned Register = QPRDecoderTable[RegNo];
1293   Inst.addOperand(MCOperand::createReg(Register));
1294   return MCDisassembler::Success;
1295 }
1296 
1297 static const uint16_t DPairDecoderTable[] = {
1298   ARM::Q0,  ARM::D1_D2,   ARM::Q1,  ARM::D3_D4,   ARM::Q2,  ARM::D5_D6,
1299   ARM::Q3,  ARM::D7_D8,   ARM::Q4,  ARM::D9_D10,  ARM::Q5,  ARM::D11_D12,
1300   ARM::Q6,  ARM::D13_D14, ARM::Q7,  ARM::D15_D16, ARM::Q8,  ARM::D17_D18,
1301   ARM::Q9,  ARM::D19_D20, ARM::Q10, ARM::D21_D22, ARM::Q11, ARM::D23_D24,
1302   ARM::Q12, ARM::D25_D26, ARM::Q13, ARM::D27_D28, ARM::Q14, ARM::D29_D30,
1303   ARM::Q15
1304 };
1305 
1306 static DecodeStatus DecodeDPairRegisterClass(MCInst &Inst, unsigned RegNo,
1307                                    uint64_t Address, const void *Decoder) {
1308   if (RegNo > 30)
1309     return MCDisassembler::Fail;
1310 
1311   unsigned Register = DPairDecoderTable[RegNo];
1312   Inst.addOperand(MCOperand::createReg(Register));
1313   return MCDisassembler::Success;
1314 }
1315 
1316 static const uint16_t DPairSpacedDecoderTable[] = {
1317   ARM::D0_D2,   ARM::D1_D3,   ARM::D2_D4,   ARM::D3_D5,
1318   ARM::D4_D6,   ARM::D5_D7,   ARM::D6_D8,   ARM::D7_D9,
1319   ARM::D8_D10,  ARM::D9_D11,  ARM::D10_D12, ARM::D11_D13,
1320   ARM::D12_D14, ARM::D13_D15, ARM::D14_D16, ARM::D15_D17,
1321   ARM::D16_D18, ARM::D17_D19, ARM::D18_D20, ARM::D19_D21,
1322   ARM::D20_D22, ARM::D21_D23, ARM::D22_D24, ARM::D23_D25,
1323   ARM::D24_D26, ARM::D25_D27, ARM::D26_D28, ARM::D27_D29,
1324   ARM::D28_D30, ARM::D29_D31
1325 };
1326 
1327 static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst &Inst,
1328                                                    unsigned RegNo,
1329                                                    uint64_t Address,
1330                                                    const void *Decoder) {
1331   if (RegNo > 29)
1332     return MCDisassembler::Fail;
1333 
1334   unsigned Register = DPairSpacedDecoderTable[RegNo];
1335   Inst.addOperand(MCOperand::createReg(Register));
1336   return MCDisassembler::Success;
1337 }
1338 
1339 static DecodeStatus DecodePredicateOperand(MCInst &Inst, unsigned Val,
1340                                uint64_t Address, const void *Decoder) {
1341   DecodeStatus S = MCDisassembler::Success;
1342   if (Val == 0xF) return MCDisassembler::Fail;
1343   // AL predicate is not allowed on Thumb1 branches.
1344   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
1345     return MCDisassembler::Fail;
1346   if (Val != ARMCC::AL && !ARMInsts[Inst.getOpcode()].isPredicable())
1347     Check(S, MCDisassembler::SoftFail);
1348   Inst.addOperand(MCOperand::createImm(Val));
1349   if (Val == ARMCC::AL) {
1350     Inst.addOperand(MCOperand::createReg(0));
1351   } else
1352     Inst.addOperand(MCOperand::createReg(ARM::CPSR));
1353   return S;
1354 }
1355 
1356 static DecodeStatus DecodeCCOutOperand(MCInst &Inst, unsigned Val,
1357                                uint64_t Address, const void *Decoder) {
1358   if (Val)
1359     Inst.addOperand(MCOperand::createReg(ARM::CPSR));
1360   else
1361     Inst.addOperand(MCOperand::createReg(0));
1362   return MCDisassembler::Success;
1363 }
1364 
1365 static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Val,
1366                                uint64_t Address, const void *Decoder) {
1367   DecodeStatus S = MCDisassembler::Success;
1368 
1369   unsigned Rm = fieldFromInstruction(Val, 0, 4);
1370   unsigned type = fieldFromInstruction(Val, 5, 2);
1371   unsigned imm = fieldFromInstruction(Val, 7, 5);
1372 
1373   // Register-immediate
1374   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
1375     return MCDisassembler::Fail;
1376 
1377   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1378   switch (type) {
1379     case 0:
1380       Shift = ARM_AM::lsl;
1381       break;
1382     case 1:
1383       Shift = ARM_AM::lsr;
1384       break;
1385     case 2:
1386       Shift = ARM_AM::asr;
1387       break;
1388     case 3:
1389       Shift = ARM_AM::ror;
1390       break;
1391   }
1392 
1393   if (Shift == ARM_AM::ror && imm == 0)
1394     Shift = ARM_AM::rrx;
1395 
1396   unsigned Op = Shift | (imm << 3);
1397   Inst.addOperand(MCOperand::createImm(Op));
1398 
1399   return S;
1400 }
1401 
1402 static DecodeStatus DecodeSORegRegOperand(MCInst &Inst, unsigned Val,
1403                                uint64_t Address, const void *Decoder) {
1404   DecodeStatus S = MCDisassembler::Success;
1405 
1406   unsigned Rm = fieldFromInstruction(Val, 0, 4);
1407   unsigned type = fieldFromInstruction(Val, 5, 2);
1408   unsigned Rs = fieldFromInstruction(Val, 8, 4);
1409 
1410   // Register-register
1411   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1412     return MCDisassembler::Fail;
1413   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
1414     return MCDisassembler::Fail;
1415 
1416   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1417   switch (type) {
1418     case 0:
1419       Shift = ARM_AM::lsl;
1420       break;
1421     case 1:
1422       Shift = ARM_AM::lsr;
1423       break;
1424     case 2:
1425       Shift = ARM_AM::asr;
1426       break;
1427     case 3:
1428       Shift = ARM_AM::ror;
1429       break;
1430   }
1431 
1432   Inst.addOperand(MCOperand::createImm(Shift));
1433 
1434   return S;
1435 }
1436 
1437 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
1438                                  uint64_t Address, const void *Decoder) {
1439   DecodeStatus S = MCDisassembler::Success;
1440 
1441   bool NeedDisjointWriteback = false;
1442   unsigned WritebackReg = 0;
1443   bool CLRM = false;
1444   switch (Inst.getOpcode()) {
1445   default:
1446     break;
1447   case ARM::LDMIA_UPD:
1448   case ARM::LDMDB_UPD:
1449   case ARM::LDMIB_UPD:
1450   case ARM::LDMDA_UPD:
1451   case ARM::t2LDMIA_UPD:
1452   case ARM::t2LDMDB_UPD:
1453   case ARM::t2STMIA_UPD:
1454   case ARM::t2STMDB_UPD:
1455     NeedDisjointWriteback = true;
1456     WritebackReg = Inst.getOperand(0).getReg();
1457     break;
1458   case ARM::t2CLRM:
1459     CLRM = true;
1460     break;
1461   }
1462 
1463   // Empty register lists are not allowed.
1464   if (Val == 0) return MCDisassembler::Fail;
1465   for (unsigned i = 0; i < 16; ++i) {
1466     if (Val & (1 << i)) {
1467       if (CLRM) {
1468         if (!Check(S, DecodeCLRMGPRRegisterClass(Inst, i, Address, Decoder))) {
1469           return MCDisassembler::Fail;
1470         }
1471       } else {
1472         if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
1473           return MCDisassembler::Fail;
1474         // Writeback not allowed if Rn is in the target list.
1475         if (NeedDisjointWriteback && WritebackReg == Inst.end()[-1].getReg())
1476           Check(S, MCDisassembler::SoftFail);
1477       }
1478     }
1479   }
1480 
1481   return S;
1482 }
1483 
1484 static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
1485                                  uint64_t Address, const void *Decoder) {
1486   DecodeStatus S = MCDisassembler::Success;
1487 
1488   unsigned Vd = fieldFromInstruction(Val, 8, 5);
1489   unsigned regs = fieldFromInstruction(Val, 0, 8);
1490 
1491   // In case of unpredictable encoding, tweak the operands.
1492   if (regs == 0 || (Vd + regs) > 32) {
1493     regs = Vd + regs > 32 ? 32 - Vd : regs;
1494     regs = std::max( 1u, regs);
1495     S = MCDisassembler::SoftFail;
1496   }
1497 
1498   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
1499     return MCDisassembler::Fail;
1500   for (unsigned i = 0; i < (regs - 1); ++i) {
1501     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1502       return MCDisassembler::Fail;
1503   }
1504 
1505   return S;
1506 }
1507 
1508 static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
1509                                  uint64_t Address, const void *Decoder) {
1510   DecodeStatus S = MCDisassembler::Success;
1511 
1512   unsigned Vd = fieldFromInstruction(Val, 8, 5);
1513   unsigned regs = fieldFromInstruction(Val, 1, 7);
1514 
1515   // In case of unpredictable encoding, tweak the operands.
1516   if (regs == 0 || regs > 16 || (Vd + regs) > 32) {
1517     regs = Vd + regs > 32 ? 32 - Vd : regs;
1518     regs = std::max( 1u, regs);
1519     regs = std::min(16u, regs);
1520     S = MCDisassembler::SoftFail;
1521   }
1522 
1523   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
1524       return MCDisassembler::Fail;
1525   for (unsigned i = 0; i < (regs - 1); ++i) {
1526     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1527       return MCDisassembler::Fail;
1528   }
1529 
1530   return S;
1531 }
1532 
1533 static DecodeStatus DecodeBitfieldMaskOperand(MCInst &Inst, unsigned Val,
1534                                       uint64_t Address, const void *Decoder) {
1535   // This operand encodes a mask of contiguous zeros between a specified MSB
1536   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
1537   // the mask of all bits LSB-and-lower, and then xor them to create
1538   // the mask of that's all ones on [msb, lsb].  Finally we not it to
1539   // create the final mask.
1540   unsigned msb = fieldFromInstruction(Val, 5, 5);
1541   unsigned lsb = fieldFromInstruction(Val, 0, 5);
1542 
1543   DecodeStatus S = MCDisassembler::Success;
1544   if (lsb > msb) {
1545     Check(S, MCDisassembler::SoftFail);
1546     // The check above will cause the warning for the "potentially undefined
1547     // instruction encoding" but we can't build a bad MCOperand value here
1548     // with a lsb > msb or else printing the MCInst will cause a crash.
1549     lsb = msb;
1550   }
1551 
1552   uint32_t msb_mask = 0xFFFFFFFF;
1553   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;
1554   uint32_t lsb_mask = (1U << lsb) - 1;
1555 
1556   Inst.addOperand(MCOperand::createImm(~(msb_mask ^ lsb_mask)));
1557   return S;
1558 }
1559 
1560 static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
1561                                   uint64_t Address, const void *Decoder) {
1562   DecodeStatus S = MCDisassembler::Success;
1563 
1564   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1565   unsigned CRd = fieldFromInstruction(Insn, 12, 4);
1566   unsigned coproc = fieldFromInstruction(Insn, 8, 4);
1567   unsigned imm = fieldFromInstruction(Insn, 0, 8);
1568   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1569   unsigned U = fieldFromInstruction(Insn, 23, 1);
1570   const FeatureBitset &featureBits =
1571     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
1572 
1573   switch (Inst.getOpcode()) {
1574     case ARM::LDC_OFFSET:
1575     case ARM::LDC_PRE:
1576     case ARM::LDC_POST:
1577     case ARM::LDC_OPTION:
1578     case ARM::LDCL_OFFSET:
1579     case ARM::LDCL_PRE:
1580     case ARM::LDCL_POST:
1581     case ARM::LDCL_OPTION:
1582     case ARM::STC_OFFSET:
1583     case ARM::STC_PRE:
1584     case ARM::STC_POST:
1585     case ARM::STC_OPTION:
1586     case ARM::STCL_OFFSET:
1587     case ARM::STCL_PRE:
1588     case ARM::STCL_POST:
1589     case ARM::STCL_OPTION:
1590     case ARM::t2LDC_OFFSET:
1591     case ARM::t2LDC_PRE:
1592     case ARM::t2LDC_POST:
1593     case ARM::t2LDC_OPTION:
1594     case ARM::t2LDCL_OFFSET:
1595     case ARM::t2LDCL_PRE:
1596     case ARM::t2LDCL_POST:
1597     case ARM::t2LDCL_OPTION:
1598     case ARM::t2STC_OFFSET:
1599     case ARM::t2STC_PRE:
1600     case ARM::t2STC_POST:
1601     case ARM::t2STC_OPTION:
1602     case ARM::t2STCL_OFFSET:
1603     case ARM::t2STCL_PRE:
1604     case ARM::t2STCL_POST:
1605     case ARM::t2STCL_OPTION:
1606     case ARM::t2LDC2_OFFSET:
1607     case ARM::t2LDC2L_OFFSET:
1608     case ARM::t2LDC2_PRE:
1609     case ARM::t2LDC2L_PRE:
1610     case ARM::t2STC2_OFFSET:
1611     case ARM::t2STC2L_OFFSET:
1612     case ARM::t2STC2_PRE:
1613     case ARM::t2STC2L_PRE:
1614     case ARM::LDC2_OFFSET:
1615     case ARM::LDC2L_OFFSET:
1616     case ARM::LDC2_PRE:
1617     case ARM::LDC2L_PRE:
1618     case ARM::STC2_OFFSET:
1619     case ARM::STC2L_OFFSET:
1620     case ARM::STC2_PRE:
1621     case ARM::STC2L_PRE:
1622     case ARM::t2LDC2_OPTION:
1623     case ARM::t2STC2_OPTION:
1624     case ARM::t2LDC2_POST:
1625     case ARM::t2LDC2L_POST:
1626     case ARM::t2STC2_POST:
1627     case ARM::t2STC2L_POST:
1628     case ARM::LDC2_POST:
1629     case ARM::LDC2L_POST:
1630     case ARM::STC2_POST:
1631     case ARM::STC2L_POST:
1632       if (coproc == 0xA || coproc == 0xB ||
1633           (featureBits[ARM::HasV8_1MMainlineOps] &&
1634            (coproc == 0x8 || coproc == 0x9 || coproc == 0xA || coproc == 0xB ||
1635             coproc == 0xE || coproc == 0xF)))
1636         return MCDisassembler::Fail;
1637       break;
1638     default:
1639       break;
1640   }
1641 
1642   if (featureBits[ARM::HasV8Ops] && (coproc != 14))
1643     return MCDisassembler::Fail;
1644 
1645   Inst.addOperand(MCOperand::createImm(coproc));
1646   Inst.addOperand(MCOperand::createImm(CRd));
1647   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1648     return MCDisassembler::Fail;
1649 
1650   switch (Inst.getOpcode()) {
1651     case ARM::t2LDC2_OFFSET:
1652     case ARM::t2LDC2L_OFFSET:
1653     case ARM::t2LDC2_PRE:
1654     case ARM::t2LDC2L_PRE:
1655     case ARM::t2STC2_OFFSET:
1656     case ARM::t2STC2L_OFFSET:
1657     case ARM::t2STC2_PRE:
1658     case ARM::t2STC2L_PRE:
1659     case ARM::LDC2_OFFSET:
1660     case ARM::LDC2L_OFFSET:
1661     case ARM::LDC2_PRE:
1662     case ARM::LDC2L_PRE:
1663     case ARM::STC2_OFFSET:
1664     case ARM::STC2L_OFFSET:
1665     case ARM::STC2_PRE:
1666     case ARM::STC2L_PRE:
1667     case ARM::t2LDC_OFFSET:
1668     case ARM::t2LDCL_OFFSET:
1669     case ARM::t2LDC_PRE:
1670     case ARM::t2LDCL_PRE:
1671     case ARM::t2STC_OFFSET:
1672     case ARM::t2STCL_OFFSET:
1673     case ARM::t2STC_PRE:
1674     case ARM::t2STCL_PRE:
1675     case ARM::LDC_OFFSET:
1676     case ARM::LDCL_OFFSET:
1677     case ARM::LDC_PRE:
1678     case ARM::LDCL_PRE:
1679     case ARM::STC_OFFSET:
1680     case ARM::STCL_OFFSET:
1681     case ARM::STC_PRE:
1682     case ARM::STCL_PRE:
1683       imm = ARM_AM::getAM5Opc(U ? ARM_AM::add : ARM_AM::sub, imm);
1684       Inst.addOperand(MCOperand::createImm(imm));
1685       break;
1686     case ARM::t2LDC2_POST:
1687     case ARM::t2LDC2L_POST:
1688     case ARM::t2STC2_POST:
1689     case ARM::t2STC2L_POST:
1690     case ARM::LDC2_POST:
1691     case ARM::LDC2L_POST:
1692     case ARM::STC2_POST:
1693     case ARM::STC2L_POST:
1694     case ARM::t2LDC_POST:
1695     case ARM::t2LDCL_POST:
1696     case ARM::t2STC_POST:
1697     case ARM::t2STCL_POST:
1698     case ARM::LDC_POST:
1699     case ARM::LDCL_POST:
1700     case ARM::STC_POST:
1701     case ARM::STCL_POST:
1702       imm |= U << 8;
1703       LLVM_FALLTHROUGH;
1704     default:
1705       // The 'option' variant doesn't encode 'U' in the immediate since
1706       // the immediate is unsigned [0,255].
1707       Inst.addOperand(MCOperand::createImm(imm));
1708       break;
1709   }
1710 
1711   switch (Inst.getOpcode()) {
1712     case ARM::LDC_OFFSET:
1713     case ARM::LDC_PRE:
1714     case ARM::LDC_POST:
1715     case ARM::LDC_OPTION:
1716     case ARM::LDCL_OFFSET:
1717     case ARM::LDCL_PRE:
1718     case ARM::LDCL_POST:
1719     case ARM::LDCL_OPTION:
1720     case ARM::STC_OFFSET:
1721     case ARM::STC_PRE:
1722     case ARM::STC_POST:
1723     case ARM::STC_OPTION:
1724     case ARM::STCL_OFFSET:
1725     case ARM::STCL_PRE:
1726     case ARM::STCL_POST:
1727     case ARM::STCL_OPTION:
1728       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1729         return MCDisassembler::Fail;
1730       break;
1731     default:
1732       break;
1733   }
1734 
1735   return S;
1736 }
1737 
1738 static DecodeStatus
1739 DecodeAddrMode2IdxInstruction(MCInst &Inst, unsigned Insn,
1740                               uint64_t Address, const void *Decoder) {
1741   DecodeStatus S = MCDisassembler::Success;
1742 
1743   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1744   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
1745   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1746   unsigned imm = fieldFromInstruction(Insn, 0, 12);
1747   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1748   unsigned reg = fieldFromInstruction(Insn, 25, 1);
1749   unsigned P = fieldFromInstruction(Insn, 24, 1);
1750   unsigned W = fieldFromInstruction(Insn, 21, 1);
1751 
1752   // On stores, the writeback operand precedes Rt.
1753   switch (Inst.getOpcode()) {
1754     case ARM::STR_POST_IMM:
1755     case ARM::STR_POST_REG:
1756     case ARM::STRB_POST_IMM:
1757     case ARM::STRB_POST_REG:
1758     case ARM::STRT_POST_REG:
1759     case ARM::STRT_POST_IMM:
1760     case ARM::STRBT_POST_REG:
1761     case ARM::STRBT_POST_IMM:
1762       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1763         return MCDisassembler::Fail;
1764       break;
1765     default:
1766       break;
1767   }
1768 
1769   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1770     return MCDisassembler::Fail;
1771 
1772   // On loads, the writeback operand comes after Rt.
1773   switch (Inst.getOpcode()) {
1774     case ARM::LDR_POST_IMM:
1775     case ARM::LDR_POST_REG:
1776     case ARM::LDRB_POST_IMM:
1777     case ARM::LDRB_POST_REG:
1778     case ARM::LDRBT_POST_REG:
1779     case ARM::LDRBT_POST_IMM:
1780     case ARM::LDRT_POST_REG:
1781     case ARM::LDRT_POST_IMM:
1782       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1783         return MCDisassembler::Fail;
1784       break;
1785     default:
1786       break;
1787   }
1788 
1789   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1790     return MCDisassembler::Fail;
1791 
1792   ARM_AM::AddrOpc Op = ARM_AM::add;
1793   if (!fieldFromInstruction(Insn, 23, 1))
1794     Op = ARM_AM::sub;
1795 
1796   bool writeback = (P == 0) || (W == 1);
1797   unsigned idx_mode = 0;
1798   if (P && writeback)
1799     idx_mode = ARMII::IndexModePre;
1800   else if (!P && writeback)
1801     idx_mode = ARMII::IndexModePost;
1802 
1803   if (writeback && (Rn == 15 || Rn == Rt))
1804     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1805 
1806   if (reg) {
1807     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1808       return MCDisassembler::Fail;
1809     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1810     switch( fieldFromInstruction(Insn, 5, 2)) {
1811       case 0:
1812         Opc = ARM_AM::lsl;
1813         break;
1814       case 1:
1815         Opc = ARM_AM::lsr;
1816         break;
1817       case 2:
1818         Opc = ARM_AM::asr;
1819         break;
1820       case 3:
1821         Opc = ARM_AM::ror;
1822         break;
1823       default:
1824         return MCDisassembler::Fail;
1825     }
1826     unsigned amt = fieldFromInstruction(Insn, 7, 5);
1827     if (Opc == ARM_AM::ror && amt == 0)
1828       Opc = ARM_AM::rrx;
1829     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1830 
1831     Inst.addOperand(MCOperand::createImm(imm));
1832   } else {
1833     Inst.addOperand(MCOperand::createReg(0));
1834     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1835     Inst.addOperand(MCOperand::createImm(tmp));
1836   }
1837 
1838   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1839     return MCDisassembler::Fail;
1840 
1841   return S;
1842 }
1843 
1844 static DecodeStatus DecodeSORegMemOperand(MCInst &Inst, unsigned Val,
1845                                   uint64_t Address, const void *Decoder) {
1846   DecodeStatus S = MCDisassembler::Success;
1847 
1848   unsigned Rn = fieldFromInstruction(Val, 13, 4);
1849   unsigned Rm = fieldFromInstruction(Val,  0, 4);
1850   unsigned type = fieldFromInstruction(Val, 5, 2);
1851   unsigned imm = fieldFromInstruction(Val, 7, 5);
1852   unsigned U = fieldFromInstruction(Val, 12, 1);
1853 
1854   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1855   switch (type) {
1856     case 0:
1857       ShOp = ARM_AM::lsl;
1858       break;
1859     case 1:
1860       ShOp = ARM_AM::lsr;
1861       break;
1862     case 2:
1863       ShOp = ARM_AM::asr;
1864       break;
1865     case 3:
1866       ShOp = ARM_AM::ror;
1867       break;
1868   }
1869 
1870   if (ShOp == ARM_AM::ror && imm == 0)
1871     ShOp = ARM_AM::rrx;
1872 
1873   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1874     return MCDisassembler::Fail;
1875   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1876     return MCDisassembler::Fail;
1877   unsigned shift;
1878   if (U)
1879     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1880   else
1881     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1882   Inst.addOperand(MCOperand::createImm(shift));
1883 
1884   return S;
1885 }
1886 
1887 static DecodeStatus
1888 DecodeAddrMode3Instruction(MCInst &Inst, unsigned Insn,
1889                            uint64_t Address, const void *Decoder) {
1890   DecodeStatus S = MCDisassembler::Success;
1891 
1892   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
1893   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1894   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1895   unsigned type = fieldFromInstruction(Insn, 22, 1);
1896   unsigned imm = fieldFromInstruction(Insn, 8, 4);
1897   unsigned U = ((~fieldFromInstruction(Insn, 23, 1)) & 1) << 8;
1898   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1899   unsigned W = fieldFromInstruction(Insn, 21, 1);
1900   unsigned P = fieldFromInstruction(Insn, 24, 1);
1901   unsigned Rt2 = Rt + 1;
1902 
1903   bool writeback = (W == 1) | (P == 0);
1904 
1905   // For {LD,ST}RD, Rt must be even, else undefined.
1906   switch (Inst.getOpcode()) {
1907     case ARM::STRD:
1908     case ARM::STRD_PRE:
1909     case ARM::STRD_POST:
1910     case ARM::LDRD:
1911     case ARM::LDRD_PRE:
1912     case ARM::LDRD_POST:
1913       if (Rt & 0x1) S = MCDisassembler::SoftFail;
1914       break;
1915     default:
1916       break;
1917   }
1918   switch (Inst.getOpcode()) {
1919     case ARM::STRD:
1920     case ARM::STRD_PRE:
1921     case ARM::STRD_POST:
1922       if (P == 0 && W == 1)
1923         S = MCDisassembler::SoftFail;
1924 
1925       if (writeback && (Rn == 15 || Rn == Rt || Rn == Rt2))
1926         S = MCDisassembler::SoftFail;
1927       if (type && Rm == 15)
1928         S = MCDisassembler::SoftFail;
1929       if (Rt2 == 15)
1930         S = MCDisassembler::SoftFail;
1931       if (!type && fieldFromInstruction(Insn, 8, 4))
1932         S = MCDisassembler::SoftFail;
1933       break;
1934     case ARM::STRH:
1935     case ARM::STRH_PRE:
1936     case ARM::STRH_POST:
1937       if (Rt == 15)
1938         S = MCDisassembler::SoftFail;
1939       if (writeback && (Rn == 15 || Rn == Rt))
1940         S = MCDisassembler::SoftFail;
1941       if (!type && Rm == 15)
1942         S = MCDisassembler::SoftFail;
1943       break;
1944     case ARM::LDRD:
1945     case ARM::LDRD_PRE:
1946     case ARM::LDRD_POST:
1947       if (type && Rn == 15) {
1948         if (Rt2 == 15)
1949           S = MCDisassembler::SoftFail;
1950         break;
1951       }
1952       if (P == 0 && W == 1)
1953         S = MCDisassembler::SoftFail;
1954       if (!type && (Rt2 == 15 || Rm == 15 || Rm == Rt || Rm == Rt2))
1955         S = MCDisassembler::SoftFail;
1956       if (!type && writeback && Rn == 15)
1957         S = MCDisassembler::SoftFail;
1958       if (writeback && (Rn == Rt || Rn == Rt2))
1959         S = MCDisassembler::SoftFail;
1960       break;
1961     case ARM::LDRH:
1962     case ARM::LDRH_PRE:
1963     case ARM::LDRH_POST:
1964       if (type && Rn == 15) {
1965         if (Rt == 15)
1966           S = MCDisassembler::SoftFail;
1967         break;
1968       }
1969       if (Rt == 15)
1970         S = MCDisassembler::SoftFail;
1971       if (!type && Rm == 15)
1972         S = MCDisassembler::SoftFail;
1973       if (!type && writeback && (Rn == 15 || Rn == Rt))
1974         S = MCDisassembler::SoftFail;
1975       break;
1976     case ARM::LDRSH:
1977     case ARM::LDRSH_PRE:
1978     case ARM::LDRSH_POST:
1979     case ARM::LDRSB:
1980     case ARM::LDRSB_PRE:
1981     case ARM::LDRSB_POST:
1982       if (type && Rn == 15) {
1983         if (Rt == 15)
1984           S = MCDisassembler::SoftFail;
1985         break;
1986       }
1987       if (type && (Rt == 15 || (writeback && Rn == Rt)))
1988         S = MCDisassembler::SoftFail;
1989       if (!type && (Rt == 15 || Rm == 15))
1990         S = MCDisassembler::SoftFail;
1991       if (!type && writeback && (Rn == 15 || Rn == Rt))
1992         S = MCDisassembler::SoftFail;
1993       break;
1994     default:
1995       break;
1996   }
1997 
1998   if (writeback) { // Writeback
1999     if (P)
2000       U |= ARMII::IndexModePre << 9;
2001     else
2002       U |= ARMII::IndexModePost << 9;
2003 
2004     // On stores, the writeback operand precedes Rt.
2005     switch (Inst.getOpcode()) {
2006     case ARM::STRD:
2007     case ARM::STRD_PRE:
2008     case ARM::STRD_POST:
2009     case ARM::STRH:
2010     case ARM::STRH_PRE:
2011     case ARM::STRH_POST:
2012       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2013         return MCDisassembler::Fail;
2014       break;
2015     default:
2016       break;
2017     }
2018   }
2019 
2020   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
2021     return MCDisassembler::Fail;
2022   switch (Inst.getOpcode()) {
2023     case ARM::STRD:
2024     case ARM::STRD_PRE:
2025     case ARM::STRD_POST:
2026     case ARM::LDRD:
2027     case ARM::LDRD_PRE:
2028     case ARM::LDRD_POST:
2029       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
2030         return MCDisassembler::Fail;
2031       break;
2032     default:
2033       break;
2034   }
2035 
2036   if (writeback) {
2037     // On loads, the writeback operand comes after Rt.
2038     switch (Inst.getOpcode()) {
2039     case ARM::LDRD:
2040     case ARM::LDRD_PRE:
2041     case ARM::LDRD_POST:
2042     case ARM::LDRH:
2043     case ARM::LDRH_PRE:
2044     case ARM::LDRH_POST:
2045     case ARM::LDRSH:
2046     case ARM::LDRSH_PRE:
2047     case ARM::LDRSH_POST:
2048     case ARM::LDRSB:
2049     case ARM::LDRSB_PRE:
2050     case ARM::LDRSB_POST:
2051     case ARM::LDRHTr:
2052     case ARM::LDRSBTr:
2053       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2054         return MCDisassembler::Fail;
2055       break;
2056     default:
2057       break;
2058     }
2059   }
2060 
2061   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2062     return MCDisassembler::Fail;
2063 
2064   if (type) {
2065     Inst.addOperand(MCOperand::createReg(0));
2066     Inst.addOperand(MCOperand::createImm(U | (imm << 4) | Rm));
2067   } else {
2068     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2069     return MCDisassembler::Fail;
2070     Inst.addOperand(MCOperand::createImm(U));
2071   }
2072 
2073   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2074     return MCDisassembler::Fail;
2075 
2076   return S;
2077 }
2078 
2079 static DecodeStatus DecodeRFEInstruction(MCInst &Inst, unsigned Insn,
2080                                  uint64_t Address, const void *Decoder) {
2081   DecodeStatus S = MCDisassembler::Success;
2082 
2083   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2084   unsigned mode = fieldFromInstruction(Insn, 23, 2);
2085 
2086   switch (mode) {
2087     case 0:
2088       mode = ARM_AM::da;
2089       break;
2090     case 1:
2091       mode = ARM_AM::ia;
2092       break;
2093     case 2:
2094       mode = ARM_AM::db;
2095       break;
2096     case 3:
2097       mode = ARM_AM::ib;
2098       break;
2099   }
2100 
2101   Inst.addOperand(MCOperand::createImm(mode));
2102   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2103     return MCDisassembler::Fail;
2104 
2105   return S;
2106 }
2107 
2108 static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
2109                                uint64_t Address, const void *Decoder) {
2110   DecodeStatus S = MCDisassembler::Success;
2111 
2112   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2113   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2114   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2115   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2116 
2117   if (pred == 0xF)
2118     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
2119 
2120   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2121     return MCDisassembler::Fail;
2122   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
2123     return MCDisassembler::Fail;
2124   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2125     return MCDisassembler::Fail;
2126   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2127     return MCDisassembler::Fail;
2128   return S;
2129 }
2130 
2131 static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst &Inst,
2132                                   unsigned Insn,
2133                                   uint64_t Address, const void *Decoder) {
2134   DecodeStatus S = MCDisassembler::Success;
2135 
2136   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2137   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2138   unsigned reglist = fieldFromInstruction(Insn, 0, 16);
2139 
2140   if (pred == 0xF) {
2141     // Ambiguous with RFE and SRS
2142     switch (Inst.getOpcode()) {
2143       case ARM::LDMDA:
2144         Inst.setOpcode(ARM::RFEDA);
2145         break;
2146       case ARM::LDMDA_UPD:
2147         Inst.setOpcode(ARM::RFEDA_UPD);
2148         break;
2149       case ARM::LDMDB:
2150         Inst.setOpcode(ARM::RFEDB);
2151         break;
2152       case ARM::LDMDB_UPD:
2153         Inst.setOpcode(ARM::RFEDB_UPD);
2154         break;
2155       case ARM::LDMIA:
2156         Inst.setOpcode(ARM::RFEIA);
2157         break;
2158       case ARM::LDMIA_UPD:
2159         Inst.setOpcode(ARM::RFEIA_UPD);
2160         break;
2161       case ARM::LDMIB:
2162         Inst.setOpcode(ARM::RFEIB);
2163         break;
2164       case ARM::LDMIB_UPD:
2165         Inst.setOpcode(ARM::RFEIB_UPD);
2166         break;
2167       case ARM::STMDA:
2168         Inst.setOpcode(ARM::SRSDA);
2169         break;
2170       case ARM::STMDA_UPD:
2171         Inst.setOpcode(ARM::SRSDA_UPD);
2172         break;
2173       case ARM::STMDB:
2174         Inst.setOpcode(ARM::SRSDB);
2175         break;
2176       case ARM::STMDB_UPD:
2177         Inst.setOpcode(ARM::SRSDB_UPD);
2178         break;
2179       case ARM::STMIA:
2180         Inst.setOpcode(ARM::SRSIA);
2181         break;
2182       case ARM::STMIA_UPD:
2183         Inst.setOpcode(ARM::SRSIA_UPD);
2184         break;
2185       case ARM::STMIB:
2186         Inst.setOpcode(ARM::SRSIB);
2187         break;
2188       case ARM::STMIB_UPD:
2189         Inst.setOpcode(ARM::SRSIB_UPD);
2190         break;
2191       default:
2192         return MCDisassembler::Fail;
2193     }
2194 
2195     // For stores (which become SRS's, the only operand is the mode.
2196     if (fieldFromInstruction(Insn, 20, 1) == 0) {
2197       // Check SRS encoding constraints
2198       if (!(fieldFromInstruction(Insn, 22, 1) == 1 &&
2199             fieldFromInstruction(Insn, 20, 1) == 0))
2200         return MCDisassembler::Fail;
2201 
2202       Inst.addOperand(
2203           MCOperand::createImm(fieldFromInstruction(Insn, 0, 4)));
2204       return S;
2205     }
2206 
2207     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
2208   }
2209 
2210   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2211     return MCDisassembler::Fail;
2212   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2213     return MCDisassembler::Fail; // Tied
2214   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2215     return MCDisassembler::Fail;
2216   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
2217     return MCDisassembler::Fail;
2218 
2219   return S;
2220 }
2221 
2222 // Check for UNPREDICTABLE predicated ESB instruction
2223 static DecodeStatus DecodeHINTInstruction(MCInst &Inst, unsigned Insn,
2224                                  uint64_t Address, const void *Decoder) {
2225   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2226   unsigned imm8 = fieldFromInstruction(Insn, 0, 8);
2227   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
2228   const FeatureBitset &FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
2229 
2230   DecodeStatus S = MCDisassembler::Success;
2231 
2232   Inst.addOperand(MCOperand::createImm(imm8));
2233 
2234   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2235     return MCDisassembler::Fail;
2236 
2237   // ESB is unpredictable if pred != AL. Without the RAS extension, it is a NOP,
2238   // so all predicates should be allowed.
2239   if (imm8 == 0x10 && pred != 0xe && ((FeatureBits[ARM::FeatureRAS]) != 0))
2240     S = MCDisassembler::SoftFail;
2241 
2242   return S;
2243 }
2244 
2245 static DecodeStatus DecodeCPSInstruction(MCInst &Inst, unsigned Insn,
2246                                  uint64_t Address, const void *Decoder) {
2247   unsigned imod = fieldFromInstruction(Insn, 18, 2);
2248   unsigned M = fieldFromInstruction(Insn, 17, 1);
2249   unsigned iflags = fieldFromInstruction(Insn, 6, 3);
2250   unsigned mode = fieldFromInstruction(Insn, 0, 5);
2251 
2252   DecodeStatus S = MCDisassembler::Success;
2253 
2254   // This decoder is called from multiple location that do not check
2255   // the full encoding is valid before they do.
2256   if (fieldFromInstruction(Insn, 5, 1) != 0 ||
2257       fieldFromInstruction(Insn, 16, 1) != 0 ||
2258       fieldFromInstruction(Insn, 20, 8) != 0x10)
2259     return MCDisassembler::Fail;
2260 
2261   // imod == '01' --> UNPREDICTABLE
2262   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
2263   // return failure here.  The '01' imod value is unprintable, so there's
2264   // nothing useful we could do even if we returned UNPREDICTABLE.
2265 
2266   if (imod == 1) return MCDisassembler::Fail;
2267 
2268   if (imod && M) {
2269     Inst.setOpcode(ARM::CPS3p);
2270     Inst.addOperand(MCOperand::createImm(imod));
2271     Inst.addOperand(MCOperand::createImm(iflags));
2272     Inst.addOperand(MCOperand::createImm(mode));
2273   } else if (imod && !M) {
2274     Inst.setOpcode(ARM::CPS2p);
2275     Inst.addOperand(MCOperand::createImm(imod));
2276     Inst.addOperand(MCOperand::createImm(iflags));
2277     if (mode) S = MCDisassembler::SoftFail;
2278   } else if (!imod && M) {
2279     Inst.setOpcode(ARM::CPS1p);
2280     Inst.addOperand(MCOperand::createImm(mode));
2281     if (iflags) S = MCDisassembler::SoftFail;
2282   } else {
2283     // imod == '00' && M == '0' --> UNPREDICTABLE
2284     Inst.setOpcode(ARM::CPS1p);
2285     Inst.addOperand(MCOperand::createImm(mode));
2286     S = MCDisassembler::SoftFail;
2287   }
2288 
2289   return S;
2290 }
2291 
2292 static DecodeStatus DecodeT2CPSInstruction(MCInst &Inst, unsigned Insn,
2293                                  uint64_t Address, const void *Decoder) {
2294   unsigned imod = fieldFromInstruction(Insn, 9, 2);
2295   unsigned M = fieldFromInstruction(Insn, 8, 1);
2296   unsigned iflags = fieldFromInstruction(Insn, 5, 3);
2297   unsigned mode = fieldFromInstruction(Insn, 0, 5);
2298 
2299   DecodeStatus S = MCDisassembler::Success;
2300 
2301   // imod == '01' --> UNPREDICTABLE
2302   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
2303   // return failure here.  The '01' imod value is unprintable, so there's
2304   // nothing useful we could do even if we returned UNPREDICTABLE.
2305 
2306   if (imod == 1) return MCDisassembler::Fail;
2307 
2308   if (imod && M) {
2309     Inst.setOpcode(ARM::t2CPS3p);
2310     Inst.addOperand(MCOperand::createImm(imod));
2311     Inst.addOperand(MCOperand::createImm(iflags));
2312     Inst.addOperand(MCOperand::createImm(mode));
2313   } else if (imod && !M) {
2314     Inst.setOpcode(ARM::t2CPS2p);
2315     Inst.addOperand(MCOperand::createImm(imod));
2316     Inst.addOperand(MCOperand::createImm(iflags));
2317     if (mode) S = MCDisassembler::SoftFail;
2318   } else if (!imod && M) {
2319     Inst.setOpcode(ARM::t2CPS1p);
2320     Inst.addOperand(MCOperand::createImm(mode));
2321     if (iflags) S = MCDisassembler::SoftFail;
2322   } else {
2323     // imod == '00' && M == '0' --> this is a HINT instruction
2324     int imm = fieldFromInstruction(Insn, 0, 8);
2325     // HINT are defined only for immediate in [0..4]
2326     if(imm > 4) return MCDisassembler::Fail;
2327     Inst.setOpcode(ARM::t2HINT);
2328     Inst.addOperand(MCOperand::createImm(imm));
2329   }
2330 
2331   return S;
2332 }
2333 
2334 static DecodeStatus DecodeT2MOVTWInstruction(MCInst &Inst, unsigned Insn,
2335                                  uint64_t Address, const void *Decoder) {
2336   DecodeStatus S = MCDisassembler::Success;
2337 
2338   unsigned Rd = fieldFromInstruction(Insn, 8, 4);
2339   unsigned imm = 0;
2340 
2341   imm |= (fieldFromInstruction(Insn, 0, 8) << 0);
2342   imm |= (fieldFromInstruction(Insn, 12, 3) << 8);
2343   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
2344   imm |= (fieldFromInstruction(Insn, 26, 1) << 11);
2345 
2346   if (Inst.getOpcode() == ARM::t2MOVTi16)
2347     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2348       return MCDisassembler::Fail;
2349   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2350     return MCDisassembler::Fail;
2351 
2352   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
2353     Inst.addOperand(MCOperand::createImm(imm));
2354 
2355   return S;
2356 }
2357 
2358 static DecodeStatus DecodeArmMOVTWInstruction(MCInst &Inst, unsigned Insn,
2359                                  uint64_t Address, const void *Decoder) {
2360   DecodeStatus S = MCDisassembler::Success;
2361 
2362   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2363   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2364   unsigned imm = 0;
2365 
2366   imm |= (fieldFromInstruction(Insn, 0, 12) << 0);
2367   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
2368 
2369   if (Inst.getOpcode() == ARM::MOVTi16)
2370     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2371       return MCDisassembler::Fail;
2372 
2373   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2374     return MCDisassembler::Fail;
2375 
2376   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
2377     Inst.addOperand(MCOperand::createImm(imm));
2378 
2379   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2380     return MCDisassembler::Fail;
2381 
2382   return S;
2383 }
2384 
2385 static DecodeStatus DecodeSMLAInstruction(MCInst &Inst, unsigned Insn,
2386                                  uint64_t Address, const void *Decoder) {
2387   DecodeStatus S = MCDisassembler::Success;
2388 
2389   unsigned Rd = fieldFromInstruction(Insn, 16, 4);
2390   unsigned Rn = fieldFromInstruction(Insn, 0, 4);
2391   unsigned Rm = fieldFromInstruction(Insn, 8, 4);
2392   unsigned Ra = fieldFromInstruction(Insn, 12, 4);
2393   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2394 
2395   if (pred == 0xF)
2396     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
2397 
2398   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2399     return MCDisassembler::Fail;
2400   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2401     return MCDisassembler::Fail;
2402   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
2403     return MCDisassembler::Fail;
2404   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
2405     return MCDisassembler::Fail;
2406 
2407   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2408     return MCDisassembler::Fail;
2409 
2410   return S;
2411 }
2412 
2413 static DecodeStatus DecodeTSTInstruction(MCInst &Inst, unsigned Insn,
2414                                   uint64_t Address, const void *Decoder) {
2415   DecodeStatus S = MCDisassembler::Success;
2416 
2417   unsigned Pred = fieldFromInstruction(Insn, 28, 4);
2418   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2419   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2420 
2421   if (Pred == 0xF)
2422     return DecodeSETPANInstruction(Inst, Insn, Address, Decoder);
2423 
2424   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2425     return MCDisassembler::Fail;
2426   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2427     return MCDisassembler::Fail;
2428   if (!Check(S, DecodePredicateOperand(Inst, Pred, Address, Decoder)))
2429     return MCDisassembler::Fail;
2430 
2431   return S;
2432 }
2433 
2434 static DecodeStatus DecodeSETPANInstruction(MCInst &Inst, unsigned Insn,
2435                                   uint64_t Address, const void *Decoder) {
2436   DecodeStatus S = MCDisassembler::Success;
2437 
2438   unsigned Imm = fieldFromInstruction(Insn, 9, 1);
2439 
2440   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
2441   const FeatureBitset &FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
2442 
2443   if (!FeatureBits[ARM::HasV8_1aOps] ||
2444       !FeatureBits[ARM::HasV8Ops])
2445     return MCDisassembler::Fail;
2446 
2447   // Decoder can be called from DecodeTST, which does not check the full
2448   // encoding is valid.
2449   if (fieldFromInstruction(Insn, 20,12) != 0xf11 ||
2450       fieldFromInstruction(Insn, 4,4) != 0)
2451     return MCDisassembler::Fail;
2452   if (fieldFromInstruction(Insn, 10,10) != 0 ||
2453       fieldFromInstruction(Insn, 0,4) != 0)
2454     S = MCDisassembler::SoftFail;
2455 
2456   Inst.setOpcode(ARM::SETPAN);
2457   Inst.addOperand(MCOperand::createImm(Imm));
2458 
2459   return S;
2460 }
2461 
2462 static DecodeStatus DecodeAddrModeImm12Operand(MCInst &Inst, unsigned Val,
2463                            uint64_t Address, const void *Decoder) {
2464   DecodeStatus S = MCDisassembler::Success;
2465 
2466   unsigned add = fieldFromInstruction(Val, 12, 1);
2467   unsigned imm = fieldFromInstruction(Val, 0, 12);
2468   unsigned Rn = fieldFromInstruction(Val, 13, 4);
2469 
2470   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2471     return MCDisassembler::Fail;
2472 
2473   if (!add) imm *= -1;
2474   if (imm == 0 && !add) imm = INT32_MIN;
2475   Inst.addOperand(MCOperand::createImm(imm));
2476   if (Rn == 15)
2477     tryAddingPcLoadReferenceComment(Address, Address + imm + 8, Decoder);
2478 
2479   return S;
2480 }
2481 
2482 static DecodeStatus DecodeAddrMode5Operand(MCInst &Inst, unsigned Val,
2483                                    uint64_t Address, const void *Decoder) {
2484   DecodeStatus S = MCDisassembler::Success;
2485 
2486   unsigned Rn = fieldFromInstruction(Val, 9, 4);
2487   // U == 1 to add imm, 0 to subtract it.
2488   unsigned U = fieldFromInstruction(Val, 8, 1);
2489   unsigned imm = fieldFromInstruction(Val, 0, 8);
2490 
2491   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2492     return MCDisassembler::Fail;
2493 
2494   if (U)
2495     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
2496   else
2497     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
2498 
2499   return S;
2500 }
2501 
2502 static DecodeStatus DecodeAddrMode5FP16Operand(MCInst &Inst, unsigned Val,
2503                                    uint64_t Address, const void *Decoder) {
2504   DecodeStatus S = MCDisassembler::Success;
2505 
2506   unsigned Rn = fieldFromInstruction(Val, 9, 4);
2507   // U == 1 to add imm, 0 to subtract it.
2508   unsigned U = fieldFromInstruction(Val, 8, 1);
2509   unsigned imm = fieldFromInstruction(Val, 0, 8);
2510 
2511   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2512     return MCDisassembler::Fail;
2513 
2514   if (U)
2515     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5FP16Opc(ARM_AM::add, imm)));
2516   else
2517     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5FP16Opc(ARM_AM::sub, imm)));
2518 
2519   return S;
2520 }
2521 
2522 static DecodeStatus DecodeAddrMode7Operand(MCInst &Inst, unsigned Val,
2523                                    uint64_t Address, const void *Decoder) {
2524   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
2525 }
2526 
2527 static DecodeStatus
2528 DecodeT2BInstruction(MCInst &Inst, unsigned Insn,
2529                      uint64_t Address, const void *Decoder) {
2530   DecodeStatus Status = MCDisassembler::Success;
2531 
2532   // Note the J1 and J2 values are from the encoded instruction.  So here
2533   // change them to I1 and I2 values via as documented:
2534   // I1 = NOT(J1 EOR S);
2535   // I2 = NOT(J2 EOR S);
2536   // and build the imm32 with one trailing zero as documented:
2537   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
2538   unsigned S = fieldFromInstruction(Insn, 26, 1);
2539   unsigned J1 = fieldFromInstruction(Insn, 13, 1);
2540   unsigned J2 = fieldFromInstruction(Insn, 11, 1);
2541   unsigned I1 = !(J1 ^ S);
2542   unsigned I2 = !(J2 ^ S);
2543   unsigned imm10 = fieldFromInstruction(Insn, 16, 10);
2544   unsigned imm11 = fieldFromInstruction(Insn, 0, 11);
2545   unsigned tmp = (S << 23) | (I1 << 22) | (I2 << 21) | (imm10 << 11) | imm11;
2546   int imm32 = SignExtend32<25>(tmp << 1);
2547   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
2548                                 true, 4, Inst, Decoder))
2549     Inst.addOperand(MCOperand::createImm(imm32));
2550 
2551   return Status;
2552 }
2553 
2554 static DecodeStatus
2555 DecodeBranchImmInstruction(MCInst &Inst, unsigned Insn,
2556                            uint64_t Address, const void *Decoder) {
2557   DecodeStatus S = MCDisassembler::Success;
2558 
2559   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2560   unsigned imm = fieldFromInstruction(Insn, 0, 24) << 2;
2561 
2562   if (pred == 0xF) {
2563     Inst.setOpcode(ARM::BLXi);
2564     imm |= fieldFromInstruction(Insn, 24, 1) << 1;
2565     if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
2566                                   true, 4, Inst, Decoder))
2567     Inst.addOperand(MCOperand::createImm(SignExtend32<26>(imm)));
2568     return S;
2569   }
2570 
2571   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
2572                                 true, 4, Inst, Decoder))
2573     Inst.addOperand(MCOperand::createImm(SignExtend32<26>(imm)));
2574   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2575     return MCDisassembler::Fail;
2576 
2577   return S;
2578 }
2579 
2580 static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
2581                                    uint64_t Address, const void *Decoder) {
2582   DecodeStatus S = MCDisassembler::Success;
2583 
2584   unsigned Rm = fieldFromInstruction(Val, 0, 4);
2585   unsigned align = fieldFromInstruction(Val, 4, 2);
2586 
2587   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2588     return MCDisassembler::Fail;
2589   if (!align)
2590     Inst.addOperand(MCOperand::createImm(0));
2591   else
2592     Inst.addOperand(MCOperand::createImm(4 << align));
2593 
2594   return S;
2595 }
2596 
2597 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Insn,
2598                                    uint64_t Address, const void *Decoder) {
2599   DecodeStatus S = MCDisassembler::Success;
2600 
2601   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2602   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2603   unsigned wb = fieldFromInstruction(Insn, 16, 4);
2604   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2605   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
2606   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2607 
2608   // First output register
2609   switch (Inst.getOpcode()) {
2610   case ARM::VLD1q16: case ARM::VLD1q32: case ARM::VLD1q64: case ARM::VLD1q8:
2611   case ARM::VLD1q16wb_fixed: case ARM::VLD1q16wb_register:
2612   case ARM::VLD1q32wb_fixed: case ARM::VLD1q32wb_register:
2613   case ARM::VLD1q64wb_fixed: case ARM::VLD1q64wb_register:
2614   case ARM::VLD1q8wb_fixed: case ARM::VLD1q8wb_register:
2615   case ARM::VLD2d16: case ARM::VLD2d32: case ARM::VLD2d8:
2616   case ARM::VLD2d16wb_fixed: case ARM::VLD2d16wb_register:
2617   case ARM::VLD2d32wb_fixed: case ARM::VLD2d32wb_register:
2618   case ARM::VLD2d8wb_fixed: case ARM::VLD2d8wb_register:
2619     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2620       return MCDisassembler::Fail;
2621     break;
2622   case ARM::VLD2b16:
2623   case ARM::VLD2b32:
2624   case ARM::VLD2b8:
2625   case ARM::VLD2b16wb_fixed:
2626   case ARM::VLD2b16wb_register:
2627   case ARM::VLD2b32wb_fixed:
2628   case ARM::VLD2b32wb_register:
2629   case ARM::VLD2b8wb_fixed:
2630   case ARM::VLD2b8wb_register:
2631     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
2632       return MCDisassembler::Fail;
2633     break;
2634   default:
2635     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2636       return MCDisassembler::Fail;
2637   }
2638 
2639   // Second output register
2640   switch (Inst.getOpcode()) {
2641     case ARM::VLD3d8:
2642     case ARM::VLD3d16:
2643     case ARM::VLD3d32:
2644     case ARM::VLD3d8_UPD:
2645     case ARM::VLD3d16_UPD:
2646     case ARM::VLD3d32_UPD:
2647     case ARM::VLD4d8:
2648     case ARM::VLD4d16:
2649     case ARM::VLD4d32:
2650     case ARM::VLD4d8_UPD:
2651     case ARM::VLD4d16_UPD:
2652     case ARM::VLD4d32_UPD:
2653       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2654         return MCDisassembler::Fail;
2655       break;
2656     case ARM::VLD3q8:
2657     case ARM::VLD3q16:
2658     case ARM::VLD3q32:
2659     case ARM::VLD3q8_UPD:
2660     case ARM::VLD3q16_UPD:
2661     case ARM::VLD3q32_UPD:
2662     case ARM::VLD4q8:
2663     case ARM::VLD4q16:
2664     case ARM::VLD4q32:
2665     case ARM::VLD4q8_UPD:
2666     case ARM::VLD4q16_UPD:
2667     case ARM::VLD4q32_UPD:
2668       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2669         return MCDisassembler::Fail;
2670       break;
2671     default:
2672       break;
2673   }
2674 
2675   // Third output register
2676   switch(Inst.getOpcode()) {
2677     case ARM::VLD3d8:
2678     case ARM::VLD3d16:
2679     case ARM::VLD3d32:
2680     case ARM::VLD3d8_UPD:
2681     case ARM::VLD3d16_UPD:
2682     case ARM::VLD3d32_UPD:
2683     case ARM::VLD4d8:
2684     case ARM::VLD4d16:
2685     case ARM::VLD4d32:
2686     case ARM::VLD4d8_UPD:
2687     case ARM::VLD4d16_UPD:
2688     case ARM::VLD4d32_UPD:
2689       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2690         return MCDisassembler::Fail;
2691       break;
2692     case ARM::VLD3q8:
2693     case ARM::VLD3q16:
2694     case ARM::VLD3q32:
2695     case ARM::VLD3q8_UPD:
2696     case ARM::VLD3q16_UPD:
2697     case ARM::VLD3q32_UPD:
2698     case ARM::VLD4q8:
2699     case ARM::VLD4q16:
2700     case ARM::VLD4q32:
2701     case ARM::VLD4q8_UPD:
2702     case ARM::VLD4q16_UPD:
2703     case ARM::VLD4q32_UPD:
2704       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2705         return MCDisassembler::Fail;
2706       break;
2707     default:
2708       break;
2709   }
2710 
2711   // Fourth output register
2712   switch (Inst.getOpcode()) {
2713     case ARM::VLD4d8:
2714     case ARM::VLD4d16:
2715     case ARM::VLD4d32:
2716     case ARM::VLD4d8_UPD:
2717     case ARM::VLD4d16_UPD:
2718     case ARM::VLD4d32_UPD:
2719       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2720         return MCDisassembler::Fail;
2721       break;
2722     case ARM::VLD4q8:
2723     case ARM::VLD4q16:
2724     case ARM::VLD4q32:
2725     case ARM::VLD4q8_UPD:
2726     case ARM::VLD4q16_UPD:
2727     case ARM::VLD4q32_UPD:
2728       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2729         return MCDisassembler::Fail;
2730       break;
2731     default:
2732       break;
2733   }
2734 
2735   // Writeback operand
2736   switch (Inst.getOpcode()) {
2737     case ARM::VLD1d8wb_fixed:
2738     case ARM::VLD1d16wb_fixed:
2739     case ARM::VLD1d32wb_fixed:
2740     case ARM::VLD1d64wb_fixed:
2741     case ARM::VLD1d8wb_register:
2742     case ARM::VLD1d16wb_register:
2743     case ARM::VLD1d32wb_register:
2744     case ARM::VLD1d64wb_register:
2745     case ARM::VLD1q8wb_fixed:
2746     case ARM::VLD1q16wb_fixed:
2747     case ARM::VLD1q32wb_fixed:
2748     case ARM::VLD1q64wb_fixed:
2749     case ARM::VLD1q8wb_register:
2750     case ARM::VLD1q16wb_register:
2751     case ARM::VLD1q32wb_register:
2752     case ARM::VLD1q64wb_register:
2753     case ARM::VLD1d8Twb_fixed:
2754     case ARM::VLD1d8Twb_register:
2755     case ARM::VLD1d16Twb_fixed:
2756     case ARM::VLD1d16Twb_register:
2757     case ARM::VLD1d32Twb_fixed:
2758     case ARM::VLD1d32Twb_register:
2759     case ARM::VLD1d64Twb_fixed:
2760     case ARM::VLD1d64Twb_register:
2761     case ARM::VLD1d8Qwb_fixed:
2762     case ARM::VLD1d8Qwb_register:
2763     case ARM::VLD1d16Qwb_fixed:
2764     case ARM::VLD1d16Qwb_register:
2765     case ARM::VLD1d32Qwb_fixed:
2766     case ARM::VLD1d32Qwb_register:
2767     case ARM::VLD1d64Qwb_fixed:
2768     case ARM::VLD1d64Qwb_register:
2769     case ARM::VLD2d8wb_fixed:
2770     case ARM::VLD2d16wb_fixed:
2771     case ARM::VLD2d32wb_fixed:
2772     case ARM::VLD2q8wb_fixed:
2773     case ARM::VLD2q16wb_fixed:
2774     case ARM::VLD2q32wb_fixed:
2775     case ARM::VLD2d8wb_register:
2776     case ARM::VLD2d16wb_register:
2777     case ARM::VLD2d32wb_register:
2778     case ARM::VLD2q8wb_register:
2779     case ARM::VLD2q16wb_register:
2780     case ARM::VLD2q32wb_register:
2781     case ARM::VLD2b8wb_fixed:
2782     case ARM::VLD2b16wb_fixed:
2783     case ARM::VLD2b32wb_fixed:
2784     case ARM::VLD2b8wb_register:
2785     case ARM::VLD2b16wb_register:
2786     case ARM::VLD2b32wb_register:
2787       Inst.addOperand(MCOperand::createImm(0));
2788       break;
2789     case ARM::VLD3d8_UPD:
2790     case ARM::VLD3d16_UPD:
2791     case ARM::VLD3d32_UPD:
2792     case ARM::VLD3q8_UPD:
2793     case ARM::VLD3q16_UPD:
2794     case ARM::VLD3q32_UPD:
2795     case ARM::VLD4d8_UPD:
2796     case ARM::VLD4d16_UPD:
2797     case ARM::VLD4d32_UPD:
2798     case ARM::VLD4q8_UPD:
2799     case ARM::VLD4q16_UPD:
2800     case ARM::VLD4q32_UPD:
2801       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2802         return MCDisassembler::Fail;
2803       break;
2804     default:
2805       break;
2806   }
2807 
2808   // AddrMode6 Base (register+alignment)
2809   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2810     return MCDisassembler::Fail;
2811 
2812   // AddrMode6 Offset (register)
2813   switch (Inst.getOpcode()) {
2814   default:
2815     // The below have been updated to have explicit am6offset split
2816     // between fixed and register offset. For those instructions not
2817     // yet updated, we need to add an additional reg0 operand for the
2818     // fixed variant.
2819     //
2820     // The fixed offset encodes as Rm == 0xd, so we check for that.
2821     if (Rm == 0xd) {
2822       Inst.addOperand(MCOperand::createReg(0));
2823       break;
2824     }
2825     // Fall through to handle the register offset variant.
2826     LLVM_FALLTHROUGH;
2827   case ARM::VLD1d8wb_fixed:
2828   case ARM::VLD1d16wb_fixed:
2829   case ARM::VLD1d32wb_fixed:
2830   case ARM::VLD1d64wb_fixed:
2831   case ARM::VLD1d8Twb_fixed:
2832   case ARM::VLD1d16Twb_fixed:
2833   case ARM::VLD1d32Twb_fixed:
2834   case ARM::VLD1d64Twb_fixed:
2835   case ARM::VLD1d8Qwb_fixed:
2836   case ARM::VLD1d16Qwb_fixed:
2837   case ARM::VLD1d32Qwb_fixed:
2838   case ARM::VLD1d64Qwb_fixed:
2839   case ARM::VLD1d8wb_register:
2840   case ARM::VLD1d16wb_register:
2841   case ARM::VLD1d32wb_register:
2842   case ARM::VLD1d64wb_register:
2843   case ARM::VLD1q8wb_fixed:
2844   case ARM::VLD1q16wb_fixed:
2845   case ARM::VLD1q32wb_fixed:
2846   case ARM::VLD1q64wb_fixed:
2847   case ARM::VLD1q8wb_register:
2848   case ARM::VLD1q16wb_register:
2849   case ARM::VLD1q32wb_register:
2850   case ARM::VLD1q64wb_register:
2851     // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2852     // variant encodes Rm == 0xf. Anything else is a register offset post-
2853     // increment and we need to add the register operand to the instruction.
2854     if (Rm != 0xD && Rm != 0xF &&
2855         !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2856       return MCDisassembler::Fail;
2857     break;
2858   case ARM::VLD2d8wb_fixed:
2859   case ARM::VLD2d16wb_fixed:
2860   case ARM::VLD2d32wb_fixed:
2861   case ARM::VLD2b8wb_fixed:
2862   case ARM::VLD2b16wb_fixed:
2863   case ARM::VLD2b32wb_fixed:
2864   case ARM::VLD2q8wb_fixed:
2865   case ARM::VLD2q16wb_fixed:
2866   case ARM::VLD2q32wb_fixed:
2867     break;
2868   }
2869 
2870   return S;
2871 }
2872 
2873 static DecodeStatus DecodeVLDST1Instruction(MCInst &Inst, unsigned Insn,
2874                                    uint64_t Address, const void *Decoder) {
2875   unsigned type = fieldFromInstruction(Insn, 8, 4);
2876   unsigned align = fieldFromInstruction(Insn, 4, 2);
2877   if (type == 6 && (align & 2)) return MCDisassembler::Fail;
2878   if (type == 7 && (align & 2)) return MCDisassembler::Fail;
2879   if (type == 10 && align == 3) return MCDisassembler::Fail;
2880 
2881   unsigned load = fieldFromInstruction(Insn, 21, 1);
2882   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2883               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2884 }
2885 
2886 static DecodeStatus DecodeVLDST2Instruction(MCInst &Inst, unsigned Insn,
2887                                    uint64_t Address, const void *Decoder) {
2888   unsigned size = fieldFromInstruction(Insn, 6, 2);
2889   if (size == 3) return MCDisassembler::Fail;
2890 
2891   unsigned type = fieldFromInstruction(Insn, 8, 4);
2892   unsigned align = fieldFromInstruction(Insn, 4, 2);
2893   if (type == 8 && align == 3) return MCDisassembler::Fail;
2894   if (type == 9 && align == 3) return MCDisassembler::Fail;
2895 
2896   unsigned load = fieldFromInstruction(Insn, 21, 1);
2897   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2898               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2899 }
2900 
2901 static DecodeStatus DecodeVLDST3Instruction(MCInst &Inst, unsigned Insn,
2902                                    uint64_t Address, const void *Decoder) {
2903   unsigned size = fieldFromInstruction(Insn, 6, 2);
2904   if (size == 3) return MCDisassembler::Fail;
2905 
2906   unsigned align = fieldFromInstruction(Insn, 4, 2);
2907   if (align & 2) return MCDisassembler::Fail;
2908 
2909   unsigned load = fieldFromInstruction(Insn, 21, 1);
2910   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2911               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2912 }
2913 
2914 static DecodeStatus DecodeVLDST4Instruction(MCInst &Inst, unsigned Insn,
2915                                    uint64_t Address, const void *Decoder) {
2916   unsigned size = fieldFromInstruction(Insn, 6, 2);
2917   if (size == 3) return MCDisassembler::Fail;
2918 
2919   unsigned load = fieldFromInstruction(Insn, 21, 1);
2920   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2921               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2922 }
2923 
2924 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Insn,
2925                                  uint64_t Address, const void *Decoder) {
2926   DecodeStatus S = MCDisassembler::Success;
2927 
2928   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2929   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2930   unsigned wb = fieldFromInstruction(Insn, 16, 4);
2931   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2932   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
2933   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2934 
2935   // Writeback Operand
2936   switch (Inst.getOpcode()) {
2937     case ARM::VST1d8wb_fixed:
2938     case ARM::VST1d16wb_fixed:
2939     case ARM::VST1d32wb_fixed:
2940     case ARM::VST1d64wb_fixed:
2941     case ARM::VST1d8wb_register:
2942     case ARM::VST1d16wb_register:
2943     case ARM::VST1d32wb_register:
2944     case ARM::VST1d64wb_register:
2945     case ARM::VST1q8wb_fixed:
2946     case ARM::VST1q16wb_fixed:
2947     case ARM::VST1q32wb_fixed:
2948     case ARM::VST1q64wb_fixed:
2949     case ARM::VST1q8wb_register:
2950     case ARM::VST1q16wb_register:
2951     case ARM::VST1q32wb_register:
2952     case ARM::VST1q64wb_register:
2953     case ARM::VST1d8Twb_fixed:
2954     case ARM::VST1d16Twb_fixed:
2955     case ARM::VST1d32Twb_fixed:
2956     case ARM::VST1d64Twb_fixed:
2957     case ARM::VST1d8Twb_register:
2958     case ARM::VST1d16Twb_register:
2959     case ARM::VST1d32Twb_register:
2960     case ARM::VST1d64Twb_register:
2961     case ARM::VST1d8Qwb_fixed:
2962     case ARM::VST1d16Qwb_fixed:
2963     case ARM::VST1d32Qwb_fixed:
2964     case ARM::VST1d64Qwb_fixed:
2965     case ARM::VST1d8Qwb_register:
2966     case ARM::VST1d16Qwb_register:
2967     case ARM::VST1d32Qwb_register:
2968     case ARM::VST1d64Qwb_register:
2969     case ARM::VST2d8wb_fixed:
2970     case ARM::VST2d16wb_fixed:
2971     case ARM::VST2d32wb_fixed:
2972     case ARM::VST2d8wb_register:
2973     case ARM::VST2d16wb_register:
2974     case ARM::VST2d32wb_register:
2975     case ARM::VST2q8wb_fixed:
2976     case ARM::VST2q16wb_fixed:
2977     case ARM::VST2q32wb_fixed:
2978     case ARM::VST2q8wb_register:
2979     case ARM::VST2q16wb_register:
2980     case ARM::VST2q32wb_register:
2981     case ARM::VST2b8wb_fixed:
2982     case ARM::VST2b16wb_fixed:
2983     case ARM::VST2b32wb_fixed:
2984     case ARM::VST2b8wb_register:
2985     case ARM::VST2b16wb_register:
2986     case ARM::VST2b32wb_register:
2987       if (Rm == 0xF)
2988         return MCDisassembler::Fail;
2989       Inst.addOperand(MCOperand::createImm(0));
2990       break;
2991     case ARM::VST3d8_UPD:
2992     case ARM::VST3d16_UPD:
2993     case ARM::VST3d32_UPD:
2994     case ARM::VST3q8_UPD:
2995     case ARM::VST3q16_UPD:
2996     case ARM::VST3q32_UPD:
2997     case ARM::VST4d8_UPD:
2998     case ARM::VST4d16_UPD:
2999     case ARM::VST4d32_UPD:
3000     case ARM::VST4q8_UPD:
3001     case ARM::VST4q16_UPD:
3002     case ARM::VST4q32_UPD:
3003       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
3004         return MCDisassembler::Fail;
3005       break;
3006     default:
3007       break;
3008   }
3009 
3010   // AddrMode6 Base (register+alignment)
3011   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
3012     return MCDisassembler::Fail;
3013 
3014   // AddrMode6 Offset (register)
3015   switch (Inst.getOpcode()) {
3016     default:
3017       if (Rm == 0xD)
3018         Inst.addOperand(MCOperand::createReg(0));
3019       else if (Rm != 0xF) {
3020         if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3021           return MCDisassembler::Fail;
3022       }
3023       break;
3024     case ARM::VST1d8wb_fixed:
3025     case ARM::VST1d16wb_fixed:
3026     case ARM::VST1d32wb_fixed:
3027     case ARM::VST1d64wb_fixed:
3028     case ARM::VST1q8wb_fixed:
3029     case ARM::VST1q16wb_fixed:
3030     case ARM::VST1q32wb_fixed:
3031     case ARM::VST1q64wb_fixed:
3032     case ARM::VST1d8Twb_fixed:
3033     case ARM::VST1d16Twb_fixed:
3034     case ARM::VST1d32Twb_fixed:
3035     case ARM::VST1d64Twb_fixed:
3036     case ARM::VST1d8Qwb_fixed:
3037     case ARM::VST1d16Qwb_fixed:
3038     case ARM::VST1d32Qwb_fixed:
3039     case ARM::VST1d64Qwb_fixed:
3040     case ARM::VST2d8wb_fixed:
3041     case ARM::VST2d16wb_fixed:
3042     case ARM::VST2d32wb_fixed:
3043     case ARM::VST2q8wb_fixed:
3044     case ARM::VST2q16wb_fixed:
3045     case ARM::VST2q32wb_fixed:
3046     case ARM::VST2b8wb_fixed:
3047     case ARM::VST2b16wb_fixed:
3048     case ARM::VST2b32wb_fixed:
3049       break;
3050   }
3051 
3052   // First input register
3053   switch (Inst.getOpcode()) {
3054   case ARM::VST1q16:
3055   case ARM::VST1q32:
3056   case ARM::VST1q64:
3057   case ARM::VST1q8:
3058   case ARM::VST1q16wb_fixed:
3059   case ARM::VST1q16wb_register:
3060   case ARM::VST1q32wb_fixed:
3061   case ARM::VST1q32wb_register:
3062   case ARM::VST1q64wb_fixed:
3063   case ARM::VST1q64wb_register:
3064   case ARM::VST1q8wb_fixed:
3065   case ARM::VST1q8wb_register:
3066   case ARM::VST2d16:
3067   case ARM::VST2d32:
3068   case ARM::VST2d8:
3069   case ARM::VST2d16wb_fixed:
3070   case ARM::VST2d16wb_register:
3071   case ARM::VST2d32wb_fixed:
3072   case ARM::VST2d32wb_register:
3073   case ARM::VST2d8wb_fixed:
3074   case ARM::VST2d8wb_register:
3075     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
3076       return MCDisassembler::Fail;
3077     break;
3078   case ARM::VST2b16:
3079   case ARM::VST2b32:
3080   case ARM::VST2b8:
3081   case ARM::VST2b16wb_fixed:
3082   case ARM::VST2b16wb_register:
3083   case ARM::VST2b32wb_fixed:
3084   case ARM::VST2b32wb_register:
3085   case ARM::VST2b8wb_fixed:
3086   case ARM::VST2b8wb_register:
3087     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
3088       return MCDisassembler::Fail;
3089     break;
3090   default:
3091     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3092       return MCDisassembler::Fail;
3093   }
3094 
3095   // Second input register
3096   switch (Inst.getOpcode()) {
3097     case ARM::VST3d8:
3098     case ARM::VST3d16:
3099     case ARM::VST3d32:
3100     case ARM::VST3d8_UPD:
3101     case ARM::VST3d16_UPD:
3102     case ARM::VST3d32_UPD:
3103     case ARM::VST4d8:
3104     case ARM::VST4d16:
3105     case ARM::VST4d32:
3106     case ARM::VST4d8_UPD:
3107     case ARM::VST4d16_UPD:
3108     case ARM::VST4d32_UPD:
3109       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
3110         return MCDisassembler::Fail;
3111       break;
3112     case ARM::VST3q8:
3113     case ARM::VST3q16:
3114     case ARM::VST3q32:
3115     case ARM::VST3q8_UPD:
3116     case ARM::VST3q16_UPD:
3117     case ARM::VST3q32_UPD:
3118     case ARM::VST4q8:
3119     case ARM::VST4q16:
3120     case ARM::VST4q32:
3121     case ARM::VST4q8_UPD:
3122     case ARM::VST4q16_UPD:
3123     case ARM::VST4q32_UPD:
3124       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
3125         return MCDisassembler::Fail;
3126       break;
3127     default:
3128       break;
3129   }
3130 
3131   // Third input register
3132   switch (Inst.getOpcode()) {
3133     case ARM::VST3d8:
3134     case ARM::VST3d16:
3135     case ARM::VST3d32:
3136     case ARM::VST3d8_UPD:
3137     case ARM::VST3d16_UPD:
3138     case ARM::VST3d32_UPD:
3139     case ARM::VST4d8:
3140     case ARM::VST4d16:
3141     case ARM::VST4d32:
3142     case ARM::VST4d8_UPD:
3143     case ARM::VST4d16_UPD:
3144     case ARM::VST4d32_UPD:
3145       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
3146         return MCDisassembler::Fail;
3147       break;
3148     case ARM::VST3q8:
3149     case ARM::VST3q16:
3150     case ARM::VST3q32:
3151     case ARM::VST3q8_UPD:
3152     case ARM::VST3q16_UPD:
3153     case ARM::VST3q32_UPD:
3154     case ARM::VST4q8:
3155     case ARM::VST4q16:
3156     case ARM::VST4q32:
3157     case ARM::VST4q8_UPD:
3158     case ARM::VST4q16_UPD:
3159     case ARM::VST4q32_UPD:
3160       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
3161         return MCDisassembler::Fail;
3162       break;
3163     default:
3164       break;
3165   }
3166 
3167   // Fourth input register
3168   switch (Inst.getOpcode()) {
3169     case ARM::VST4d8:
3170     case ARM::VST4d16:
3171     case ARM::VST4d32:
3172     case ARM::VST4d8_UPD:
3173     case ARM::VST4d16_UPD:
3174     case ARM::VST4d32_UPD:
3175       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
3176         return MCDisassembler::Fail;
3177       break;
3178     case ARM::VST4q8:
3179     case ARM::VST4q16:
3180     case ARM::VST4q32:
3181     case ARM::VST4q8_UPD:
3182     case ARM::VST4q16_UPD:
3183     case ARM::VST4q32_UPD:
3184       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
3185         return MCDisassembler::Fail;
3186       break;
3187     default:
3188       break;
3189   }
3190 
3191   return S;
3192 }
3193 
3194 static DecodeStatus DecodeVLD1DupInstruction(MCInst &Inst, unsigned Insn,
3195                                     uint64_t Address, const void *Decoder) {
3196   DecodeStatus S = MCDisassembler::Success;
3197 
3198   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3199   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3200   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3201   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3202   unsigned align = fieldFromInstruction(Insn, 4, 1);
3203   unsigned size = fieldFromInstruction(Insn, 6, 2);
3204 
3205   if (size == 0 && align == 1)
3206     return MCDisassembler::Fail;
3207   align *= (1 << size);
3208 
3209   switch (Inst.getOpcode()) {
3210   case ARM::VLD1DUPq16: case ARM::VLD1DUPq32: case ARM::VLD1DUPq8:
3211   case ARM::VLD1DUPq16wb_fixed: case ARM::VLD1DUPq16wb_register:
3212   case ARM::VLD1DUPq32wb_fixed: case ARM::VLD1DUPq32wb_register:
3213   case ARM::VLD1DUPq8wb_fixed: case ARM::VLD1DUPq8wb_register:
3214     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
3215       return MCDisassembler::Fail;
3216     break;
3217   default:
3218     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3219       return MCDisassembler::Fail;
3220     break;
3221   }
3222   if (Rm != 0xF) {
3223     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3224       return MCDisassembler::Fail;
3225   }
3226 
3227   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3228     return MCDisassembler::Fail;
3229   Inst.addOperand(MCOperand::createImm(align));
3230 
3231   // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
3232   // variant encodes Rm == 0xf. Anything else is a register offset post-
3233   // increment and we need to add the register operand to the instruction.
3234   if (Rm != 0xD && Rm != 0xF &&
3235       !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3236     return MCDisassembler::Fail;
3237 
3238   return S;
3239 }
3240 
3241 static DecodeStatus DecodeVLD2DupInstruction(MCInst &Inst, unsigned Insn,
3242                                     uint64_t Address, const void *Decoder) {
3243   DecodeStatus S = MCDisassembler::Success;
3244 
3245   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3246   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3247   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3248   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3249   unsigned align = fieldFromInstruction(Insn, 4, 1);
3250   unsigned size = 1 << fieldFromInstruction(Insn, 6, 2);
3251   align *= 2*size;
3252 
3253   switch (Inst.getOpcode()) {
3254   case ARM::VLD2DUPd16: case ARM::VLD2DUPd32: case ARM::VLD2DUPd8:
3255   case ARM::VLD2DUPd16wb_fixed: case ARM::VLD2DUPd16wb_register:
3256   case ARM::VLD2DUPd32wb_fixed: case ARM::VLD2DUPd32wb_register:
3257   case ARM::VLD2DUPd8wb_fixed: case ARM::VLD2DUPd8wb_register:
3258     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
3259       return MCDisassembler::Fail;
3260     break;
3261   case ARM::VLD2DUPd16x2: case ARM::VLD2DUPd32x2: case ARM::VLD2DUPd8x2:
3262   case ARM::VLD2DUPd16x2wb_fixed: case ARM::VLD2DUPd16x2wb_register:
3263   case ARM::VLD2DUPd32x2wb_fixed: case ARM::VLD2DUPd32x2wb_register:
3264   case ARM::VLD2DUPd8x2wb_fixed: case ARM::VLD2DUPd8x2wb_register:
3265     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
3266       return MCDisassembler::Fail;
3267     break;
3268   default:
3269     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3270       return MCDisassembler::Fail;
3271     break;
3272   }
3273 
3274   if (Rm != 0xF)
3275     Inst.addOperand(MCOperand::createImm(0));
3276 
3277   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3278     return MCDisassembler::Fail;
3279   Inst.addOperand(MCOperand::createImm(align));
3280 
3281   if (Rm != 0xD && Rm != 0xF) {
3282     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3283       return MCDisassembler::Fail;
3284   }
3285 
3286   return S;
3287 }
3288 
3289 static DecodeStatus DecodeVLD3DupInstruction(MCInst &Inst, unsigned Insn,
3290                                     uint64_t Address, const void *Decoder) {
3291   DecodeStatus S = MCDisassembler::Success;
3292 
3293   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3294   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3295   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3296   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3297   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
3298 
3299   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3300     return MCDisassembler::Fail;
3301   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
3302     return MCDisassembler::Fail;
3303   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
3304     return MCDisassembler::Fail;
3305   if (Rm != 0xF) {
3306     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3307       return MCDisassembler::Fail;
3308   }
3309 
3310   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3311     return MCDisassembler::Fail;
3312   Inst.addOperand(MCOperand::createImm(0));
3313 
3314   if (Rm == 0xD)
3315     Inst.addOperand(MCOperand::createReg(0));
3316   else if (Rm != 0xF) {
3317     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3318       return MCDisassembler::Fail;
3319   }
3320 
3321   return S;
3322 }
3323 
3324 static DecodeStatus DecodeVLD4DupInstruction(MCInst &Inst, unsigned Insn,
3325                                     uint64_t Address, const void *Decoder) {
3326   DecodeStatus S = MCDisassembler::Success;
3327 
3328   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3329   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3330   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3331   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3332   unsigned size = fieldFromInstruction(Insn, 6, 2);
3333   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
3334   unsigned align = fieldFromInstruction(Insn, 4, 1);
3335 
3336   if (size == 0x3) {
3337     if (align == 0)
3338       return MCDisassembler::Fail;
3339     align = 16;
3340   } else {
3341     if (size == 2) {
3342       align *= 8;
3343     } else {
3344       size = 1 << size;
3345       align *= 4*size;
3346     }
3347   }
3348 
3349   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3350     return MCDisassembler::Fail;
3351   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
3352     return MCDisassembler::Fail;
3353   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
3354     return MCDisassembler::Fail;
3355   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
3356     return MCDisassembler::Fail;
3357   if (Rm != 0xF) {
3358     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3359       return MCDisassembler::Fail;
3360   }
3361 
3362   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3363     return MCDisassembler::Fail;
3364   Inst.addOperand(MCOperand::createImm(align));
3365 
3366   if (Rm == 0xD)
3367     Inst.addOperand(MCOperand::createReg(0));
3368   else if (Rm != 0xF) {
3369     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3370       return MCDisassembler::Fail;
3371   }
3372 
3373   return S;
3374 }
3375 
3376 static DecodeStatus
3377 DecodeNEONModImmInstruction(MCInst &Inst, unsigned Insn,
3378                             uint64_t Address, const void *Decoder) {
3379   DecodeStatus S = MCDisassembler::Success;
3380 
3381   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3382   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3383   unsigned imm = fieldFromInstruction(Insn, 0, 4);
3384   imm |= fieldFromInstruction(Insn, 16, 3) << 4;
3385   imm |= fieldFromInstruction(Insn, 24, 1) << 7;
3386   imm |= fieldFromInstruction(Insn, 8, 4) << 8;
3387   imm |= fieldFromInstruction(Insn, 5, 1) << 12;
3388   unsigned Q = fieldFromInstruction(Insn, 6, 1);
3389 
3390   if (Q) {
3391     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3392     return MCDisassembler::Fail;
3393   } else {
3394     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3395     return MCDisassembler::Fail;
3396   }
3397 
3398   Inst.addOperand(MCOperand::createImm(imm));
3399 
3400   switch (Inst.getOpcode()) {
3401     case ARM::VORRiv4i16:
3402     case ARM::VORRiv2i32:
3403     case ARM::VBICiv4i16:
3404     case ARM::VBICiv2i32:
3405       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3406         return MCDisassembler::Fail;
3407       break;
3408     case ARM::VORRiv8i16:
3409     case ARM::VORRiv4i32:
3410     case ARM::VBICiv8i16:
3411     case ARM::VBICiv4i32:
3412       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3413         return MCDisassembler::Fail;
3414       break;
3415     default:
3416       break;
3417   }
3418 
3419   return S;
3420 }
3421 
3422 static DecodeStatus DecodeVSHLMaxInstruction(MCInst &Inst, unsigned Insn,
3423                                         uint64_t Address, const void *Decoder) {
3424   DecodeStatus S = MCDisassembler::Success;
3425 
3426   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3427   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3428   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3429   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
3430   unsigned size = fieldFromInstruction(Insn, 18, 2);
3431 
3432   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3433     return MCDisassembler::Fail;
3434   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
3435     return MCDisassembler::Fail;
3436   Inst.addOperand(MCOperand::createImm(8 << size));
3437 
3438   return S;
3439 }
3440 
3441 static DecodeStatus DecodeShiftRight8Imm(MCInst &Inst, unsigned Val,
3442                                uint64_t Address, const void *Decoder) {
3443   Inst.addOperand(MCOperand::createImm(8 - Val));
3444   return MCDisassembler::Success;
3445 }
3446 
3447 static DecodeStatus DecodeShiftRight16Imm(MCInst &Inst, unsigned Val,
3448                                uint64_t Address, const void *Decoder) {
3449   Inst.addOperand(MCOperand::createImm(16 - Val));
3450   return MCDisassembler::Success;
3451 }
3452 
3453 static DecodeStatus DecodeShiftRight32Imm(MCInst &Inst, unsigned Val,
3454                                uint64_t Address, const void *Decoder) {
3455   Inst.addOperand(MCOperand::createImm(32 - Val));
3456   return MCDisassembler::Success;
3457 }
3458 
3459 static DecodeStatus DecodeShiftRight64Imm(MCInst &Inst, unsigned Val,
3460                                uint64_t Address, const void *Decoder) {
3461   Inst.addOperand(MCOperand::createImm(64 - Val));
3462   return MCDisassembler::Success;
3463 }
3464 
3465 static DecodeStatus DecodeTBLInstruction(MCInst &Inst, unsigned Insn,
3466                                uint64_t Address, const void *Decoder) {
3467   DecodeStatus S = MCDisassembler::Success;
3468 
3469   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3470   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3471   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3472   Rn |= fieldFromInstruction(Insn, 7, 1) << 4;
3473   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3474   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
3475   unsigned op = fieldFromInstruction(Insn, 6, 1);
3476 
3477   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3478     return MCDisassembler::Fail;
3479   if (op) {
3480     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3481     return MCDisassembler::Fail; // Writeback
3482   }
3483 
3484   switch (Inst.getOpcode()) {
3485   case ARM::VTBL2:
3486   case ARM::VTBX2:
3487     if (!Check(S, DecodeDPairRegisterClass(Inst, Rn, Address, Decoder)))
3488       return MCDisassembler::Fail;
3489     break;
3490   default:
3491     if (!Check(S, DecodeDPRRegisterClass(Inst, Rn, Address, Decoder)))
3492       return MCDisassembler::Fail;
3493   }
3494 
3495   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
3496     return MCDisassembler::Fail;
3497 
3498   return S;
3499 }
3500 
3501 static DecodeStatus DecodeThumbAddSpecialReg(MCInst &Inst, uint16_t Insn,
3502                                      uint64_t Address, const void *Decoder) {
3503   DecodeStatus S = MCDisassembler::Success;
3504 
3505   unsigned dst = fieldFromInstruction(Insn, 8, 3);
3506   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3507 
3508   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
3509     return MCDisassembler::Fail;
3510 
3511   switch(Inst.getOpcode()) {
3512     default:
3513       return MCDisassembler::Fail;
3514     case ARM::tADR:
3515       break; // tADR does not explicitly represent the PC as an operand.
3516     case ARM::tADDrSPi:
3517       Inst.addOperand(MCOperand::createReg(ARM::SP));
3518       break;
3519   }
3520 
3521   Inst.addOperand(MCOperand::createImm(imm));
3522   return S;
3523 }
3524 
3525 static DecodeStatus DecodeThumbBROperand(MCInst &Inst, unsigned Val,
3526                                  uint64_t Address, const void *Decoder) {
3527   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<12>(Val<<1) + 4,
3528                                 true, 2, Inst, Decoder))
3529     Inst.addOperand(MCOperand::createImm(SignExtend32<12>(Val << 1)));
3530   return MCDisassembler::Success;
3531 }
3532 
3533 static DecodeStatus DecodeT2BROperand(MCInst &Inst, unsigned Val,
3534                                  uint64_t Address, const void *Decoder) {
3535   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<21>(Val) + 4,
3536                                 true, 4, Inst, Decoder))
3537     Inst.addOperand(MCOperand::createImm(SignExtend32<21>(Val)));
3538   return MCDisassembler::Success;
3539 }
3540 
3541 static DecodeStatus DecodeThumbCmpBROperand(MCInst &Inst, unsigned Val,
3542                                  uint64_t Address, const void *Decoder) {
3543   if (!tryAddingSymbolicOperand(Address, Address + (Val<<1) + 4,
3544                                 true, 2, Inst, Decoder))
3545     Inst.addOperand(MCOperand::createImm(Val << 1));
3546   return MCDisassembler::Success;
3547 }
3548 
3549 static DecodeStatus DecodeThumbAddrModeRR(MCInst &Inst, unsigned Val,
3550                                  uint64_t Address, const void *Decoder) {
3551   DecodeStatus S = MCDisassembler::Success;
3552 
3553   unsigned Rn = fieldFromInstruction(Val, 0, 3);
3554   unsigned Rm = fieldFromInstruction(Val, 3, 3);
3555 
3556   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
3557     return MCDisassembler::Fail;
3558   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
3559     return MCDisassembler::Fail;
3560 
3561   return S;
3562 }
3563 
3564 static DecodeStatus DecodeThumbAddrModeIS(MCInst &Inst, unsigned Val,
3565                                   uint64_t Address, const void *Decoder) {
3566   DecodeStatus S = MCDisassembler::Success;
3567 
3568   unsigned Rn = fieldFromInstruction(Val, 0, 3);
3569   unsigned imm = fieldFromInstruction(Val, 3, 5);
3570 
3571   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
3572     return MCDisassembler::Fail;
3573   Inst.addOperand(MCOperand::createImm(imm));
3574 
3575   return S;
3576 }
3577 
3578 static DecodeStatus DecodeThumbAddrModePC(MCInst &Inst, unsigned Val,
3579                                   uint64_t Address, const void *Decoder) {
3580   unsigned imm = Val << 2;
3581 
3582   Inst.addOperand(MCOperand::createImm(imm));
3583   tryAddingPcLoadReferenceComment(Address, (Address & ~2u) + imm + 4, Decoder);
3584 
3585   return MCDisassembler::Success;
3586 }
3587 
3588 static DecodeStatus DecodeThumbAddrModeSP(MCInst &Inst, unsigned Val,
3589                                   uint64_t Address, const void *Decoder) {
3590   Inst.addOperand(MCOperand::createReg(ARM::SP));
3591   Inst.addOperand(MCOperand::createImm(Val));
3592 
3593   return MCDisassembler::Success;
3594 }
3595 
3596 static DecodeStatus DecodeT2AddrModeSOReg(MCInst &Inst, unsigned Val,
3597                                   uint64_t Address, const void *Decoder) {
3598   DecodeStatus S = MCDisassembler::Success;
3599 
3600   unsigned Rn = fieldFromInstruction(Val, 6, 4);
3601   unsigned Rm = fieldFromInstruction(Val, 2, 4);
3602   unsigned imm = fieldFromInstruction(Val, 0, 2);
3603 
3604   // Thumb stores cannot use PC as dest register.
3605   switch (Inst.getOpcode()) {
3606   case ARM::t2STRHs:
3607   case ARM::t2STRBs:
3608   case ARM::t2STRs:
3609     if (Rn == 15)
3610       return MCDisassembler::Fail;
3611     break;
3612   default:
3613     break;
3614   }
3615 
3616   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3617     return MCDisassembler::Fail;
3618   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
3619     return MCDisassembler::Fail;
3620   Inst.addOperand(MCOperand::createImm(imm));
3621 
3622   return S;
3623 }
3624 
3625 static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Insn,
3626                               uint64_t Address, const void *Decoder) {
3627   DecodeStatus S = MCDisassembler::Success;
3628 
3629   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3630   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3631 
3632   const FeatureBitset &featureBits =
3633     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3634 
3635   bool hasMP = featureBits[ARM::FeatureMP];
3636   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3637 
3638   if (Rn == 15) {
3639     switch (Inst.getOpcode()) {
3640     case ARM::t2LDRBs:
3641       Inst.setOpcode(ARM::t2LDRBpci);
3642       break;
3643     case ARM::t2LDRHs:
3644       Inst.setOpcode(ARM::t2LDRHpci);
3645       break;
3646     case ARM::t2LDRSHs:
3647       Inst.setOpcode(ARM::t2LDRSHpci);
3648       break;
3649     case ARM::t2LDRSBs:
3650       Inst.setOpcode(ARM::t2LDRSBpci);
3651       break;
3652     case ARM::t2LDRs:
3653       Inst.setOpcode(ARM::t2LDRpci);
3654       break;
3655     case ARM::t2PLDs:
3656       Inst.setOpcode(ARM::t2PLDpci);
3657       break;
3658     case ARM::t2PLIs:
3659       Inst.setOpcode(ARM::t2PLIpci);
3660       break;
3661     default:
3662       return MCDisassembler::Fail;
3663     }
3664 
3665     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3666   }
3667 
3668   if (Rt == 15) {
3669     switch (Inst.getOpcode()) {
3670     case ARM::t2LDRSHs:
3671       return MCDisassembler::Fail;
3672     case ARM::t2LDRHs:
3673       Inst.setOpcode(ARM::t2PLDWs);
3674       break;
3675     case ARM::t2LDRSBs:
3676       Inst.setOpcode(ARM::t2PLIs);
3677       break;
3678     default:
3679       break;
3680     }
3681   }
3682 
3683   switch (Inst.getOpcode()) {
3684     case ARM::t2PLDs:
3685       break;
3686     case ARM::t2PLIs:
3687       if (!hasV7Ops)
3688         return MCDisassembler::Fail;
3689       break;
3690     case ARM::t2PLDWs:
3691       if (!hasV7Ops || !hasMP)
3692         return MCDisassembler::Fail;
3693       break;
3694     default:
3695       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3696         return MCDisassembler::Fail;
3697   }
3698 
3699   unsigned addrmode = fieldFromInstruction(Insn, 4, 2);
3700   addrmode |= fieldFromInstruction(Insn, 0, 4) << 2;
3701   addrmode |= fieldFromInstruction(Insn, 16, 4) << 6;
3702   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
3703     return MCDisassembler::Fail;
3704 
3705   return S;
3706 }
3707 
3708 static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
3709                                 uint64_t Address, const void* Decoder) {
3710   DecodeStatus S = MCDisassembler::Success;
3711 
3712   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3713   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3714   unsigned U = fieldFromInstruction(Insn, 9, 1);
3715   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3716   imm |= (U << 8);
3717   imm |= (Rn << 9);
3718   unsigned add = fieldFromInstruction(Insn, 9, 1);
3719 
3720   const FeatureBitset &featureBits =
3721     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3722 
3723   bool hasMP = featureBits[ARM::FeatureMP];
3724   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3725 
3726   if (Rn == 15) {
3727     switch (Inst.getOpcode()) {
3728     case ARM::t2LDRi8:
3729       Inst.setOpcode(ARM::t2LDRpci);
3730       break;
3731     case ARM::t2LDRBi8:
3732       Inst.setOpcode(ARM::t2LDRBpci);
3733       break;
3734     case ARM::t2LDRSBi8:
3735       Inst.setOpcode(ARM::t2LDRSBpci);
3736       break;
3737     case ARM::t2LDRHi8:
3738       Inst.setOpcode(ARM::t2LDRHpci);
3739       break;
3740     case ARM::t2LDRSHi8:
3741       Inst.setOpcode(ARM::t2LDRSHpci);
3742       break;
3743     case ARM::t2PLDi8:
3744       Inst.setOpcode(ARM::t2PLDpci);
3745       break;
3746     case ARM::t2PLIi8:
3747       Inst.setOpcode(ARM::t2PLIpci);
3748       break;
3749     default:
3750       return MCDisassembler::Fail;
3751     }
3752     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3753   }
3754 
3755   if (Rt == 15) {
3756     switch (Inst.getOpcode()) {
3757     case ARM::t2LDRSHi8:
3758       return MCDisassembler::Fail;
3759     case ARM::t2LDRHi8:
3760       if (!add)
3761         Inst.setOpcode(ARM::t2PLDWi8);
3762       break;
3763     case ARM::t2LDRSBi8:
3764       Inst.setOpcode(ARM::t2PLIi8);
3765       break;
3766     default:
3767       break;
3768     }
3769   }
3770 
3771   switch (Inst.getOpcode()) {
3772   case ARM::t2PLDi8:
3773     break;
3774   case ARM::t2PLIi8:
3775     if (!hasV7Ops)
3776       return MCDisassembler::Fail;
3777     break;
3778   case ARM::t2PLDWi8:
3779       if (!hasV7Ops || !hasMP)
3780         return MCDisassembler::Fail;
3781       break;
3782   default:
3783     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3784       return MCDisassembler::Fail;
3785   }
3786 
3787   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
3788     return MCDisassembler::Fail;
3789   return S;
3790 }
3791 
3792 static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
3793                                 uint64_t Address, const void* Decoder) {
3794   DecodeStatus S = MCDisassembler::Success;
3795 
3796   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3797   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3798   unsigned imm = fieldFromInstruction(Insn, 0, 12);
3799   imm |= (Rn << 13);
3800 
3801   const FeatureBitset &featureBits =
3802     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3803 
3804   bool hasMP = featureBits[ARM::FeatureMP];
3805   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3806 
3807   if (Rn == 15) {
3808     switch (Inst.getOpcode()) {
3809     case ARM::t2LDRi12:
3810       Inst.setOpcode(ARM::t2LDRpci);
3811       break;
3812     case ARM::t2LDRHi12:
3813       Inst.setOpcode(ARM::t2LDRHpci);
3814       break;
3815     case ARM::t2LDRSHi12:
3816       Inst.setOpcode(ARM::t2LDRSHpci);
3817       break;
3818     case ARM::t2LDRBi12:
3819       Inst.setOpcode(ARM::t2LDRBpci);
3820       break;
3821     case ARM::t2LDRSBi12:
3822       Inst.setOpcode(ARM::t2LDRSBpci);
3823       break;
3824     case ARM::t2PLDi12:
3825       Inst.setOpcode(ARM::t2PLDpci);
3826       break;
3827     case ARM::t2PLIi12:
3828       Inst.setOpcode(ARM::t2PLIpci);
3829       break;
3830     default:
3831       return MCDisassembler::Fail;
3832     }
3833     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3834   }
3835 
3836   if (Rt == 15) {
3837     switch (Inst.getOpcode()) {
3838     case ARM::t2LDRSHi12:
3839       return MCDisassembler::Fail;
3840     case ARM::t2LDRHi12:
3841       Inst.setOpcode(ARM::t2PLDWi12);
3842       break;
3843     case ARM::t2LDRSBi12:
3844       Inst.setOpcode(ARM::t2PLIi12);
3845       break;
3846     default:
3847       break;
3848     }
3849   }
3850 
3851   switch (Inst.getOpcode()) {
3852   case ARM::t2PLDi12:
3853     break;
3854   case ARM::t2PLIi12:
3855     if (!hasV7Ops)
3856       return MCDisassembler::Fail;
3857     break;
3858   case ARM::t2PLDWi12:
3859       if (!hasV7Ops || !hasMP)
3860         return MCDisassembler::Fail;
3861       break;
3862   default:
3863     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3864       return MCDisassembler::Fail;
3865   }
3866 
3867   if (!Check(S, DecodeT2AddrModeImm12(Inst, imm, Address, Decoder)))
3868     return MCDisassembler::Fail;
3869   return S;
3870 }
3871 
3872 static DecodeStatus DecodeT2LoadT(MCInst &Inst, unsigned Insn,
3873                                 uint64_t Address, const void* Decoder) {
3874   DecodeStatus S = MCDisassembler::Success;
3875 
3876   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3877   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3878   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3879   imm |= (Rn << 9);
3880 
3881   if (Rn == 15) {
3882     switch (Inst.getOpcode()) {
3883     case ARM::t2LDRT:
3884       Inst.setOpcode(ARM::t2LDRpci);
3885       break;
3886     case ARM::t2LDRBT:
3887       Inst.setOpcode(ARM::t2LDRBpci);
3888       break;
3889     case ARM::t2LDRHT:
3890       Inst.setOpcode(ARM::t2LDRHpci);
3891       break;
3892     case ARM::t2LDRSBT:
3893       Inst.setOpcode(ARM::t2LDRSBpci);
3894       break;
3895     case ARM::t2LDRSHT:
3896       Inst.setOpcode(ARM::t2LDRSHpci);
3897       break;
3898     default:
3899       return MCDisassembler::Fail;
3900     }
3901     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3902   }
3903 
3904   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3905     return MCDisassembler::Fail;
3906   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
3907     return MCDisassembler::Fail;
3908   return S;
3909 }
3910 
3911 static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
3912                                 uint64_t Address, const void* Decoder) {
3913   DecodeStatus S = MCDisassembler::Success;
3914 
3915   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3916   unsigned U = fieldFromInstruction(Insn, 23, 1);
3917   int imm = fieldFromInstruction(Insn, 0, 12);
3918 
3919   const FeatureBitset &featureBits =
3920     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3921 
3922   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3923 
3924   if (Rt == 15) {
3925     switch (Inst.getOpcode()) {
3926       case ARM::t2LDRBpci:
3927       case ARM::t2LDRHpci:
3928         Inst.setOpcode(ARM::t2PLDpci);
3929         break;
3930       case ARM::t2LDRSBpci:
3931         Inst.setOpcode(ARM::t2PLIpci);
3932         break;
3933       case ARM::t2LDRSHpci:
3934         return MCDisassembler::Fail;
3935       default:
3936         break;
3937     }
3938   }
3939 
3940   switch(Inst.getOpcode()) {
3941   case ARM::t2PLDpci:
3942     break;
3943   case ARM::t2PLIpci:
3944     if (!hasV7Ops)
3945       return MCDisassembler::Fail;
3946     break;
3947   default:
3948     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3949       return MCDisassembler::Fail;
3950   }
3951 
3952   if (!U) {
3953     // Special case for #-0.
3954     if (imm == 0)
3955       imm = INT32_MIN;
3956     else
3957       imm = -imm;
3958   }
3959   Inst.addOperand(MCOperand::createImm(imm));
3960 
3961   return S;
3962 }
3963 
3964 static DecodeStatus DecodeT2Imm8S4(MCInst &Inst, unsigned Val,
3965                            uint64_t Address, const void *Decoder) {
3966   if (Val == 0)
3967     Inst.addOperand(MCOperand::createImm(INT32_MIN));
3968   else {
3969     int imm = Val & 0xFF;
3970 
3971     if (!(Val & 0x100)) imm *= -1;
3972     Inst.addOperand(MCOperand::createImm(imm * 4));
3973   }
3974 
3975   return MCDisassembler::Success;
3976 }
3977 
3978 static DecodeStatus DecodeT2Imm7S4(MCInst &Inst, unsigned Val, uint64_t Address,
3979                                    const void *Decoder) {
3980   if (Val == 0)
3981     Inst.addOperand(MCOperand::createImm(INT32_MIN));
3982   else {
3983     int imm = Val & 0x7F;
3984 
3985     if (!(Val & 0x80))
3986       imm *= -1;
3987     Inst.addOperand(MCOperand::createImm(imm * 4));
3988   }
3989 
3990   return MCDisassembler::Success;
3991 }
3992 
3993 static DecodeStatus DecodeT2AddrModeImm8s4(MCInst &Inst, unsigned Val,
3994                                    uint64_t Address, const void *Decoder) {
3995   DecodeStatus S = MCDisassembler::Success;
3996 
3997   unsigned Rn = fieldFromInstruction(Val, 9, 4);
3998   unsigned imm = fieldFromInstruction(Val, 0, 9);
3999 
4000   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4001     return MCDisassembler::Fail;
4002   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
4003     return MCDisassembler::Fail;
4004 
4005   return S;
4006 }
4007 
4008 static DecodeStatus DecodeT2AddrModeImm7s4(MCInst &Inst, unsigned Val,
4009                                            uint64_t Address,
4010                                            const void *Decoder) {
4011   DecodeStatus S = MCDisassembler::Success;
4012 
4013   unsigned Rn = fieldFromInstruction(Val, 8, 4);
4014   unsigned imm = fieldFromInstruction(Val, 0, 8);
4015 
4016   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
4017     return MCDisassembler::Fail;
4018   if (!Check(S, DecodeT2Imm7S4(Inst, imm, Address, Decoder)))
4019     return MCDisassembler::Fail;
4020 
4021   return S;
4022 }
4023 
4024 static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst &Inst,unsigned Val,
4025                                    uint64_t Address, const void *Decoder) {
4026   DecodeStatus S = MCDisassembler::Success;
4027 
4028   unsigned Rn = fieldFromInstruction(Val, 8, 4);
4029   unsigned imm = fieldFromInstruction(Val, 0, 8);
4030 
4031   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
4032     return MCDisassembler::Fail;
4033 
4034   Inst.addOperand(MCOperand::createImm(imm));
4035 
4036   return S;
4037 }
4038 
4039 static DecodeStatus DecodeT2Imm8(MCInst &Inst, unsigned Val,
4040                          uint64_t Address, const void *Decoder) {
4041   int imm = Val & 0xFF;
4042   if (Val == 0)
4043     imm = INT32_MIN;
4044   else if (!(Val & 0x100))
4045     imm *= -1;
4046   Inst.addOperand(MCOperand::createImm(imm));
4047 
4048   return MCDisassembler::Success;
4049 }
4050 
4051 static DecodeStatus DecodeT2AddrModeImm8(MCInst &Inst, unsigned Val,
4052                                  uint64_t Address, const void *Decoder) {
4053   DecodeStatus S = MCDisassembler::Success;
4054 
4055   unsigned Rn = fieldFromInstruction(Val, 9, 4);
4056   unsigned imm = fieldFromInstruction(Val, 0, 9);
4057 
4058   // Thumb stores cannot use PC as dest register.
4059   switch (Inst.getOpcode()) {
4060   case ARM::t2STRT:
4061   case ARM::t2STRBT:
4062   case ARM::t2STRHT:
4063   case ARM::t2STRi8:
4064   case ARM::t2STRHi8:
4065   case ARM::t2STRBi8:
4066     if (Rn == 15)
4067       return MCDisassembler::Fail;
4068     break;
4069   default:
4070     break;
4071   }
4072 
4073   // Some instructions always use an additive offset.
4074   switch (Inst.getOpcode()) {
4075     case ARM::t2LDRT:
4076     case ARM::t2LDRBT:
4077     case ARM::t2LDRHT:
4078     case ARM::t2LDRSBT:
4079     case ARM::t2LDRSHT:
4080     case ARM::t2STRT:
4081     case ARM::t2STRBT:
4082     case ARM::t2STRHT:
4083       imm |= 0x100;
4084       break;
4085     default:
4086       break;
4087   }
4088 
4089   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4090     return MCDisassembler::Fail;
4091   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
4092     return MCDisassembler::Fail;
4093 
4094   return S;
4095 }
4096 
4097 static DecodeStatus DecodeT2LdStPre(MCInst &Inst, unsigned Insn,
4098                                     uint64_t Address, const void *Decoder) {
4099   DecodeStatus S = MCDisassembler::Success;
4100 
4101   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4102   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4103   unsigned addr = fieldFromInstruction(Insn, 0, 8);
4104   addr |= fieldFromInstruction(Insn, 9, 1) << 8;
4105   addr |= Rn << 9;
4106   unsigned load = fieldFromInstruction(Insn, 20, 1);
4107 
4108   if (Rn == 15) {
4109     switch (Inst.getOpcode()) {
4110     case ARM::t2LDR_PRE:
4111     case ARM::t2LDR_POST:
4112       Inst.setOpcode(ARM::t2LDRpci);
4113       break;
4114     case ARM::t2LDRB_PRE:
4115     case ARM::t2LDRB_POST:
4116       Inst.setOpcode(ARM::t2LDRBpci);
4117       break;
4118     case ARM::t2LDRH_PRE:
4119     case ARM::t2LDRH_POST:
4120       Inst.setOpcode(ARM::t2LDRHpci);
4121       break;
4122     case ARM::t2LDRSB_PRE:
4123     case ARM::t2LDRSB_POST:
4124       if (Rt == 15)
4125         Inst.setOpcode(ARM::t2PLIpci);
4126       else
4127         Inst.setOpcode(ARM::t2LDRSBpci);
4128       break;
4129     case ARM::t2LDRSH_PRE:
4130     case ARM::t2LDRSH_POST:
4131       Inst.setOpcode(ARM::t2LDRSHpci);
4132       break;
4133     default:
4134       return MCDisassembler::Fail;
4135     }
4136     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
4137   }
4138 
4139   if (!load) {
4140     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4141       return MCDisassembler::Fail;
4142   }
4143 
4144   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4145     return MCDisassembler::Fail;
4146 
4147   if (load) {
4148     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4149       return MCDisassembler::Fail;
4150   }
4151 
4152   if (!Check(S, DecodeT2AddrModeImm8(Inst, addr, Address, Decoder)))
4153     return MCDisassembler::Fail;
4154 
4155   return S;
4156 }
4157 
4158 static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
4159                                   uint64_t Address, const void *Decoder) {
4160   DecodeStatus S = MCDisassembler::Success;
4161 
4162   unsigned Rn = fieldFromInstruction(Val, 13, 4);
4163   unsigned imm = fieldFromInstruction(Val, 0, 12);
4164 
4165   // Thumb stores cannot use PC as dest register.
4166   switch (Inst.getOpcode()) {
4167   case ARM::t2STRi12:
4168   case ARM::t2STRBi12:
4169   case ARM::t2STRHi12:
4170     if (Rn == 15)
4171       return MCDisassembler::Fail;
4172     break;
4173   default:
4174     break;
4175   }
4176 
4177   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4178     return MCDisassembler::Fail;
4179   Inst.addOperand(MCOperand::createImm(imm));
4180 
4181   return S;
4182 }
4183 
4184 static DecodeStatus DecodeThumbAddSPImm(MCInst &Inst, uint16_t Insn,
4185                                 uint64_t Address, const void *Decoder) {
4186   unsigned imm = fieldFromInstruction(Insn, 0, 7);
4187 
4188   Inst.addOperand(MCOperand::createReg(ARM::SP));
4189   Inst.addOperand(MCOperand::createReg(ARM::SP));
4190   Inst.addOperand(MCOperand::createImm(imm));
4191 
4192   return MCDisassembler::Success;
4193 }
4194 
4195 static DecodeStatus DecodeThumbAddSPReg(MCInst &Inst, uint16_t Insn,
4196                                 uint64_t Address, const void *Decoder) {
4197   DecodeStatus S = MCDisassembler::Success;
4198 
4199   if (Inst.getOpcode() == ARM::tADDrSP) {
4200     unsigned Rdm = fieldFromInstruction(Insn, 0, 3);
4201     Rdm |= fieldFromInstruction(Insn, 7, 1) << 3;
4202 
4203     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
4204     return MCDisassembler::Fail;
4205     Inst.addOperand(MCOperand::createReg(ARM::SP));
4206     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
4207     return MCDisassembler::Fail;
4208   } else if (Inst.getOpcode() == ARM::tADDspr) {
4209     unsigned Rm = fieldFromInstruction(Insn, 3, 4);
4210 
4211     Inst.addOperand(MCOperand::createReg(ARM::SP));
4212     Inst.addOperand(MCOperand::createReg(ARM::SP));
4213     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4214     return MCDisassembler::Fail;
4215   }
4216 
4217   return S;
4218 }
4219 
4220 static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
4221                            uint64_t Address, const void *Decoder) {
4222   unsigned imod = fieldFromInstruction(Insn, 4, 1) | 0x2;
4223   unsigned flags = fieldFromInstruction(Insn, 0, 3);
4224 
4225   Inst.addOperand(MCOperand::createImm(imod));
4226   Inst.addOperand(MCOperand::createImm(flags));
4227 
4228   return MCDisassembler::Success;
4229 }
4230 
4231 static DecodeStatus DecodePostIdxReg(MCInst &Inst, unsigned Insn,
4232                              uint64_t Address, const void *Decoder) {
4233   DecodeStatus S = MCDisassembler::Success;
4234   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4235   unsigned add = fieldFromInstruction(Insn, 4, 1);
4236 
4237   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
4238     return MCDisassembler::Fail;
4239   Inst.addOperand(MCOperand::createImm(add));
4240 
4241   return S;
4242 }
4243 
4244 static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Val,
4245                                  uint64_t Address, const void *Decoder) {
4246   // Val is passed in as S:J1:J2:imm10H:imm10L:'0'
4247   // Note only one trailing zero not two.  Also the J1 and J2 values are from
4248   // the encoded instruction.  So here change to I1 and I2 values via:
4249   // I1 = NOT(J1 EOR S);
4250   // I2 = NOT(J2 EOR S);
4251   // and build the imm32 with two trailing zeros as documented:
4252   // imm32 = SignExtend(S:I1:I2:imm10H:imm10L:'00', 32);
4253   unsigned S = (Val >> 23) & 1;
4254   unsigned J1 = (Val >> 22) & 1;
4255   unsigned J2 = (Val >> 21) & 1;
4256   unsigned I1 = !(J1 ^ S);
4257   unsigned I2 = !(J2 ^ S);
4258   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
4259   int imm32 = SignExtend32<25>(tmp << 1);
4260 
4261   if (!tryAddingSymbolicOperand(Address,
4262                                 (Address & ~2u) + imm32 + 4,
4263                                 true, 4, Inst, Decoder))
4264     Inst.addOperand(MCOperand::createImm(imm32));
4265   return MCDisassembler::Success;
4266 }
4267 
4268 static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Val,
4269                               uint64_t Address, const void *Decoder) {
4270   if (Val == 0xA || Val == 0xB)
4271     return MCDisassembler::Fail;
4272 
4273   const FeatureBitset &featureBits =
4274     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
4275 
4276   if (featureBits[ARM::HasV8Ops] && !(Val == 14 || Val == 15))
4277     return MCDisassembler::Fail;
4278 
4279   // For Armv8.1-M Mainline coprocessors matching 100x,101x or 111x should
4280   // decode as VFP/MVE instructions.
4281   if (featureBits[ARM::HasV8_1MMainlineOps] &&
4282       ((Val & 0xE) == 0x8 || (Val & 0xE) == 0xA ||
4283        (Val & 0xE) == 0xE))
4284     return MCDisassembler::Fail;
4285 
4286   Inst.addOperand(MCOperand::createImm(Val));
4287   return MCDisassembler::Success;
4288 }
4289 
4290 static DecodeStatus
4291 DecodeThumbTableBranch(MCInst &Inst, unsigned Insn,
4292                        uint64_t Address, const void *Decoder) {
4293   DecodeStatus S = MCDisassembler::Success;
4294 
4295   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4296   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4297 
4298   if (Rn == ARM::SP) S = MCDisassembler::SoftFail;
4299   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4300     return MCDisassembler::Fail;
4301   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
4302     return MCDisassembler::Fail;
4303   return S;
4304 }
4305 
4306 static DecodeStatus
4307 DecodeThumb2BCCInstruction(MCInst &Inst, unsigned Insn,
4308                            uint64_t Address, const void *Decoder) {
4309   DecodeStatus S = MCDisassembler::Success;
4310 
4311   unsigned pred = fieldFromInstruction(Insn, 22, 4);
4312   if (pred == 0xE || pred == 0xF) {
4313     unsigned opc = fieldFromInstruction(Insn, 4, 28);
4314     switch (opc) {
4315       default:
4316         return MCDisassembler::Fail;
4317       case 0xf3bf8f4:
4318         Inst.setOpcode(ARM::t2DSB);
4319         break;
4320       case 0xf3bf8f5:
4321         Inst.setOpcode(ARM::t2DMB);
4322         break;
4323       case 0xf3bf8f6:
4324         Inst.setOpcode(ARM::t2ISB);
4325         break;
4326     }
4327 
4328     unsigned imm = fieldFromInstruction(Insn, 0, 4);
4329     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
4330   }
4331 
4332   unsigned brtarget = fieldFromInstruction(Insn, 0, 11) << 1;
4333   brtarget |= fieldFromInstruction(Insn, 11, 1) << 19;
4334   brtarget |= fieldFromInstruction(Insn, 13, 1) << 18;
4335   brtarget |= fieldFromInstruction(Insn, 16, 6) << 12;
4336   brtarget |= fieldFromInstruction(Insn, 26, 1) << 20;
4337 
4338   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
4339     return MCDisassembler::Fail;
4340   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4341     return MCDisassembler::Fail;
4342 
4343   return S;
4344 }
4345 
4346 // Decode a shifted immediate operand.  These basically consist
4347 // of an 8-bit value, and a 4-bit directive that specifies either
4348 // a splat operation or a rotation.
4349 static DecodeStatus DecodeT2SOImm(MCInst &Inst, unsigned Val,
4350                           uint64_t Address, const void *Decoder) {
4351   unsigned ctrl = fieldFromInstruction(Val, 10, 2);
4352   if (ctrl == 0) {
4353     unsigned byte = fieldFromInstruction(Val, 8, 2);
4354     unsigned imm = fieldFromInstruction(Val, 0, 8);
4355     switch (byte) {
4356       case 0:
4357         Inst.addOperand(MCOperand::createImm(imm));
4358         break;
4359       case 1:
4360         Inst.addOperand(MCOperand::createImm((imm << 16) | imm));
4361         break;
4362       case 2:
4363         Inst.addOperand(MCOperand::createImm((imm << 24) | (imm << 8)));
4364         break;
4365       case 3:
4366         Inst.addOperand(MCOperand::createImm((imm << 24) | (imm << 16) |
4367                                              (imm << 8)  |  imm));
4368         break;
4369     }
4370   } else {
4371     unsigned unrot = fieldFromInstruction(Val, 0, 7) | 0x80;
4372     unsigned rot = fieldFromInstruction(Val, 7, 5);
4373     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
4374     Inst.addOperand(MCOperand::createImm(imm));
4375   }
4376 
4377   return MCDisassembler::Success;
4378 }
4379 
4380 static DecodeStatus
4381 DecodeThumbBCCTargetOperand(MCInst &Inst, unsigned Val,
4382                             uint64_t Address, const void *Decoder) {
4383   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<9>(Val<<1) + 4,
4384                                 true, 2, Inst, Decoder))
4385     Inst.addOperand(MCOperand::createImm(SignExtend32<9>(Val << 1)));
4386   return MCDisassembler::Success;
4387 }
4388 
4389 static DecodeStatus DecodeThumbBLTargetOperand(MCInst &Inst, unsigned Val,
4390                                                uint64_t Address,
4391                                                const void *Decoder) {
4392   // Val is passed in as S:J1:J2:imm10:imm11
4393   // Note no trailing zero after imm11.  Also the J1 and J2 values are from
4394   // the encoded instruction.  So here change to I1 and I2 values via:
4395   // I1 = NOT(J1 EOR S);
4396   // I2 = NOT(J2 EOR S);
4397   // and build the imm32 with one trailing zero as documented:
4398   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
4399   unsigned S = (Val >> 23) & 1;
4400   unsigned J1 = (Val >> 22) & 1;
4401   unsigned J2 = (Val >> 21) & 1;
4402   unsigned I1 = !(J1 ^ S);
4403   unsigned I2 = !(J2 ^ S);
4404   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
4405   int imm32 = SignExtend32<25>(tmp << 1);
4406 
4407   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
4408                                 true, 4, Inst, Decoder))
4409     Inst.addOperand(MCOperand::createImm(imm32));
4410   return MCDisassembler::Success;
4411 }
4412 
4413 static DecodeStatus DecodeMemBarrierOption(MCInst &Inst, unsigned Val,
4414                                    uint64_t Address, const void *Decoder) {
4415   if (Val & ~0xf)
4416     return MCDisassembler::Fail;
4417 
4418   Inst.addOperand(MCOperand::createImm(Val));
4419   return MCDisassembler::Success;
4420 }
4421 
4422 static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Val,
4423                                         uint64_t Address, const void *Decoder) {
4424   if (Val & ~0xf)
4425     return MCDisassembler::Fail;
4426 
4427   Inst.addOperand(MCOperand::createImm(Val));
4428   return MCDisassembler::Success;
4429 }
4430 
4431 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val,
4432                           uint64_t Address, const void *Decoder) {
4433   DecodeStatus S = MCDisassembler::Success;
4434   const FeatureBitset &FeatureBits =
4435     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
4436 
4437   if (FeatureBits[ARM::FeatureMClass]) {
4438     unsigned ValLow = Val & 0xff;
4439 
4440     // Validate the SYSm value first.
4441     switch (ValLow) {
4442     case  0: // apsr
4443     case  1: // iapsr
4444     case  2: // eapsr
4445     case  3: // xpsr
4446     case  5: // ipsr
4447     case  6: // epsr
4448     case  7: // iepsr
4449     case  8: // msp
4450     case  9: // psp
4451     case 16: // primask
4452     case 20: // control
4453       break;
4454     case 17: // basepri
4455     case 18: // basepri_max
4456     case 19: // faultmask
4457       if (!(FeatureBits[ARM::HasV7Ops]))
4458         // Values basepri, basepri_max and faultmask are only valid for v7m.
4459         return MCDisassembler::Fail;
4460       break;
4461     case 0x8a: // msplim_ns
4462     case 0x8b: // psplim_ns
4463     case 0x91: // basepri_ns
4464     case 0x93: // faultmask_ns
4465       if (!(FeatureBits[ARM::HasV8MMainlineOps]))
4466         return MCDisassembler::Fail;
4467       LLVM_FALLTHROUGH;
4468     case 10:   // msplim
4469     case 11:   // psplim
4470     case 0x88: // msp_ns
4471     case 0x89: // psp_ns
4472     case 0x90: // primask_ns
4473     case 0x94: // control_ns
4474     case 0x98: // sp_ns
4475       if (!(FeatureBits[ARM::Feature8MSecExt]))
4476         return MCDisassembler::Fail;
4477       break;
4478     default:
4479       // Architecturally defined as unpredictable
4480       S = MCDisassembler::SoftFail;
4481       break;
4482     }
4483 
4484     if (Inst.getOpcode() == ARM::t2MSR_M) {
4485       unsigned Mask = fieldFromInstruction(Val, 10, 2);
4486       if (!(FeatureBits[ARM::HasV7Ops])) {
4487         // The ARMv6-M MSR bits {11-10} can be only 0b10, other values are
4488         // unpredictable.
4489         if (Mask != 2)
4490           S = MCDisassembler::SoftFail;
4491       }
4492       else {
4493         // The ARMv7-M architecture stores an additional 2-bit mask value in
4494         // MSR bits {11-10}. The mask is used only with apsr, iapsr, eapsr and
4495         // xpsr, it has to be 0b10 in other cases. Bit mask{1} indicates if
4496         // the NZCVQ bits should be moved by the instruction. Bit mask{0}
4497         // indicates the move for the GE{3:0} bits, the mask{0} bit can be set
4498         // only if the processor includes the DSP extension.
4499         if (Mask == 0 || (Mask != 2 && ValLow > 3) ||
4500             (!(FeatureBits[ARM::FeatureDSP]) && (Mask & 1)))
4501           S = MCDisassembler::SoftFail;
4502       }
4503     }
4504   } else {
4505     // A/R class
4506     if (Val == 0)
4507       return MCDisassembler::Fail;
4508   }
4509   Inst.addOperand(MCOperand::createImm(Val));
4510   return S;
4511 }
4512 
4513 static DecodeStatus DecodeBankedReg(MCInst &Inst, unsigned Val,
4514                                     uint64_t Address, const void *Decoder) {
4515   unsigned R = fieldFromInstruction(Val, 5, 1);
4516   unsigned SysM = fieldFromInstruction(Val, 0, 5);
4517 
4518   // The table of encodings for these banked registers comes from B9.2.3 of the
4519   // ARM ARM. There are patterns, but nothing regular enough to make this logic
4520   // neater. So by fiat, these values are UNPREDICTABLE:
4521   if (!ARMBankedReg::lookupBankedRegByEncoding((R << 5) | SysM))
4522     return MCDisassembler::Fail;
4523 
4524   Inst.addOperand(MCOperand::createImm(Val));
4525   return MCDisassembler::Success;
4526 }
4527 
4528 static DecodeStatus DecodeDoubleRegLoad(MCInst &Inst, unsigned Insn,
4529                                         uint64_t Address, const void *Decoder) {
4530   DecodeStatus S = MCDisassembler::Success;
4531 
4532   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4533   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4534   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4535 
4536   if (Rn == 0xF)
4537     S = MCDisassembler::SoftFail;
4538 
4539   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
4540     return MCDisassembler::Fail;
4541   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4542     return MCDisassembler::Fail;
4543   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4544     return MCDisassembler::Fail;
4545 
4546   return S;
4547 }
4548 
4549 static DecodeStatus DecodeDoubleRegStore(MCInst &Inst, unsigned Insn,
4550                                          uint64_t Address,
4551                                          const void *Decoder) {
4552   DecodeStatus S = MCDisassembler::Success;
4553 
4554   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4555   unsigned Rt = fieldFromInstruction(Insn, 0, 4);
4556   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4557   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4558 
4559   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
4560     return MCDisassembler::Fail;
4561 
4562   if (Rn == 0xF || Rd == Rn || Rd == Rt || Rd == Rt+1)
4563     S = MCDisassembler::SoftFail;
4564 
4565   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
4566     return MCDisassembler::Fail;
4567   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4568     return MCDisassembler::Fail;
4569   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4570     return MCDisassembler::Fail;
4571 
4572   return S;
4573 }
4574 
4575 static DecodeStatus DecodeLDRPreImm(MCInst &Inst, unsigned Insn,
4576                             uint64_t Address, const void *Decoder) {
4577   DecodeStatus S = MCDisassembler::Success;
4578 
4579   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4580   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4581   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4582   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4583   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4584   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4585 
4586   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4587 
4588   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4589     return MCDisassembler::Fail;
4590   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4591     return MCDisassembler::Fail;
4592   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
4593     return MCDisassembler::Fail;
4594   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4595     return MCDisassembler::Fail;
4596 
4597   return S;
4598 }
4599 
4600 static DecodeStatus DecodeLDRPreReg(MCInst &Inst, unsigned Insn,
4601                             uint64_t Address, const void *Decoder) {
4602   DecodeStatus S = MCDisassembler::Success;
4603 
4604   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4605   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4606   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4607   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4608   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4609   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4610   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4611 
4612   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4613   if (Rm == 0xF) S = MCDisassembler::SoftFail;
4614 
4615   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4616     return MCDisassembler::Fail;
4617   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4618     return MCDisassembler::Fail;
4619   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
4620     return MCDisassembler::Fail;
4621   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4622     return MCDisassembler::Fail;
4623 
4624   return S;
4625 }
4626 
4627 static DecodeStatus DecodeSTRPreImm(MCInst &Inst, unsigned Insn,
4628                             uint64_t Address, const void *Decoder) {
4629   DecodeStatus S = MCDisassembler::Success;
4630 
4631   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4632   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4633   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4634   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4635   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4636   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4637 
4638   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4639 
4640   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4641     return MCDisassembler::Fail;
4642   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4643     return MCDisassembler::Fail;
4644   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
4645     return MCDisassembler::Fail;
4646   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4647     return MCDisassembler::Fail;
4648 
4649   return S;
4650 }
4651 
4652 static DecodeStatus DecodeSTRPreReg(MCInst &Inst, unsigned Insn,
4653                             uint64_t Address, const void *Decoder) {
4654   DecodeStatus S = MCDisassembler::Success;
4655 
4656   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4657   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4658   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4659   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4660   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4661   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4662 
4663   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4664 
4665   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4666     return MCDisassembler::Fail;
4667   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4668     return MCDisassembler::Fail;
4669   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
4670     return MCDisassembler::Fail;
4671   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4672     return MCDisassembler::Fail;
4673 
4674   return S;
4675 }
4676 
4677 static DecodeStatus DecodeVLD1LN(MCInst &Inst, unsigned Insn,
4678                          uint64_t Address, const void *Decoder) {
4679   DecodeStatus S = MCDisassembler::Success;
4680 
4681   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4682   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4683   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4684   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4685   unsigned size = fieldFromInstruction(Insn, 10, 2);
4686 
4687   unsigned align = 0;
4688   unsigned index = 0;
4689   switch (size) {
4690     default:
4691       return MCDisassembler::Fail;
4692     case 0:
4693       if (fieldFromInstruction(Insn, 4, 1))
4694         return MCDisassembler::Fail; // UNDEFINED
4695       index = fieldFromInstruction(Insn, 5, 3);
4696       break;
4697     case 1:
4698       if (fieldFromInstruction(Insn, 5, 1))
4699         return MCDisassembler::Fail; // UNDEFINED
4700       index = fieldFromInstruction(Insn, 6, 2);
4701       if (fieldFromInstruction(Insn, 4, 1))
4702         align = 2;
4703       break;
4704     case 2:
4705       if (fieldFromInstruction(Insn, 6, 1))
4706         return MCDisassembler::Fail; // UNDEFINED
4707       index = fieldFromInstruction(Insn, 7, 1);
4708 
4709       switch (fieldFromInstruction(Insn, 4, 2)) {
4710         case 0 :
4711           align = 0; break;
4712         case 3:
4713           align = 4; break;
4714         default:
4715           return MCDisassembler::Fail;
4716       }
4717       break;
4718   }
4719 
4720   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4721     return MCDisassembler::Fail;
4722   if (Rm != 0xF) { // Writeback
4723     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4724       return MCDisassembler::Fail;
4725   }
4726   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4727     return MCDisassembler::Fail;
4728   Inst.addOperand(MCOperand::createImm(align));
4729   if (Rm != 0xF) {
4730     if (Rm != 0xD) {
4731       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4732         return MCDisassembler::Fail;
4733     } else
4734       Inst.addOperand(MCOperand::createReg(0));
4735   }
4736 
4737   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4738     return MCDisassembler::Fail;
4739   Inst.addOperand(MCOperand::createImm(index));
4740 
4741   return S;
4742 }
4743 
4744 static DecodeStatus DecodeVST1LN(MCInst &Inst, unsigned Insn,
4745                          uint64_t Address, const void *Decoder) {
4746   DecodeStatus S = MCDisassembler::Success;
4747 
4748   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4749   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4750   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4751   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4752   unsigned size = fieldFromInstruction(Insn, 10, 2);
4753 
4754   unsigned align = 0;
4755   unsigned index = 0;
4756   switch (size) {
4757     default:
4758       return MCDisassembler::Fail;
4759     case 0:
4760       if (fieldFromInstruction(Insn, 4, 1))
4761         return MCDisassembler::Fail; // UNDEFINED
4762       index = fieldFromInstruction(Insn, 5, 3);
4763       break;
4764     case 1:
4765       if (fieldFromInstruction(Insn, 5, 1))
4766         return MCDisassembler::Fail; // UNDEFINED
4767       index = fieldFromInstruction(Insn, 6, 2);
4768       if (fieldFromInstruction(Insn, 4, 1))
4769         align = 2;
4770       break;
4771     case 2:
4772       if (fieldFromInstruction(Insn, 6, 1))
4773         return MCDisassembler::Fail; // UNDEFINED
4774       index = fieldFromInstruction(Insn, 7, 1);
4775 
4776       switch (fieldFromInstruction(Insn, 4, 2)) {
4777         case 0:
4778           align = 0; break;
4779         case 3:
4780           align = 4; break;
4781         default:
4782           return MCDisassembler::Fail;
4783       }
4784       break;
4785   }
4786 
4787   if (Rm != 0xF) { // Writeback
4788     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4789     return MCDisassembler::Fail;
4790   }
4791   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4792     return MCDisassembler::Fail;
4793   Inst.addOperand(MCOperand::createImm(align));
4794   if (Rm != 0xF) {
4795     if (Rm != 0xD) {
4796       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4797     return MCDisassembler::Fail;
4798     } else
4799       Inst.addOperand(MCOperand::createReg(0));
4800   }
4801 
4802   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4803     return MCDisassembler::Fail;
4804   Inst.addOperand(MCOperand::createImm(index));
4805 
4806   return S;
4807 }
4808 
4809 static DecodeStatus DecodeVLD2LN(MCInst &Inst, unsigned Insn,
4810                          uint64_t Address, const void *Decoder) {
4811   DecodeStatus S = MCDisassembler::Success;
4812 
4813   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4814   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4815   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4816   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4817   unsigned size = fieldFromInstruction(Insn, 10, 2);
4818 
4819   unsigned align = 0;
4820   unsigned index = 0;
4821   unsigned inc = 1;
4822   switch (size) {
4823     default:
4824       return MCDisassembler::Fail;
4825     case 0:
4826       index = fieldFromInstruction(Insn, 5, 3);
4827       if (fieldFromInstruction(Insn, 4, 1))
4828         align = 2;
4829       break;
4830     case 1:
4831       index = fieldFromInstruction(Insn, 6, 2);
4832       if (fieldFromInstruction(Insn, 4, 1))
4833         align = 4;
4834       if (fieldFromInstruction(Insn, 5, 1))
4835         inc = 2;
4836       break;
4837     case 2:
4838       if (fieldFromInstruction(Insn, 5, 1))
4839         return MCDisassembler::Fail; // UNDEFINED
4840       index = fieldFromInstruction(Insn, 7, 1);
4841       if (fieldFromInstruction(Insn, 4, 1) != 0)
4842         align = 8;
4843       if (fieldFromInstruction(Insn, 6, 1))
4844         inc = 2;
4845       break;
4846   }
4847 
4848   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4849     return MCDisassembler::Fail;
4850   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4851     return MCDisassembler::Fail;
4852   if (Rm != 0xF) { // Writeback
4853     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4854       return MCDisassembler::Fail;
4855   }
4856   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4857     return MCDisassembler::Fail;
4858   Inst.addOperand(MCOperand::createImm(align));
4859   if (Rm != 0xF) {
4860     if (Rm != 0xD) {
4861       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4862         return MCDisassembler::Fail;
4863     } else
4864       Inst.addOperand(MCOperand::createReg(0));
4865   }
4866 
4867   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4868     return MCDisassembler::Fail;
4869   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4870     return MCDisassembler::Fail;
4871   Inst.addOperand(MCOperand::createImm(index));
4872 
4873   return S;
4874 }
4875 
4876 static DecodeStatus DecodeVST2LN(MCInst &Inst, unsigned Insn,
4877                          uint64_t Address, const void *Decoder) {
4878   DecodeStatus S = MCDisassembler::Success;
4879 
4880   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4881   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4882   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4883   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4884   unsigned size = fieldFromInstruction(Insn, 10, 2);
4885 
4886   unsigned align = 0;
4887   unsigned index = 0;
4888   unsigned inc = 1;
4889   switch (size) {
4890     default:
4891       return MCDisassembler::Fail;
4892     case 0:
4893       index = fieldFromInstruction(Insn, 5, 3);
4894       if (fieldFromInstruction(Insn, 4, 1))
4895         align = 2;
4896       break;
4897     case 1:
4898       index = fieldFromInstruction(Insn, 6, 2);
4899       if (fieldFromInstruction(Insn, 4, 1))
4900         align = 4;
4901       if (fieldFromInstruction(Insn, 5, 1))
4902         inc = 2;
4903       break;
4904     case 2:
4905       if (fieldFromInstruction(Insn, 5, 1))
4906         return MCDisassembler::Fail; // UNDEFINED
4907       index = fieldFromInstruction(Insn, 7, 1);
4908       if (fieldFromInstruction(Insn, 4, 1) != 0)
4909         align = 8;
4910       if (fieldFromInstruction(Insn, 6, 1))
4911         inc = 2;
4912       break;
4913   }
4914 
4915   if (Rm != 0xF) { // Writeback
4916     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4917       return MCDisassembler::Fail;
4918   }
4919   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4920     return MCDisassembler::Fail;
4921   Inst.addOperand(MCOperand::createImm(align));
4922   if (Rm != 0xF) {
4923     if (Rm != 0xD) {
4924       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4925         return MCDisassembler::Fail;
4926     } else
4927       Inst.addOperand(MCOperand::createReg(0));
4928   }
4929 
4930   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4931     return MCDisassembler::Fail;
4932   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4933     return MCDisassembler::Fail;
4934   Inst.addOperand(MCOperand::createImm(index));
4935 
4936   return S;
4937 }
4938 
4939 static DecodeStatus DecodeVLD3LN(MCInst &Inst, unsigned Insn,
4940                          uint64_t Address, const void *Decoder) {
4941   DecodeStatus S = MCDisassembler::Success;
4942 
4943   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4944   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4945   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4946   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4947   unsigned size = fieldFromInstruction(Insn, 10, 2);
4948 
4949   unsigned align = 0;
4950   unsigned index = 0;
4951   unsigned inc = 1;
4952   switch (size) {
4953     default:
4954       return MCDisassembler::Fail;
4955     case 0:
4956       if (fieldFromInstruction(Insn, 4, 1))
4957         return MCDisassembler::Fail; // UNDEFINED
4958       index = fieldFromInstruction(Insn, 5, 3);
4959       break;
4960     case 1:
4961       if (fieldFromInstruction(Insn, 4, 1))
4962         return MCDisassembler::Fail; // UNDEFINED
4963       index = fieldFromInstruction(Insn, 6, 2);
4964       if (fieldFromInstruction(Insn, 5, 1))
4965         inc = 2;
4966       break;
4967     case 2:
4968       if (fieldFromInstruction(Insn, 4, 2))
4969         return MCDisassembler::Fail; // UNDEFINED
4970       index = fieldFromInstruction(Insn, 7, 1);
4971       if (fieldFromInstruction(Insn, 6, 1))
4972         inc = 2;
4973       break;
4974   }
4975 
4976   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4977     return MCDisassembler::Fail;
4978   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4979     return MCDisassembler::Fail;
4980   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4981     return MCDisassembler::Fail;
4982 
4983   if (Rm != 0xF) { // Writeback
4984     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4985     return MCDisassembler::Fail;
4986   }
4987   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4988     return MCDisassembler::Fail;
4989   Inst.addOperand(MCOperand::createImm(align));
4990   if (Rm != 0xF) {
4991     if (Rm != 0xD) {
4992       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4993     return MCDisassembler::Fail;
4994     } else
4995       Inst.addOperand(MCOperand::createReg(0));
4996   }
4997 
4998   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4999     return MCDisassembler::Fail;
5000   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
5001     return MCDisassembler::Fail;
5002   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
5003     return MCDisassembler::Fail;
5004   Inst.addOperand(MCOperand::createImm(index));
5005 
5006   return S;
5007 }
5008 
5009 static DecodeStatus DecodeVST3LN(MCInst &Inst, unsigned Insn,
5010                          uint64_t Address, const void *Decoder) {
5011   DecodeStatus S = MCDisassembler::Success;
5012 
5013   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5014   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
5015   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
5016   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
5017   unsigned size = fieldFromInstruction(Insn, 10, 2);
5018 
5019   unsigned align = 0;
5020   unsigned index = 0;
5021   unsigned inc = 1;
5022   switch (size) {
5023     default:
5024       return MCDisassembler::Fail;
5025     case 0:
5026       if (fieldFromInstruction(Insn, 4, 1))
5027         return MCDisassembler::Fail; // UNDEFINED
5028       index = fieldFromInstruction(Insn, 5, 3);
5029       break;
5030     case 1:
5031       if (fieldFromInstruction(Insn, 4, 1))
5032         return MCDisassembler::Fail; // UNDEFINED
5033       index = fieldFromInstruction(Insn, 6, 2);
5034       if (fieldFromInstruction(Insn, 5, 1))
5035         inc = 2;
5036       break;
5037     case 2:
5038       if (fieldFromInstruction(Insn, 4, 2))
5039         return MCDisassembler::Fail; // UNDEFINED
5040       index = fieldFromInstruction(Insn, 7, 1);
5041       if (fieldFromInstruction(Insn, 6, 1))
5042         inc = 2;
5043       break;
5044   }
5045 
5046   if (Rm != 0xF) { // Writeback
5047     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5048     return MCDisassembler::Fail;
5049   }
5050   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5051     return MCDisassembler::Fail;
5052   Inst.addOperand(MCOperand::createImm(align));
5053   if (Rm != 0xF) {
5054     if (Rm != 0xD) {
5055       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
5056     return MCDisassembler::Fail;
5057     } else
5058       Inst.addOperand(MCOperand::createReg(0));
5059   }
5060 
5061   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
5062     return MCDisassembler::Fail;
5063   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
5064     return MCDisassembler::Fail;
5065   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
5066     return MCDisassembler::Fail;
5067   Inst.addOperand(MCOperand::createImm(index));
5068 
5069   return S;
5070 }
5071 
5072 static DecodeStatus DecodeVLD4LN(MCInst &Inst, unsigned Insn,
5073                          uint64_t Address, const void *Decoder) {
5074   DecodeStatus S = MCDisassembler::Success;
5075 
5076   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5077   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
5078   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
5079   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
5080   unsigned size = fieldFromInstruction(Insn, 10, 2);
5081 
5082   unsigned align = 0;
5083   unsigned index = 0;
5084   unsigned inc = 1;
5085   switch (size) {
5086     default:
5087       return MCDisassembler::Fail;
5088     case 0:
5089       if (fieldFromInstruction(Insn, 4, 1))
5090         align = 4;
5091       index = fieldFromInstruction(Insn, 5, 3);
5092       break;
5093     case 1:
5094       if (fieldFromInstruction(Insn, 4, 1))
5095         align = 8;
5096       index = fieldFromInstruction(Insn, 6, 2);
5097       if (fieldFromInstruction(Insn, 5, 1))
5098         inc = 2;
5099       break;
5100     case 2:
5101       switch (fieldFromInstruction(Insn, 4, 2)) {
5102         case 0:
5103           align = 0; break;
5104         case 3:
5105           return MCDisassembler::Fail;
5106         default:
5107           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
5108       }
5109 
5110       index = fieldFromInstruction(Insn, 7, 1);
5111       if (fieldFromInstruction(Insn, 6, 1))
5112         inc = 2;
5113       break;
5114   }
5115 
5116   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
5117     return MCDisassembler::Fail;
5118   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
5119     return MCDisassembler::Fail;
5120   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
5121     return MCDisassembler::Fail;
5122   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
5123     return MCDisassembler::Fail;
5124 
5125   if (Rm != 0xF) { // Writeback
5126     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5127       return MCDisassembler::Fail;
5128   }
5129   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5130     return MCDisassembler::Fail;
5131   Inst.addOperand(MCOperand::createImm(align));
5132   if (Rm != 0xF) {
5133     if (Rm != 0xD) {
5134       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
5135         return MCDisassembler::Fail;
5136     } else
5137       Inst.addOperand(MCOperand::createReg(0));
5138   }
5139 
5140   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
5141     return MCDisassembler::Fail;
5142   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
5143     return MCDisassembler::Fail;
5144   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
5145     return MCDisassembler::Fail;
5146   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
5147     return MCDisassembler::Fail;
5148   Inst.addOperand(MCOperand::createImm(index));
5149 
5150   return S;
5151 }
5152 
5153 static DecodeStatus DecodeVST4LN(MCInst &Inst, unsigned Insn,
5154                          uint64_t Address, const void *Decoder) {
5155   DecodeStatus S = MCDisassembler::Success;
5156 
5157   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5158   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
5159   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
5160   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
5161   unsigned size = fieldFromInstruction(Insn, 10, 2);
5162 
5163   unsigned align = 0;
5164   unsigned index = 0;
5165   unsigned inc = 1;
5166   switch (size) {
5167     default:
5168       return MCDisassembler::Fail;
5169     case 0:
5170       if (fieldFromInstruction(Insn, 4, 1))
5171         align = 4;
5172       index = fieldFromInstruction(Insn, 5, 3);
5173       break;
5174     case 1:
5175       if (fieldFromInstruction(Insn, 4, 1))
5176         align = 8;
5177       index = fieldFromInstruction(Insn, 6, 2);
5178       if (fieldFromInstruction(Insn, 5, 1))
5179         inc = 2;
5180       break;
5181     case 2:
5182       switch (fieldFromInstruction(Insn, 4, 2)) {
5183         case 0:
5184           align = 0; break;
5185         case 3:
5186           return MCDisassembler::Fail;
5187         default:
5188           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
5189       }
5190 
5191       index = fieldFromInstruction(Insn, 7, 1);
5192       if (fieldFromInstruction(Insn, 6, 1))
5193         inc = 2;
5194       break;
5195   }
5196 
5197   if (Rm != 0xF) { // Writeback
5198     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5199     return MCDisassembler::Fail;
5200   }
5201   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
5202     return MCDisassembler::Fail;
5203   Inst.addOperand(MCOperand::createImm(align));
5204   if (Rm != 0xF) {
5205     if (Rm != 0xD) {
5206       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
5207     return MCDisassembler::Fail;
5208     } else
5209       Inst.addOperand(MCOperand::createReg(0));
5210   }
5211 
5212   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
5213     return MCDisassembler::Fail;
5214   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
5215     return MCDisassembler::Fail;
5216   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
5217     return MCDisassembler::Fail;
5218   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
5219     return MCDisassembler::Fail;
5220   Inst.addOperand(MCOperand::createImm(index));
5221 
5222   return S;
5223 }
5224 
5225 static DecodeStatus DecodeVMOVSRR(MCInst &Inst, unsigned Insn,
5226                                   uint64_t Address, const void *Decoder) {
5227   DecodeStatus S = MCDisassembler::Success;
5228   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
5229   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
5230   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
5231   unsigned pred = fieldFromInstruction(Insn, 28, 4);
5232   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
5233 
5234   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
5235     S = MCDisassembler::SoftFail;
5236 
5237   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
5238     return MCDisassembler::Fail;
5239   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
5240     return MCDisassembler::Fail;
5241   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
5242     return MCDisassembler::Fail;
5243   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
5244     return MCDisassembler::Fail;
5245   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5246     return MCDisassembler::Fail;
5247 
5248   return S;
5249 }
5250 
5251 static DecodeStatus DecodeVMOVRRS(MCInst &Inst, unsigned Insn,
5252                                   uint64_t Address, const void *Decoder) {
5253   DecodeStatus S = MCDisassembler::Success;
5254   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
5255   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
5256   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
5257   unsigned pred = fieldFromInstruction(Insn, 28, 4);
5258   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
5259 
5260   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
5261     S = MCDisassembler::SoftFail;
5262 
5263   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
5264     return MCDisassembler::Fail;
5265   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
5266     return MCDisassembler::Fail;
5267   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
5268     return MCDisassembler::Fail;
5269   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
5270     return MCDisassembler::Fail;
5271   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5272     return MCDisassembler::Fail;
5273 
5274   return S;
5275 }
5276 
5277 static DecodeStatus DecodeIT(MCInst &Inst, unsigned Insn,
5278                              uint64_t Address, const void *Decoder) {
5279   DecodeStatus S = MCDisassembler::Success;
5280   unsigned pred = fieldFromInstruction(Insn, 4, 4);
5281   unsigned mask = fieldFromInstruction(Insn, 0, 4);
5282 
5283   if (pred == 0xF) {
5284     pred = 0xE;
5285     S = MCDisassembler::SoftFail;
5286   }
5287 
5288   if (mask == 0x0)
5289     return MCDisassembler::Fail;
5290 
5291   // IT masks are encoded as a sequence of replacement low-order bits
5292   // for the condition code. So if the low bit of the starting
5293   // condition code is 1, then we have to flip all the bits above the
5294   // terminating bit (which is the lowest 1 bit).
5295   if (pred & 1) {
5296     unsigned LowBit = mask & -mask;
5297     unsigned BitsAboveLowBit = 0xF & (-LowBit << 1);
5298     mask ^= BitsAboveLowBit;
5299   }
5300 
5301   Inst.addOperand(MCOperand::createImm(pred));
5302   Inst.addOperand(MCOperand::createImm(mask));
5303   return S;
5304 }
5305 
5306 static DecodeStatus
5307 DecodeT2LDRDPreInstruction(MCInst &Inst, unsigned Insn,
5308                            uint64_t Address, const void *Decoder) {
5309   DecodeStatus S = MCDisassembler::Success;
5310 
5311   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
5312   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
5313   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5314   unsigned addr = fieldFromInstruction(Insn, 0, 8);
5315   unsigned W = fieldFromInstruction(Insn, 21, 1);
5316   unsigned U = fieldFromInstruction(Insn, 23, 1);
5317   unsigned P = fieldFromInstruction(Insn, 24, 1);
5318   bool writeback = (W == 1) | (P == 0);
5319 
5320   addr |= (U << 8) | (Rn << 9);
5321 
5322   if (writeback && (Rn == Rt || Rn == Rt2))
5323     Check(S, MCDisassembler::SoftFail);
5324   if (Rt == Rt2)
5325     Check(S, MCDisassembler::SoftFail);
5326 
5327   // Rt
5328   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
5329     return MCDisassembler::Fail;
5330   // Rt2
5331   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
5332     return MCDisassembler::Fail;
5333   // Writeback operand
5334   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
5335     return MCDisassembler::Fail;
5336   // addr
5337   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
5338     return MCDisassembler::Fail;
5339 
5340   return S;
5341 }
5342 
5343 static DecodeStatus
5344 DecodeT2STRDPreInstruction(MCInst &Inst, unsigned Insn,
5345                            uint64_t Address, const void *Decoder) {
5346   DecodeStatus S = MCDisassembler::Success;
5347 
5348   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
5349   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
5350   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5351   unsigned addr = fieldFromInstruction(Insn, 0, 8);
5352   unsigned W = fieldFromInstruction(Insn, 21, 1);
5353   unsigned U = fieldFromInstruction(Insn, 23, 1);
5354   unsigned P = fieldFromInstruction(Insn, 24, 1);
5355   bool writeback = (W == 1) | (P == 0);
5356 
5357   addr |= (U << 8) | (Rn << 9);
5358 
5359   if (writeback && (Rn == Rt || Rn == Rt2))
5360     Check(S, MCDisassembler::SoftFail);
5361 
5362   // Writeback operand
5363   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
5364     return MCDisassembler::Fail;
5365   // Rt
5366   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
5367     return MCDisassembler::Fail;
5368   // Rt2
5369   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
5370     return MCDisassembler::Fail;
5371   // addr
5372   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
5373     return MCDisassembler::Fail;
5374 
5375   return S;
5376 }
5377 
5378 static DecodeStatus DecodeT2Adr(MCInst &Inst, uint32_t Insn,
5379                                 uint64_t Address, const void *Decoder) {
5380   unsigned sign1 = fieldFromInstruction(Insn, 21, 1);
5381   unsigned sign2 = fieldFromInstruction(Insn, 23, 1);
5382   if (sign1 != sign2) return MCDisassembler::Fail;
5383 
5384   unsigned Val = fieldFromInstruction(Insn, 0, 8);
5385   Val |= fieldFromInstruction(Insn, 12, 3) << 8;
5386   Val |= fieldFromInstruction(Insn, 26, 1) << 11;
5387   Val |= sign1 << 12;
5388   Inst.addOperand(MCOperand::createImm(SignExtend32<13>(Val)));
5389 
5390   return MCDisassembler::Success;
5391 }
5392 
5393 static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, uint32_t Val,
5394                                               uint64_t Address,
5395                                               const void *Decoder) {
5396   DecodeStatus S = MCDisassembler::Success;
5397 
5398   // Shift of "asr #32" is not allowed in Thumb2 mode.
5399   if (Val == 0x20) S = MCDisassembler::Fail;
5400   Inst.addOperand(MCOperand::createImm(Val));
5401   return S;
5402 }
5403 
5404 static DecodeStatus DecodeSwap(MCInst &Inst, unsigned Insn,
5405                                uint64_t Address, const void *Decoder) {
5406   unsigned Rt   = fieldFromInstruction(Insn, 12, 4);
5407   unsigned Rt2  = fieldFromInstruction(Insn, 0,  4);
5408   unsigned Rn   = fieldFromInstruction(Insn, 16, 4);
5409   unsigned pred = fieldFromInstruction(Insn, 28, 4);
5410 
5411   if (pred == 0xF)
5412     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
5413 
5414   DecodeStatus S = MCDisassembler::Success;
5415 
5416   if (Rt == Rn || Rn == Rt2)
5417     S = MCDisassembler::SoftFail;
5418 
5419   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5420     return MCDisassembler::Fail;
5421   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5422     return MCDisassembler::Fail;
5423   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
5424     return MCDisassembler::Fail;
5425   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5426     return MCDisassembler::Fail;
5427 
5428   return S;
5429 }
5430 
5431 static DecodeStatus DecodeVCVTD(MCInst &Inst, unsigned Insn,
5432                                 uint64_t Address, const void *Decoder) {
5433   const FeatureBitset &featureBits =
5434       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5435   bool hasFullFP16 = featureBits[ARM::FeatureFullFP16];
5436 
5437   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5438   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5439   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5440   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5441   unsigned imm = fieldFromInstruction(Insn, 16, 6);
5442   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
5443   unsigned op = fieldFromInstruction(Insn, 5, 1);
5444 
5445   DecodeStatus S = MCDisassembler::Success;
5446 
5447   // If the top 3 bits of imm are clear, this is a VMOV (immediate)
5448   if (!(imm & 0x38)) {
5449     if (cmode == 0xF) {
5450       if (op == 1) return MCDisassembler::Fail;
5451       Inst.setOpcode(ARM::VMOVv2f32);
5452     }
5453     if (hasFullFP16) {
5454       if (cmode == 0xE) {
5455         if (op == 1) {
5456           Inst.setOpcode(ARM::VMOVv1i64);
5457         } else {
5458           Inst.setOpcode(ARM::VMOVv8i8);
5459         }
5460       }
5461       if (cmode == 0xD) {
5462         if (op == 1) {
5463           Inst.setOpcode(ARM::VMVNv2i32);
5464         } else {
5465           Inst.setOpcode(ARM::VMOVv2i32);
5466         }
5467       }
5468       if (cmode == 0xC) {
5469         if (op == 1) {
5470           Inst.setOpcode(ARM::VMVNv2i32);
5471         } else {
5472           Inst.setOpcode(ARM::VMOVv2i32);
5473         }
5474       }
5475     }
5476     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
5477   }
5478 
5479   if (!(imm & 0x20)) return MCDisassembler::Fail;
5480 
5481   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
5482     return MCDisassembler::Fail;
5483   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
5484     return MCDisassembler::Fail;
5485   Inst.addOperand(MCOperand::createImm(64 - imm));
5486 
5487   return S;
5488 }
5489 
5490 static DecodeStatus DecodeVCVTQ(MCInst &Inst, unsigned Insn,
5491                                 uint64_t Address, const void *Decoder) {
5492   const FeatureBitset &featureBits =
5493       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5494   bool hasFullFP16 = featureBits[ARM::FeatureFullFP16];
5495 
5496   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5497   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5498   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5499   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5500   unsigned imm = fieldFromInstruction(Insn, 16, 6);
5501   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
5502   unsigned op = fieldFromInstruction(Insn, 5, 1);
5503 
5504   DecodeStatus S = MCDisassembler::Success;
5505 
5506   // If the top 3 bits of imm are clear, this is a VMOV (immediate)
5507   if (!(imm & 0x38)) {
5508     if (cmode == 0xF) {
5509       if (op == 1) return MCDisassembler::Fail;
5510       Inst.setOpcode(ARM::VMOVv4f32);
5511     }
5512     if (hasFullFP16) {
5513       if (cmode == 0xE) {
5514         if (op == 1) {
5515           Inst.setOpcode(ARM::VMOVv2i64);
5516         } else {
5517           Inst.setOpcode(ARM::VMOVv16i8);
5518         }
5519       }
5520       if (cmode == 0xD) {
5521         if (op == 1) {
5522           Inst.setOpcode(ARM::VMVNv4i32);
5523         } else {
5524           Inst.setOpcode(ARM::VMOVv4i32);
5525         }
5526       }
5527       if (cmode == 0xC) {
5528         if (op == 1) {
5529           Inst.setOpcode(ARM::VMVNv4i32);
5530         } else {
5531           Inst.setOpcode(ARM::VMOVv4i32);
5532         }
5533       }
5534     }
5535     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
5536   }
5537 
5538   if (!(imm & 0x20)) return MCDisassembler::Fail;
5539 
5540   if (!Check(S, DecodeQPRRegisterClass(Inst, Vd, Address, Decoder)))
5541     return MCDisassembler::Fail;
5542   if (!Check(S, DecodeQPRRegisterClass(Inst, Vm, Address, Decoder)))
5543     return MCDisassembler::Fail;
5544   Inst.addOperand(MCOperand::createImm(64 - imm));
5545 
5546   return S;
5547 }
5548 
5549 static DecodeStatus DecodeNEONComplexLane64Instruction(MCInst &Inst,
5550                                                        unsigned Insn,
5551                                                        uint64_t Address,
5552                                                        const void *Decoder) {
5553   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5554   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5555   unsigned Vn = (fieldFromInstruction(Insn, 16, 4) << 0);
5556   Vn |= (fieldFromInstruction(Insn, 7, 1) << 4);
5557   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5558   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5559   unsigned q = (fieldFromInstruction(Insn, 6, 1) << 0);
5560   unsigned rotate = (fieldFromInstruction(Insn, 20, 2) << 0);
5561 
5562   DecodeStatus S = MCDisassembler::Success;
5563 
5564   auto DestRegDecoder = q ? DecodeQPRRegisterClass : DecodeDPRRegisterClass;
5565 
5566   if (!Check(S, DestRegDecoder(Inst, Vd, Address, Decoder)))
5567     return MCDisassembler::Fail;
5568   if (!Check(S, DestRegDecoder(Inst, Vd, Address, Decoder)))
5569     return MCDisassembler::Fail;
5570   if (!Check(S, DestRegDecoder(Inst, Vn, Address, Decoder)))
5571     return MCDisassembler::Fail;
5572   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
5573     return MCDisassembler::Fail;
5574   // The lane index does not have any bits in the encoding, because it can only
5575   // be 0.
5576   Inst.addOperand(MCOperand::createImm(0));
5577   Inst.addOperand(MCOperand::createImm(rotate));
5578 
5579   return S;
5580 }
5581 
5582 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
5583                                 uint64_t Address, const void *Decoder) {
5584   DecodeStatus S = MCDisassembler::Success;
5585 
5586   unsigned Rn = fieldFromInstruction(Val, 16, 4);
5587   unsigned Rt = fieldFromInstruction(Val, 12, 4);
5588   unsigned Rm = fieldFromInstruction(Val, 0, 4);
5589   Rm |= (fieldFromInstruction(Val, 23, 1) << 4);
5590   unsigned Cond = fieldFromInstruction(Val, 28, 4);
5591 
5592   if (fieldFromInstruction(Val, 8, 4) != 0 || Rn == Rt)
5593     S = MCDisassembler::SoftFail;
5594 
5595   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5596     return MCDisassembler::Fail;
5597   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
5598     return MCDisassembler::Fail;
5599   if (!Check(S, DecodeAddrMode7Operand(Inst, Rn, Address, Decoder)))
5600     return MCDisassembler::Fail;
5601   if (!Check(S, DecodePostIdxReg(Inst, Rm, Address, Decoder)))
5602     return MCDisassembler::Fail;
5603   if (!Check(S, DecodePredicateOperand(Inst, Cond, Address, Decoder)))
5604     return MCDisassembler::Fail;
5605 
5606   return S;
5607 }
5608 
5609 static DecodeStatus DecoderForMRRC2AndMCRR2(MCInst &Inst, unsigned Val,
5610                                             uint64_t Address, const void *Decoder) {
5611   DecodeStatus S = MCDisassembler::Success;
5612 
5613   unsigned CRm = fieldFromInstruction(Val, 0, 4);
5614   unsigned opc1 = fieldFromInstruction(Val, 4, 4);
5615   unsigned cop = fieldFromInstruction(Val, 8, 4);
5616   unsigned Rt = fieldFromInstruction(Val, 12, 4);
5617   unsigned Rt2 = fieldFromInstruction(Val, 16, 4);
5618 
5619   if ((cop & ~0x1) == 0xa)
5620     return MCDisassembler::Fail;
5621 
5622   if (Rt == Rt2)
5623     S = MCDisassembler::SoftFail;
5624 
5625   // We have to check if the instruction is MRRC2
5626   // or MCRR2 when constructing the operands for
5627   // Inst. Reason is because MRRC2 stores to two
5628   // registers so it's tablegen desc has has two
5629   // outputs whereas MCRR doesn't store to any
5630   // registers so all of it's operands are listed
5631   // as inputs, therefore the operand order for
5632   // MRRC2 needs to be [Rt, Rt2, cop, opc1, CRm]
5633   // and MCRR2 operand order is [cop, opc1, Rt, Rt2, CRm]
5634 
5635   if (Inst.getOpcode() == ARM::MRRC2) {
5636     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5637       return MCDisassembler::Fail;
5638     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5639       return MCDisassembler::Fail;
5640   }
5641   Inst.addOperand(MCOperand::createImm(cop));
5642   Inst.addOperand(MCOperand::createImm(opc1));
5643   if (Inst.getOpcode() == ARM::MCRR2) {
5644     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5645       return MCDisassembler::Fail;
5646     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5647       return MCDisassembler::Fail;
5648   }
5649   Inst.addOperand(MCOperand::createImm(CRm));
5650 
5651   return S;
5652 }
5653 
5654 static DecodeStatus DecodeForVMRSandVMSR(MCInst &Inst, unsigned Val,
5655                                          uint64_t Address,
5656                                          const void *Decoder) {
5657   const FeatureBitset &featureBits =
5658       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5659   DecodeStatus S = MCDisassembler::Success;
5660 
5661   // Add explicit operand for the destination sysreg, for cases where
5662   // we have to model it for code generation purposes.
5663   switch (Inst.getOpcode()) {
5664   case ARM::VMSR_FPSCR_NZCVQC:
5665     Inst.addOperand(MCOperand::createReg(ARM::FPSCR_NZCV));
5666     break;
5667   case ARM::VMSR_P0:
5668     Inst.addOperand(MCOperand::createReg(ARM::VPR));
5669     break;
5670   }
5671 
5672   if (Inst.getOpcode() != ARM::FMSTAT) {
5673     unsigned Rt = fieldFromInstruction(Val, 12, 4);
5674 
5675     if (featureBits[ARM::ModeThumb] && !featureBits[ARM::HasV8Ops]) {
5676       if (Rt == 13 || Rt == 15)
5677         S = MCDisassembler::SoftFail;
5678       Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
5679     } else
5680       Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder));
5681   }
5682 
5683   // Add explicit operand for the source sysreg, similarly to above.
5684   switch (Inst.getOpcode()) {
5685   case ARM::VMRS_FPSCR_NZCVQC:
5686     Inst.addOperand(MCOperand::createReg(ARM::FPSCR_NZCV));
5687     break;
5688   case ARM::VMRS_P0:
5689     Inst.addOperand(MCOperand::createReg(ARM::VPR));
5690     break;
5691   }
5692 
5693   if (featureBits[ARM::ModeThumb]) {
5694     Inst.addOperand(MCOperand::createImm(ARMCC::AL));
5695     Inst.addOperand(MCOperand::createReg(0));
5696   } else {
5697     unsigned pred = fieldFromInstruction(Val, 28, 4);
5698     if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5699       return MCDisassembler::Fail;
5700   }
5701 
5702   return S;
5703 }
5704 
5705 template <bool isSigned, bool isNeg, int size>
5706 static DecodeStatus DecodeBFLabelOperand(MCInst &Inst, unsigned Val,
5707                                          uint64_t Address,
5708                                          const void *Decoder) {
5709   DecodeStatus S = MCDisassembler::Success;
5710   if (Val == 0)
5711     S = MCDisassembler::SoftFail;
5712 
5713   uint64_t DecVal;
5714   if (isSigned)
5715     DecVal = SignExtend32<size + 1>(Val << 1);
5716   else
5717     DecVal = (Val << 1);
5718 
5719   if (!tryAddingSymbolicOperand(Address, Address + DecVal + 4, true, 4, Inst,
5720                                 Decoder))
5721     Inst.addOperand(MCOperand::createImm(isNeg ? -DecVal : DecVal));
5722   return S;
5723 }
5724 
5725 static DecodeStatus DecodeBFAfterTargetOperand(MCInst &Inst, unsigned Val,
5726                                                uint64_t Address,
5727                                                const void *Decoder) {
5728 
5729   uint64_t LocImm = Inst.getOperand(0).getImm();
5730   Val = LocImm + (2 << Val);
5731   if (!tryAddingSymbolicOperand(Address, Address + Val + 4, true, 4, Inst,
5732                                 Decoder))
5733     Inst.addOperand(MCOperand::createImm(Val));
5734   return MCDisassembler::Success;
5735 }
5736 
5737 static DecodeStatus DecodePredNoALOperand(MCInst &Inst, unsigned Val,
5738                                           uint64_t Address,
5739                                           const void *Decoder) {
5740   if (Val >= ARMCC::AL)  // also exclude the non-condition NV
5741     return MCDisassembler::Fail;
5742   Inst.addOperand(MCOperand::createImm(Val));
5743   return MCDisassembler::Success;
5744 }
5745 
5746 static DecodeStatus DecodeLOLoop(MCInst &Inst, unsigned Insn, uint64_t Address,
5747                                  const void *Decoder) {
5748   DecodeStatus S = MCDisassembler::Success;
5749 
5750   unsigned Imm = fieldFromInstruction(Insn, 11, 1) |
5751                  fieldFromInstruction(Insn, 1, 10) << 1;
5752   switch (Inst.getOpcode()) {
5753   case ARM::t2LEUpdate:
5754     Inst.addOperand(MCOperand::createReg(ARM::LR));
5755     Inst.addOperand(MCOperand::createReg(ARM::LR));
5756     LLVM_FALLTHROUGH;
5757   case ARM::t2LE:
5758     if (!Check(S, DecodeBFLabelOperand<false, true, 11>(Inst, Imm, Address,
5759                                                         Decoder)))
5760       return MCDisassembler::Fail;
5761     break;
5762   case ARM::t2WLS:
5763     Inst.addOperand(MCOperand::createReg(ARM::LR));
5764     if (!Check(S,
5765                DecoderGPRRegisterClass(Inst, fieldFromInstruction(Insn, 16, 4),
5766                                        Address, Decoder)) ||
5767         !Check(S, DecodeBFLabelOperand<false, false, 11>(Inst, Imm, Address,
5768                                                          Decoder)))
5769       return MCDisassembler::Fail;
5770     break;
5771   case ARM::t2DLS:
5772     unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5773     if (Rn == 0xF) {
5774       return MCDisassembler::Fail;
5775     } else {
5776       Inst.addOperand(MCOperand::createReg(ARM::LR));
5777       if (!Check(S, DecoderGPRRegisterClass(Inst,
5778                                             fieldFromInstruction(Insn, 16, 4),
5779                                             Address, Decoder)))
5780         return MCDisassembler::Fail;
5781     }
5782     break;
5783   }
5784   return S;
5785 }
5786 
5787 static DecodeStatus DecodeLongShiftOperand(MCInst &Inst, unsigned Val,
5788                                            uint64_t Address,
5789                                            const void *Decoder) {
5790   DecodeStatus S = MCDisassembler::Success;
5791 
5792   if (Val == 0)
5793     Val = 32;
5794 
5795   Inst.addOperand(MCOperand::createImm(Val));
5796 
5797   return S;
5798 }
5799 
5800 static DecodeStatus DecodetGPROddRegisterClass(MCInst &Inst, unsigned RegNo,
5801                                    uint64_t Address, const void *Decoder) {
5802   if ((RegNo) + 1 > 11)
5803     return MCDisassembler::Fail;
5804 
5805   unsigned Register = GPRDecoderTable[(RegNo) + 1];
5806   Inst.addOperand(MCOperand::createReg(Register));
5807   return MCDisassembler::Success;
5808 }
5809 
5810 static DecodeStatus DecodetGPREvenRegisterClass(MCInst &Inst, unsigned RegNo,
5811                                    uint64_t Address, const void *Decoder) {
5812   if ((RegNo) > 14)
5813     return MCDisassembler::Fail;
5814 
5815   unsigned Register = GPRDecoderTable[(RegNo)];
5816   Inst.addOperand(MCOperand::createReg(Register));
5817   return MCDisassembler::Success;
5818 }
5819 
5820 static DecodeStatus DecodeVSCCLRM(MCInst &Inst, unsigned Insn, uint64_t Address,
5821                                   const void *Decoder) {
5822   DecodeStatus S = MCDisassembler::Success;
5823 
5824   Inst.addOperand(MCOperand::createImm(ARMCC::AL));
5825   Inst.addOperand(MCOperand::createReg(0));
5826   if (Inst.getOpcode() == ARM::VSCCLRMD) {
5827     unsigned reglist = (fieldFromInstruction(Insn, 1, 7) << 1) |
5828                        (fieldFromInstruction(Insn, 12, 4) << 8) |
5829                        (fieldFromInstruction(Insn, 22, 1) << 12);
5830     if (!Check(S, DecodeDPRRegListOperand(Inst, reglist, Address, Decoder))) {
5831       return MCDisassembler::Fail;
5832     }
5833   } else {
5834     unsigned reglist = fieldFromInstruction(Insn, 0, 8) |
5835                        (fieldFromInstruction(Insn, 22, 1) << 8) |
5836                        (fieldFromInstruction(Insn, 12, 4) << 9);
5837     if (!Check(S, DecodeSPRRegListOperand(Inst, reglist, Address, Decoder))) {
5838       return MCDisassembler::Fail;
5839     }
5840   }
5841   Inst.addOperand(MCOperand::createReg(ARM::VPR));
5842 
5843   return S;
5844 }
5845 
5846 static DecodeStatus DecodeMQPRRegisterClass(MCInst &Inst, unsigned RegNo,
5847                               uint64_t Address,
5848                               const void *Decoder) {
5849   if (RegNo > 7)
5850     return MCDisassembler::Fail;
5851 
5852   unsigned Register = QPRDecoderTable[RegNo];
5853   Inst.addOperand(MCOperand::createReg(Register));
5854   return MCDisassembler::Success;
5855 }
5856 
5857 static DecodeStatus DecodeVPTMaskOperand(MCInst &Inst, unsigned Val,
5858                                          uint64_t Address,
5859                                          const void *Decoder) {
5860   DecodeStatus S = MCDisassembler::Success;
5861 
5862   // Parse VPT mask and encode it in the MCInst as an immediate with the same
5863   // format as the it_mask.  That is, from the second 'e|t' encode 'e' as 1 and
5864   // 't' as 0 and finish with a 1.
5865   unsigned Imm = 0;
5866   // We always start with a 't'.
5867   unsigned CurBit = 0;
5868   for (int i = 3; i >= 0; --i) {
5869     // If the bit we are looking at is not the same as last one, invert the
5870     // CurBit, if it is the same leave it as is.
5871     CurBit ^= (Val >> i) & 1U;
5872 
5873     // Encode the CurBit at the right place in the immediate.
5874     Imm |= (CurBit << i);
5875 
5876     // If we are done, finish the encoding with a 1.
5877     if ((Val & ~(~0U << i)) == 0) {
5878       Imm |= 1U << i;
5879       break;
5880     }
5881   }
5882 
5883   Inst.addOperand(MCOperand::createImm(Imm));
5884 
5885   return S;
5886 }
5887 
5888 static DecodeStatus DecodeVpredROperand(MCInst &Inst, unsigned RegNo,
5889                                         uint64_t Address, const void *Decoder) {
5890   // The vpred_r operand type includes an MQPR register field derived
5891   // from the encoding. But we don't actually want to add an operand
5892   // to the MCInst at this stage, because AddThumbPredicate will do it
5893   // later, and will infer the register number from the TIED_TO
5894   // constraint. So this is a deliberately empty decoder method that
5895   // will inhibit the auto-generated disassembly code from adding an
5896   // operand at all.
5897   return MCDisassembler::Success;
5898 }
5899 
5900 static DecodeStatus DecodeRestrictedIPredicateOperand(MCInst &Inst,
5901                                                       unsigned Val,
5902                                                       uint64_t Address,
5903                                                       const void *Decoder) {
5904   Inst.addOperand(MCOperand::createImm((Val & 0x1) == 0 ? ARMCC::EQ : ARMCC::NE));
5905   return MCDisassembler::Success;
5906 }
5907 
5908 static DecodeStatus DecodeRestrictedSPredicateOperand(MCInst &Inst,
5909                                                       unsigned Val,
5910                                                       uint64_t Address,
5911                                                       const void *Decoder) {
5912   unsigned Code;
5913   switch (Val & 0x3) {
5914   case 0:
5915     Code = ARMCC::GE;
5916     break;
5917   case 1:
5918     Code = ARMCC::LT;
5919     break;
5920   case 2:
5921     Code = ARMCC::GT;
5922     break;
5923   case 3:
5924     Code = ARMCC::LE;
5925     break;
5926   }
5927   Inst.addOperand(MCOperand::createImm(Code));
5928   return MCDisassembler::Success;
5929 }
5930 
5931 static DecodeStatus DecodeRestrictedUPredicateOperand(MCInst &Inst,
5932                                                       unsigned Val,
5933                                                       uint64_t Address,
5934                                                       const void *Decoder) {
5935   Inst.addOperand(MCOperand::createImm((Val & 0x1) == 0 ? ARMCC::HS : ARMCC::HI));
5936   return MCDisassembler::Success;
5937 }
5938 
5939 static DecodeStatus DecodeRestrictedFPPredicateOperand(MCInst &Inst, unsigned Val,
5940                                                      uint64_t Address,
5941                                                      const void *Decoder) {
5942   unsigned Code;
5943   switch (Val) {
5944   default:
5945     return MCDisassembler::Fail;
5946   case 0:
5947     Code = ARMCC::EQ;
5948     break;
5949   case 1:
5950     Code = ARMCC::NE;
5951     break;
5952   case 4:
5953     Code = ARMCC::GE;
5954     break;
5955   case 5:
5956     Code = ARMCC::LT;
5957     break;
5958   case 6:
5959     Code = ARMCC::GT;
5960     break;
5961   case 7:
5962     Code = ARMCC::LE;
5963     break;
5964   }
5965 
5966   Inst.addOperand(MCOperand::createImm(Code));
5967   return MCDisassembler::Success;
5968 }
5969 
5970 static unsigned FixedRegForVSTRVLDR_SYSREG(unsigned Opcode) {
5971   switch (Opcode) {
5972   case ARM::VSTR_P0_off:
5973   case ARM::VSTR_P0_pre:
5974   case ARM::VSTR_P0_post:
5975   case ARM::VLDR_P0_off:
5976   case ARM::VLDR_P0_pre:
5977   case ARM::VLDR_P0_post:
5978     return ARM::P0;
5979   default:
5980     return 0;
5981   }
5982 }
5983 
5984 template<bool Writeback>
5985 static DecodeStatus DecodeVSTRVLDR_SYSREG(MCInst &Inst, unsigned Val,
5986                                           uint64_t Address,
5987                                           const void *Decoder) {
5988   switch (Inst.getOpcode()) {
5989   case ARM::VSTR_FPSCR_pre:
5990   case ARM::VSTR_FPSCR_NZCVQC_pre:
5991   case ARM::VLDR_FPSCR_pre:
5992   case ARM::VLDR_FPSCR_NZCVQC_pre:
5993   case ARM::VSTR_FPSCR_off:
5994   case ARM::VSTR_FPSCR_NZCVQC_off:
5995   case ARM::VLDR_FPSCR_off:
5996   case ARM::VLDR_FPSCR_NZCVQC_off:
5997   case ARM::VSTR_FPSCR_post:
5998   case ARM::VSTR_FPSCR_NZCVQC_post:
5999   case ARM::VLDR_FPSCR_post:
6000   case ARM::VLDR_FPSCR_NZCVQC_post:
6001     const FeatureBitset &featureBits =
6002         ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
6003 
6004     if (!featureBits[ARM::HasMVEIntegerOps] && !featureBits[ARM::FeatureVFP2])
6005       return MCDisassembler::Fail;
6006   }
6007 
6008   DecodeStatus S = MCDisassembler::Success;
6009   if (unsigned Sysreg = FixedRegForVSTRVLDR_SYSREG(Inst.getOpcode()))
6010     Inst.addOperand(MCOperand::createReg(Sysreg));
6011   unsigned Rn = fieldFromInstruction(Val, 16, 4);
6012   unsigned addr = fieldFromInstruction(Val, 0, 7) |
6013                   (fieldFromInstruction(Val, 23, 1) << 7) | (Rn << 8);
6014 
6015   if (Writeback) {
6016     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
6017       return MCDisassembler::Fail;
6018   }
6019   if (!Check(S, DecodeT2AddrModeImm7s4(Inst, addr, Address, Decoder)))
6020     return MCDisassembler::Fail;
6021 
6022   Inst.addOperand(MCOperand::createImm(ARMCC::AL));
6023   Inst.addOperand(MCOperand::createReg(0));
6024 
6025   return S;
6026 }
6027 
6028 static DecodeStatus DecodeMVEOverlappingLongShift(
6029   MCInst &Inst, unsigned Insn, uint64_t Address, const void *Decoder) {
6030   DecodeStatus S = MCDisassembler::Success;
6031 
6032   unsigned RdaLo = fieldFromInstruction(Insn, 17, 3) << 1;
6033   unsigned RdaHi = fieldFromInstruction(Insn, 9, 3) << 1;
6034   unsigned Rm = fieldFromInstruction(Insn, 12, 4);
6035 
6036   if (RdaHi == 14) {
6037     // This value of RdaHi (really indicating pc, because RdaHi has to
6038     // be an odd-numbered register, so the low bit will be set by the
6039     // decode function below) indicates that we must decode as SQRSHR
6040     // or UQRSHL, which both have a single Rda register field with all
6041     // four bits.
6042     unsigned Rda = fieldFromInstruction(Insn, 16, 4);
6043 
6044     switch (Inst.getOpcode()) {
6045       case ARM::MVE_ASRLr:
6046       case ARM::MVE_SQRSHRL:
6047         Inst.setOpcode(ARM::MVE_SQRSHR);
6048         break;
6049       case ARM::MVE_LSLLr:
6050       case ARM::MVE_UQRSHLL:
6051         Inst.setOpcode(ARM::MVE_UQRSHL);
6052         break;
6053       default:
6054         llvm_unreachable("Unexpected starting opcode!");
6055     }
6056 
6057     // Rda as output parameter
6058     if (!Check(S, DecoderGPRRegisterClass(Inst, Rda, Address, Decoder)))
6059       return MCDisassembler::Fail;
6060 
6061     // Rda again as input parameter
6062     if (!Check(S, DecoderGPRRegisterClass(Inst, Rda, Address, Decoder)))
6063       return MCDisassembler::Fail;
6064 
6065     // Rm, the amount to shift by
6066     if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
6067       return MCDisassembler::Fail;
6068 
6069     return S;
6070   }
6071 
6072   // Otherwise, we decode as whichever opcode our caller has already
6073   // put into Inst. Those all look the same:
6074 
6075   // RdaLo,RdaHi as output parameters
6076   if (!Check(S, DecodetGPREvenRegisterClass(Inst, RdaLo, Address, Decoder)))
6077     return MCDisassembler::Fail;
6078   if (!Check(S, DecodetGPROddRegisterClass(Inst, RdaHi, Address, Decoder)))
6079     return MCDisassembler::Fail;
6080 
6081   // RdaLo,RdaHi again as input parameters
6082   if (!Check(S, DecodetGPREvenRegisterClass(Inst, RdaLo, Address, Decoder)))
6083     return MCDisassembler::Fail;
6084   if (!Check(S, DecodetGPROddRegisterClass(Inst, RdaHi, Address, Decoder)))
6085     return MCDisassembler::Fail;
6086 
6087   // Rm, the amount to shift by
6088   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
6089     return MCDisassembler::Fail;
6090 
6091   return S;
6092 }
6093