xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision 2946cd701067404b99c39fb29dc9c74bd7193eb3)
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 "MCTargetDesc/ARMAddressingModes.h"
10 #include "MCTargetDesc/ARMBaseInfo.h"
11 #include "MCTargetDesc/ARMMCTargetDesc.h"
12 #include "Utils/ARMBaseInfo.h"
13 #include "llvm/MC/MCContext.h"
14 #include "llvm/MC/MCDisassembler/MCDisassembler.h"
15 #include "llvm/MC/MCFixedLenDisassembler.h"
16 #include "llvm/MC/MCInst.h"
17 #include "llvm/MC/MCInstrDesc.h"
18 #include "llvm/MC/MCSubtargetInfo.h"
19 #include "llvm/MC/SubtargetFeature.h"
20 #include "llvm/Support/Compiler.h"
21 #include "llvm/Support/ErrorHandling.h"
22 #include "llvm/Support/MathExtras.h"
23 #include "llvm/Support/TargetRegistry.h"
24 #include "llvm/Support/raw_ostream.h"
25 #include <algorithm>
26 #include <cassert>
27 #include <cstdint>
28 #include <vector>
29 
30 using namespace llvm;
31 
32 #define DEBUG_TYPE "arm-disassembler"
33 
34 using DecodeStatus = MCDisassembler::DecodeStatus;
35 
36 namespace {
37 
38   // Handles the condition code status of instructions in IT blocks
39   class ITStatus
40   {
41     public:
42       // Returns the condition code for instruction in IT block
43       unsigned getITCC() {
44         unsigned CC = ARMCC::AL;
45         if (instrInITBlock())
46           CC = ITStates.back();
47         return CC;
48       }
49 
50       // Advances the IT block state to the next T or E
51       void advanceITState() {
52         ITStates.pop_back();
53       }
54 
55       // Returns true if the current instruction is in an IT block
56       bool instrInITBlock() {
57         return !ITStates.empty();
58       }
59 
60       // Returns true if current instruction is the last instruction in an IT block
61       bool instrLastInITBlock() {
62         return ITStates.size() == 1;
63       }
64 
65       // Called when decoding an IT instruction. Sets the IT state for the following
66       // instructions that for the IT block. Firstcond and Mask correspond to the
67       // fields in the IT instruction encoding.
68       void setITState(char Firstcond, char Mask) {
69         // (3 - the number of trailing zeros) is the number of then / else.
70         unsigned CondBit0 = Firstcond & 1;
71         unsigned NumTZ = countTrailingZeros<uint8_t>(Mask);
72         unsigned char CCBits = static_cast<unsigned char>(Firstcond & 0xf);
73         assert(NumTZ <= 3 && "Invalid IT mask!");
74         // push condition codes onto the stack the correct order for the pops
75         for (unsigned Pos = NumTZ+1; Pos <= 3; ++Pos) {
76           bool T = ((Mask >> Pos) & 1) == CondBit0;
77           if (T)
78             ITStates.push_back(CCBits);
79           else
80             ITStates.push_back(CCBits ^ 1);
81         }
82         ITStates.push_back(CCBits);
83       }
84 
85     private:
86       std::vector<unsigned char> ITStates;
87   };
88 
89 /// ARM disassembler for all ARM platforms.
90 class ARMDisassembler : public MCDisassembler {
91 public:
92   ARMDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx) :
93     MCDisassembler(STI, Ctx) {
94   }
95 
96   ~ARMDisassembler() override = default;
97 
98   DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
99                               ArrayRef<uint8_t> Bytes, uint64_t Address,
100                               raw_ostream &VStream,
101                               raw_ostream &CStream) const override;
102 };
103 
104 /// Thumb disassembler for all Thumb platforms.
105 class ThumbDisassembler : public MCDisassembler {
106 public:
107   ThumbDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx) :
108     MCDisassembler(STI, Ctx) {
109   }
110 
111   ~ThumbDisassembler() override = default;
112 
113   DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
114                               ArrayRef<uint8_t> Bytes, uint64_t Address,
115                               raw_ostream &VStream,
116                               raw_ostream &CStream) const override;
117 
118 private:
119   mutable ITStatus ITBlock;
120 
121   DecodeStatus AddThumbPredicate(MCInst&) const;
122   void UpdateThumbVFPPredicate(MCInst&) const;
123 };
124 
125 } // end anonymous namespace
126 
127 static bool Check(DecodeStatus &Out, DecodeStatus In) {
128   switch (In) {
129     case MCDisassembler::Success:
130       // Out stays the same.
131       return true;
132     case MCDisassembler::SoftFail:
133       Out = In;
134       return true;
135     case MCDisassembler::Fail:
136       Out = In;
137       return false;
138   }
139   llvm_unreachable("Invalid DecodeStatus!");
140 }
141 
142 // Forward declare these because the autogenerated code will reference them.
143 // Definitions are further down.
144 static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
145                                    uint64_t Address, const void *Decoder);
146 static DecodeStatus DecodeGPRnopcRegisterClass(MCInst &Inst,
147                                                unsigned RegNo, uint64_t Address,
148                                                const void *Decoder);
149 static DecodeStatus DecodeGPRwithAPSRRegisterClass(MCInst &Inst,
150                                                unsigned RegNo, uint64_t Address,
151                                                const void *Decoder);
152 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
153                                    uint64_t Address, const void *Decoder);
154 static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
155                                    uint64_t Address, const void *Decoder);
156 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
157                                    uint64_t Address, const void *Decoder);
158 static DecodeStatus DecodeGPRPairRegisterClass(MCInst &Inst, unsigned RegNo,
159                                    uint64_t Address, const void *Decoder);
160 static DecodeStatus DecodeHPRRegisterClass(MCInst &Inst, unsigned RegNo,
161                                    uint64_t Address, const void *Decoder);
162 static DecodeStatus DecodeSPRRegisterClass(MCInst &Inst, unsigned RegNo,
163                                    uint64_t Address, const void *Decoder);
164 static DecodeStatus DecodeDPRRegisterClass(MCInst &Inst, unsigned RegNo,
165                                    uint64_t Address, const void *Decoder);
166 static DecodeStatus DecodeDPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
167                                    uint64_t Address, const void *Decoder);
168 static DecodeStatus DecodeDPR_VFP2RegisterClass(MCInst &Inst,
169                                                 unsigned RegNo,
170                                                 uint64_t Address,
171                                                 const void *Decoder);
172 static DecodeStatus DecodeQPRRegisterClass(MCInst &Inst, unsigned RegNo,
173                                    uint64_t Address, const void *Decoder);
174 static DecodeStatus DecodeDPairRegisterClass(MCInst &Inst, unsigned RegNo,
175                                    uint64_t Address, const void *Decoder);
176 static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst &Inst,
177                                unsigned RegNo, uint64_t Address,
178                                const void *Decoder);
179 
180 static DecodeStatus DecodePredicateOperand(MCInst &Inst, unsigned Val,
181                                uint64_t Address, const void *Decoder);
182 static DecodeStatus DecodeCCOutOperand(MCInst &Inst, unsigned Val,
183                                uint64_t Address, const void *Decoder);
184 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
185                                uint64_t Address, const void *Decoder);
186 static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
187                                uint64_t Address, const void *Decoder);
188 static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
189                                uint64_t Address, const void *Decoder);
190 
191 static DecodeStatus DecodeBitfieldMaskOperand(MCInst &Inst, unsigned Insn,
192                                uint64_t Address, const void *Decoder);
193 static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
194                                uint64_t Address, const void *Decoder);
195 static DecodeStatus DecodeAddrMode2IdxInstruction(MCInst &Inst,
196                                                   unsigned Insn,
197                                                   uint64_t Address,
198                                                   const void *Decoder);
199 static DecodeStatus DecodeSORegMemOperand(MCInst &Inst, unsigned Insn,
200                                uint64_t Address, const void *Decoder);
201 static DecodeStatus DecodeAddrMode3Instruction(MCInst &Inst,unsigned Insn,
202                                uint64_t Address, const void *Decoder);
203 static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Insn,
204                                uint64_t Address, const void *Decoder);
205 static DecodeStatus DecodeSORegRegOperand(MCInst &Inst, unsigned Insn,
206                                uint64_t Address, const void *Decoder);
207 
208 static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst & Inst,
209                                                   unsigned Insn,
210                                                   uint64_t Adddress,
211                                                   const void *Decoder);
212 static DecodeStatus DecodeT2MOVTWInstruction(MCInst &Inst, unsigned Insn,
213                                uint64_t Address, const void *Decoder);
214 static DecodeStatus DecodeArmMOVTWInstruction(MCInst &Inst, unsigned Insn,
215                                uint64_t Address, const void *Decoder);
216 static DecodeStatus DecodeSMLAInstruction(MCInst &Inst, unsigned Insn,
217                                uint64_t Address, const void *Decoder);
218 static DecodeStatus DecodeHINTInstruction(MCInst &Inst, unsigned Insn,
219                                uint64_t Address, const void *Decoder);
220 static DecodeStatus DecodeCPSInstruction(MCInst &Inst, unsigned Insn,
221                                uint64_t Address, const void *Decoder);
222 static DecodeStatus DecodeTSTInstruction(MCInst &Inst, unsigned Insn,
223                                uint64_t Address, const void *Decoder);
224 static DecodeStatus DecodeSETPANInstruction(MCInst &Inst, unsigned Insn,
225                                uint64_t Address, const void *Decoder);
226 static DecodeStatus DecodeT2CPSInstruction(MCInst &Inst, unsigned Insn,
227                                uint64_t Address, const void *Decoder);
228 static DecodeStatus DecodeAddrModeImm12Operand(MCInst &Inst, unsigned Val,
229                                uint64_t Address, const void *Decoder);
230 static DecodeStatus DecodeAddrMode5Operand(MCInst &Inst, unsigned Val,
231                                uint64_t Address, const void *Decoder);
232 static DecodeStatus DecodeAddrMode5FP16Operand(MCInst &Inst, unsigned Val,
233                                uint64_t Address, const void *Decoder);
234 static DecodeStatus DecodeAddrMode7Operand(MCInst &Inst, unsigned Val,
235                                uint64_t Address, const void *Decoder);
236 static DecodeStatus DecodeT2BInstruction(MCInst &Inst, unsigned Insn,
237                                uint64_t Address, const void *Decoder);
238 static DecodeStatus DecodeBranchImmInstruction(MCInst &Inst,unsigned Insn,
239                                uint64_t Address, const void *Decoder);
240 static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
241                                uint64_t Address, const void *Decoder);
242 static DecodeStatus DecodeVLDST1Instruction(MCInst &Inst, unsigned Val,
243                                uint64_t Address, const void *Decoder);
244 static DecodeStatus DecodeVLDST2Instruction(MCInst &Inst, unsigned Val,
245                                uint64_t Address, const void *Decoder);
246 static DecodeStatus DecodeVLDST3Instruction(MCInst &Inst, unsigned Val,
247                                uint64_t Address, const void *Decoder);
248 static DecodeStatus DecodeVLDST4Instruction(MCInst &Inst, unsigned Val,
249                                uint64_t Address, const void *Decoder);
250 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Val,
251                                uint64_t Address, const void *Decoder);
252 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Val,
253                                uint64_t Address, const void *Decoder);
254 static DecodeStatus DecodeVLD1DupInstruction(MCInst &Inst, unsigned Val,
255                                uint64_t Address, const void *Decoder);
256 static DecodeStatus DecodeVLD2DupInstruction(MCInst &Inst, unsigned Val,
257                                uint64_t Address, const void *Decoder);
258 static DecodeStatus DecodeVLD3DupInstruction(MCInst &Inst, unsigned Val,
259                                uint64_t Address, const void *Decoder);
260 static DecodeStatus DecodeVLD4DupInstruction(MCInst &Inst, unsigned Val,
261                                uint64_t Address, const void *Decoder);
262 static DecodeStatus DecodeNEONModImmInstruction(MCInst &Inst,unsigned Val,
263                                uint64_t Address, const void *Decoder);
264 static DecodeStatus DecodeVSHLMaxInstruction(MCInst &Inst, unsigned Val,
265                                uint64_t Address, const void *Decoder);
266 static DecodeStatus DecodeShiftRight8Imm(MCInst &Inst, unsigned Val,
267                                uint64_t Address, const void *Decoder);
268 static DecodeStatus DecodeShiftRight16Imm(MCInst &Inst, unsigned Val,
269                                uint64_t Address, const void *Decoder);
270 static DecodeStatus DecodeShiftRight32Imm(MCInst &Inst, unsigned Val,
271                                uint64_t Address, const void *Decoder);
272 static DecodeStatus DecodeShiftRight64Imm(MCInst &Inst, unsigned Val,
273                                uint64_t Address, const void *Decoder);
274 static DecodeStatus DecodeTBLInstruction(MCInst &Inst, unsigned Insn,
275                                uint64_t Address, const void *Decoder);
276 static DecodeStatus DecodePostIdxReg(MCInst &Inst, unsigned Insn,
277                                uint64_t Address, const void *Decoder);
278 static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Insn,
279                                uint64_t Address, const void *Decoder);
280 static DecodeStatus DecodeMemBarrierOption(MCInst &Inst, unsigned Insn,
281                                uint64_t Address, const void *Decoder);
282 static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Insn,
283                                uint64_t Address, const void *Decoder);
284 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Insn,
285                                uint64_t Address, const void *Decoder);
286 static DecodeStatus DecodeBankedReg(MCInst &Inst, unsigned Insn,
287                                uint64_t Address, const void *Decoder);
288 static DecodeStatus DecodeDoubleRegLoad(MCInst &Inst, unsigned Insn,
289                                uint64_t Address, const void *Decoder);
290 static DecodeStatus DecodeDoubleRegStore(MCInst &Inst, unsigned Insn,
291                                uint64_t Address, const void *Decoder);
292 static DecodeStatus DecodeLDRPreImm(MCInst &Inst, unsigned Insn,
293                                uint64_t Address, const void *Decoder);
294 static DecodeStatus DecodeLDRPreReg(MCInst &Inst, unsigned Insn,
295                                uint64_t Address, const void *Decoder);
296 static DecodeStatus DecodeSTRPreImm(MCInst &Inst, unsigned Insn,
297                                uint64_t Address, const void *Decoder);
298 static DecodeStatus DecodeSTRPreReg(MCInst &Inst, unsigned Insn,
299                                uint64_t Address, const void *Decoder);
300 static DecodeStatus DecodeVLD1LN(MCInst &Inst, unsigned Insn,
301                                uint64_t Address, const void *Decoder);
302 static DecodeStatus DecodeVLD2LN(MCInst &Inst, unsigned Insn,
303                                uint64_t Address, const void *Decoder);
304 static DecodeStatus DecodeVLD3LN(MCInst &Inst, unsigned Insn,
305                                uint64_t Address, const void *Decoder);
306 static DecodeStatus DecodeVLD4LN(MCInst &Inst, unsigned Insn,
307                                uint64_t Address, const void *Decoder);
308 static DecodeStatus DecodeVST1LN(MCInst &Inst, unsigned Insn,
309                                uint64_t Address, const void *Decoder);
310 static DecodeStatus DecodeVST2LN(MCInst &Inst, unsigned Insn,
311                                uint64_t Address, const void *Decoder);
312 static DecodeStatus DecodeVST3LN(MCInst &Inst, unsigned Insn,
313                                uint64_t Address, const void *Decoder);
314 static DecodeStatus DecodeVST4LN(MCInst &Inst, unsigned Insn,
315                                uint64_t Address, const void *Decoder);
316 static DecodeStatus DecodeVMOVSRR(MCInst &Inst, unsigned Insn,
317                                uint64_t Address, const void *Decoder);
318 static DecodeStatus DecodeVMOVRRS(MCInst &Inst, unsigned Insn,
319                                uint64_t Address, const void *Decoder);
320 static DecodeStatus DecodeSwap(MCInst &Inst, unsigned Insn,
321                                uint64_t Address, const void *Decoder);
322 static DecodeStatus DecodeVCVTD(MCInst &Inst, unsigned Insn,
323                                 uint64_t Address, const void *Decoder);
324 static DecodeStatus DecodeVCVTQ(MCInst &Inst, unsigned Insn,
325                                 uint64_t Address, const void *Decoder);
326 static DecodeStatus DecodeNEONComplexLane64Instruction(MCInst &Inst,
327                                                        unsigned Val,
328                                                        uint64_t Address,
329                                                        const void *Decoder);
330 
331 static DecodeStatus DecodeThumbAddSpecialReg(MCInst &Inst, uint16_t Insn,
332                                uint64_t Address, const void *Decoder);
333 static DecodeStatus DecodeThumbBROperand(MCInst &Inst, unsigned Val,
334                                uint64_t Address, const void *Decoder);
335 static DecodeStatus DecodeT2BROperand(MCInst &Inst, unsigned Val,
336                                uint64_t Address, const void *Decoder);
337 static DecodeStatus DecodeThumbCmpBROperand(MCInst &Inst, unsigned Val,
338                                uint64_t Address, const void *Decoder);
339 static DecodeStatus DecodeThumbAddrModeRR(MCInst &Inst, unsigned Val,
340                                uint64_t Address, const void *Decoder);
341 static DecodeStatus DecodeThumbAddrModeIS(MCInst &Inst, unsigned Val,
342                                uint64_t Address, const void *Decoder);
343 static DecodeStatus DecodeThumbAddrModePC(MCInst &Inst, unsigned Val,
344                                uint64_t Address, const void *Decoder);
345 static DecodeStatus DecodeThumbAddrModeSP(MCInst &Inst, unsigned Val,
346                                uint64_t Address, const void *Decoder);
347 static DecodeStatus DecodeT2AddrModeSOReg(MCInst &Inst, unsigned Val,
348                                uint64_t Address, const void *Decoder);
349 static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Val,
350                                uint64_t Address, const void *Decoder);
351 static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
352                                uint64_t Address, const void* Decoder);
353 static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
354                                uint64_t Address, const void* Decoder);
355 static DecodeStatus DecodeT2LoadT(MCInst &Inst, unsigned Insn,
356                                uint64_t Address, const void* Decoder);
357 static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
358                                uint64_t Address, const void* Decoder);
359 static DecodeStatus DecodeT2Imm8S4(MCInst &Inst, unsigned Val,
360                                uint64_t Address, const void *Decoder);
361 static DecodeStatus DecodeT2AddrModeImm8s4(MCInst &Inst, unsigned Val,
362                                uint64_t Address, const void *Decoder);
363 static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst &Inst,unsigned Val,
364                                uint64_t Address, const void *Decoder);
365 static DecodeStatus DecodeT2Imm8(MCInst &Inst, unsigned Val,
366                                uint64_t Address, const void *Decoder);
367 static DecodeStatus DecodeT2AddrModeImm8(MCInst &Inst, unsigned Val,
368                                uint64_t Address, const void *Decoder);
369 static DecodeStatus DecodeThumbAddSPImm(MCInst &Inst, uint16_t Val,
370                                uint64_t Address, const void *Decoder);
371 static DecodeStatus DecodeThumbAddSPReg(MCInst &Inst, uint16_t Insn,
372                                 uint64_t Address, const void *Decoder);
373 static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
374                                 uint64_t Address, const void *Decoder);
375 static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
376                                 uint64_t Address, const void *Decoder);
377 static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Insn,
378                                 uint64_t Address, const void *Decoder);
379 static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
380                                 uint64_t Address, const void *Decoder);
381 static DecodeStatus DecodeThumbTableBranch(MCInst &Inst, unsigned Val,
382                                 uint64_t Address, const void *Decoder);
383 static DecodeStatus DecodeThumb2BCCInstruction(MCInst &Inst, unsigned Val,
384                                 uint64_t Address, const void *Decoder);
385 static DecodeStatus DecodeT2SOImm(MCInst &Inst, unsigned Val,
386                                 uint64_t Address, const void *Decoder);
387 static DecodeStatus DecodeThumbBCCTargetOperand(MCInst &Inst,unsigned Val,
388                                 uint64_t Address, const void *Decoder);
389 static DecodeStatus DecodeThumbBLTargetOperand(MCInst &Inst, unsigned Val,
390                                 uint64_t Address, const void *Decoder);
391 static DecodeStatus DecodeIT(MCInst &Inst, unsigned Val,
392                                 uint64_t Address, const void *Decoder);
393 static DecodeStatus DecodeT2LDRDPreInstruction(MCInst &Inst,unsigned Insn,
394                                uint64_t Address, const void *Decoder);
395 static DecodeStatus DecodeT2STRDPreInstruction(MCInst &Inst,unsigned Insn,
396                                uint64_t Address, const void *Decoder);
397 static DecodeStatus DecodeT2Adr(MCInst &Inst, unsigned Val,
398                                 uint64_t Address, const void *Decoder);
399 static DecodeStatus DecodeT2LdStPre(MCInst &Inst, unsigned Val,
400                                 uint64_t Address, const void *Decoder);
401 static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, unsigned Val,
402                                 uint64_t Address, const void *Decoder);
403 
404 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
405                                 uint64_t Address, const void *Decoder);
406 static DecodeStatus DecoderForMRRC2AndMCRR2(MCInst &Inst, unsigned Val,
407                                             uint64_t Address, const void *Decoder);
408 static DecodeStatus DecodeForVMRSandVMSR(MCInst &Inst, unsigned Val,
409                                          uint64_t Address, const void *Decoder);
410 
411 #include "ARMGenDisassemblerTables.inc"
412 
413 static MCDisassembler *createARMDisassembler(const Target &T,
414                                              const MCSubtargetInfo &STI,
415                                              MCContext &Ctx) {
416   return new ARMDisassembler(STI, Ctx);
417 }
418 
419 static MCDisassembler *createThumbDisassembler(const Target &T,
420                                                const MCSubtargetInfo &STI,
421                                                MCContext &Ctx) {
422   return new ThumbDisassembler(STI, Ctx);
423 }
424 
425 // Post-decoding checks
426 static DecodeStatus checkDecodedInstruction(MCInst &MI, uint64_t &Size,
427                                             uint64_t Address, raw_ostream &OS,
428                                             raw_ostream &CS,
429                                             uint32_t Insn,
430                                             DecodeStatus Result) {
431   switch (MI.getOpcode()) {
432     case ARM::HVC: {
433       // HVC is undefined if condition = 0xf otherwise upredictable
434       // if condition != 0xe
435       uint32_t Cond = (Insn >> 28) & 0xF;
436       if (Cond == 0xF)
437         return MCDisassembler::Fail;
438       if (Cond != 0xE)
439         return MCDisassembler::SoftFail;
440       return Result;
441     }
442     default: return Result;
443   }
444 }
445 
446 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
447                                              ArrayRef<uint8_t> Bytes,
448                                              uint64_t Address, raw_ostream &OS,
449                                              raw_ostream &CS) const {
450   CommentStream = &CS;
451 
452   assert(!STI.getFeatureBits()[ARM::ModeThumb] &&
453          "Asked to disassemble an ARM instruction but Subtarget is in Thumb "
454          "mode!");
455 
456   // We want to read exactly 4 bytes of data.
457   if (Bytes.size() < 4) {
458     Size = 0;
459     return MCDisassembler::Fail;
460   }
461 
462   // Encoded as a small-endian 32-bit word in the stream.
463   uint32_t Insn =
464       (Bytes[3] << 24) | (Bytes[2] << 16) | (Bytes[1] << 8) | (Bytes[0] << 0);
465 
466   // Calling the auto-generated decoder function.
467   DecodeStatus Result =
468       decodeInstruction(DecoderTableARM32, MI, Insn, Address, this, STI);
469   if (Result != MCDisassembler::Fail) {
470     Size = 4;
471     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
472   }
473 
474   struct DecodeTable {
475     const uint8_t *P;
476     bool DecodePred;
477   };
478 
479   const DecodeTable Tables[] = {
480       {DecoderTableVFP32, false},      {DecoderTableVFPV832, false},
481       {DecoderTableNEONData32, true},  {DecoderTableNEONLoadStore32, true},
482       {DecoderTableNEONDup32, true},   {DecoderTablev8NEON32, false},
483       {DecoderTablev8Crypto32, false},
484   };
485 
486   for (auto Table : Tables) {
487     Result = decodeInstruction(Table.P, MI, Insn, Address, this, STI);
488     if (Result != MCDisassembler::Fail) {
489       Size = 4;
490       // Add a fake predicate operand, because we share these instruction
491       // definitions with Thumb2 where these instructions are predicable.
492       if (Table.DecodePred && !DecodePredicateOperand(MI, 0xE, Address, this))
493         return MCDisassembler::Fail;
494       return Result;
495     }
496   }
497 
498   Result =
499       decodeInstruction(DecoderTableCoProc32, MI, Insn, Address, this, STI);
500   if (Result != MCDisassembler::Fail) {
501     Size = 4;
502     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
503   }
504 
505   Size = 4;
506   return MCDisassembler::Fail;
507 }
508 
509 namespace llvm {
510 
511 extern const MCInstrDesc ARMInsts[];
512 
513 } // end namespace llvm
514 
515 /// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the
516 /// immediate Value in the MCInst.  The immediate Value has had any PC
517 /// adjustment made by the caller.  If the instruction is a branch instruction
518 /// then isBranch is true, else false.  If the getOpInfo() function was set as
519 /// part of the setupForSymbolicDisassembly() call then that function is called
520 /// to get any symbolic information at the Address for this instruction.  If
521 /// that returns non-zero then the symbolic information it returns is used to
522 /// create an MCExpr and that is added as an operand to the MCInst.  If
523 /// getOpInfo() returns zero and isBranch is true then a symbol look up for
524 /// Value is done and if a symbol is found an MCExpr is created with that, else
525 /// an MCExpr with Value is created.  This function returns true if it adds an
526 /// operand to the MCInst and false otherwise.
527 static bool tryAddingSymbolicOperand(uint64_t Address, int32_t Value,
528                                      bool isBranch, uint64_t InstSize,
529                                      MCInst &MI, const void *Decoder) {
530   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
531   // FIXME: Does it make sense for value to be negative?
532   return Dis->tryAddingSymbolicOperand(MI, (uint32_t)Value, Address, isBranch,
533                                        /* Offset */ 0, InstSize);
534 }
535 
536 /// tryAddingPcLoadReferenceComment - trys to add a comment as to what is being
537 /// referenced by a load instruction with the base register that is the Pc.
538 /// These can often be values in a literal pool near the Address of the
539 /// instruction.  The Address of the instruction and its immediate Value are
540 /// used as a possible literal pool entry.  The SymbolLookUp call back will
541 /// return the name of a symbol referenced by the literal pool's entry if
542 /// the referenced address is that of a symbol.  Or it will return a pointer to
543 /// a literal 'C' string if the referenced address of the literal pool's entry
544 /// is an address into a section with 'C' string literals.
545 static void tryAddingPcLoadReferenceComment(uint64_t Address, int Value,
546                                             const void *Decoder) {
547   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
548   Dis->tryAddingPcLoadReferenceComment(Value, Address);
549 }
550 
551 // Thumb1 instructions don't have explicit S bits.  Rather, they
552 // implicitly set CPSR.  Since it's not represented in the encoding, the
553 // auto-generated decoder won't inject the CPSR operand.  We need to fix
554 // that as a post-pass.
555 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
556   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
557   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
558   MCInst::iterator I = MI.begin();
559   for (unsigned i = 0; i < NumOps; ++i, ++I) {
560     if (I == MI.end()) break;
561     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
562       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
563       MI.insert(I, MCOperand::createReg(InITBlock ? 0 : ARM::CPSR));
564       return;
565     }
566   }
567 
568   MI.insert(I, MCOperand::createReg(InITBlock ? 0 : ARM::CPSR));
569 }
570 
571 // Most Thumb instructions don't have explicit predicates in the
572 // encoding, but rather get their predicates from IT context.  We need
573 // to fix up the predicate operands using this context information as a
574 // post-pass.
575 MCDisassembler::DecodeStatus
576 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
577   MCDisassembler::DecodeStatus S = Success;
578 
579   const FeatureBitset &FeatureBits = getSubtargetInfo().getFeatureBits();
580 
581   // A few instructions actually have predicates encoded in them.  Don't
582   // try to overwrite it if we're seeing one of those.
583   switch (MI.getOpcode()) {
584     case ARM::tBcc:
585     case ARM::t2Bcc:
586     case ARM::tCBZ:
587     case ARM::tCBNZ:
588     case ARM::tCPS:
589     case ARM::t2CPS3p:
590     case ARM::t2CPS2p:
591     case ARM::t2CPS1p:
592     case ARM::tMOVSr:
593     case ARM::tSETEND:
594       // Some instructions (mostly conditional branches) are not
595       // allowed in IT blocks.
596       if (ITBlock.instrInITBlock())
597         S = SoftFail;
598       else
599         return Success;
600       break;
601     case ARM::t2HINT:
602       if (MI.getOperand(0).getImm() == 0x10 && (FeatureBits[ARM::FeatureRAS]) != 0)
603         S = SoftFail;
604       break;
605     case ARM::tB:
606     case ARM::t2B:
607     case ARM::t2TBB:
608     case ARM::t2TBH:
609       // Some instructions (mostly unconditional branches) can
610       // only appears at the end of, or outside of, an IT.
611       if (ITBlock.instrInITBlock() && !ITBlock.instrLastInITBlock())
612         S = SoftFail;
613       break;
614     default:
615       break;
616   }
617 
618   // If we're in an IT block, base the predicate on that.  Otherwise,
619   // assume a predicate of AL.
620   unsigned CC;
621   CC = ITBlock.getITCC();
622   if (CC == 0xF)
623     CC = ARMCC::AL;
624   if (ITBlock.instrInITBlock())
625     ITBlock.advanceITState();
626 
627   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
628   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
629   MCInst::iterator I = MI.begin();
630   for (unsigned i = 0; i < NumOps; ++i, ++I) {
631     if (I == MI.end()) break;
632     if (OpInfo[i].isPredicate()) {
633       I = MI.insert(I, MCOperand::createImm(CC));
634       ++I;
635       if (CC == ARMCC::AL)
636         MI.insert(I, MCOperand::createReg(0));
637       else
638         MI.insert(I, MCOperand::createReg(ARM::CPSR));
639       return S;
640     }
641   }
642 
643   I = MI.insert(I, MCOperand::createImm(CC));
644   ++I;
645   if (CC == ARMCC::AL)
646     MI.insert(I, MCOperand::createReg(0));
647   else
648     MI.insert(I, MCOperand::createReg(ARM::CPSR));
649 
650   return S;
651 }
652 
653 // Thumb VFP instructions are a special case.  Because we share their
654 // encodings between ARM and Thumb modes, and they are predicable in ARM
655 // mode, the auto-generated decoder will give them an (incorrect)
656 // predicate operand.  We need to rewrite these operands based on the IT
657 // context as a post-pass.
658 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
659   unsigned CC;
660   CC = ITBlock.getITCC();
661   if (CC == 0xF)
662     CC = ARMCC::AL;
663   if (ITBlock.instrInITBlock())
664     ITBlock.advanceITState();
665 
666   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
667   MCInst::iterator I = MI.begin();
668   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
669   for (unsigned i = 0; i < NumOps; ++i, ++I) {
670     if (OpInfo[i].isPredicate() ) {
671       I->setImm(CC);
672       ++I;
673       if (CC == ARMCC::AL)
674         I->setReg(0);
675       else
676         I->setReg(ARM::CPSR);
677       return;
678     }
679   }
680 }
681 
682 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
683                                                ArrayRef<uint8_t> Bytes,
684                                                uint64_t Address,
685                                                raw_ostream &OS,
686                                                raw_ostream &CS) const {
687   CommentStream = &CS;
688 
689   assert(STI.getFeatureBits()[ARM::ModeThumb] &&
690          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
691 
692   // We want to read exactly 2 bytes of data.
693   if (Bytes.size() < 2) {
694     Size = 0;
695     return MCDisassembler::Fail;
696   }
697 
698   uint16_t Insn16 = (Bytes[1] << 8) | Bytes[0];
699   DecodeStatus Result =
700       decodeInstruction(DecoderTableThumb16, MI, Insn16, Address, this, STI);
701   if (Result != MCDisassembler::Fail) {
702     Size = 2;
703     Check(Result, AddThumbPredicate(MI));
704     return Result;
705   }
706 
707   Result = decodeInstruction(DecoderTableThumbSBit16, MI, Insn16, Address, this,
708                              STI);
709   if (Result) {
710     Size = 2;
711     bool InITBlock = ITBlock.instrInITBlock();
712     Check(Result, AddThumbPredicate(MI));
713     AddThumb1SBit(MI, InITBlock);
714     return Result;
715   }
716 
717   Result =
718       decodeInstruction(DecoderTableThumb216, MI, Insn16, Address, this, STI);
719   if (Result != MCDisassembler::Fail) {
720     Size = 2;
721 
722     // Nested IT blocks are UNPREDICTABLE.  Must be checked before we add
723     // the Thumb predicate.
724     if (MI.getOpcode() == ARM::t2IT && ITBlock.instrInITBlock())
725       Result = MCDisassembler::SoftFail;
726 
727     Check(Result, AddThumbPredicate(MI));
728 
729     // If we find an IT instruction, we need to parse its condition
730     // code and mask operands so that we can apply them correctly
731     // to the subsequent instructions.
732     if (MI.getOpcode() == ARM::t2IT) {
733       unsigned Firstcond = MI.getOperand(0).getImm();
734       unsigned Mask = MI.getOperand(1).getImm();
735       ITBlock.setITState(Firstcond, Mask);
736 
737       // An IT instruction that would give a 'NV' predicate is unpredictable.
738       if (Firstcond == ARMCC::AL && !isPowerOf2_32(Mask))
739         CS << "unpredictable IT predicate sequence";
740     }
741 
742     return Result;
743   }
744 
745   // We want to read exactly 4 bytes of data.
746   if (Bytes.size() < 4) {
747     Size = 0;
748     return MCDisassembler::Fail;
749   }
750 
751   uint32_t Insn32 =
752       (Bytes[3] << 8) | (Bytes[2] << 0) | (Bytes[1] << 24) | (Bytes[0] << 16);
753   Result =
754       decodeInstruction(DecoderTableThumb32, MI, Insn32, Address, this, STI);
755   if (Result != MCDisassembler::Fail) {
756     Size = 4;
757     bool InITBlock = ITBlock.instrInITBlock();
758     Check(Result, AddThumbPredicate(MI));
759     AddThumb1SBit(MI, InITBlock);
760     return Result;
761   }
762 
763   Result =
764       decodeInstruction(DecoderTableThumb232, MI, Insn32, Address, this, STI);
765   if (Result != MCDisassembler::Fail) {
766     Size = 4;
767     Check(Result, AddThumbPredicate(MI));
768     return Result;
769   }
770 
771   if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
772     Result =
773         decodeInstruction(DecoderTableVFP32, MI, Insn32, Address, this, STI);
774     if (Result != MCDisassembler::Fail) {
775       Size = 4;
776       UpdateThumbVFPPredicate(MI);
777       return Result;
778     }
779   }
780 
781   Result =
782       decodeInstruction(DecoderTableVFPV832, MI, Insn32, Address, this, STI);
783   if (Result != MCDisassembler::Fail) {
784     Size = 4;
785     return Result;
786   }
787 
788   if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
789     Result = decodeInstruction(DecoderTableNEONDup32, MI, Insn32, Address, this,
790                                STI);
791     if (Result != MCDisassembler::Fail) {
792       Size = 4;
793       Check(Result, AddThumbPredicate(MI));
794       return Result;
795     }
796   }
797 
798   if (fieldFromInstruction(Insn32, 24, 8) == 0xF9) {
799     uint32_t NEONLdStInsn = Insn32;
800     NEONLdStInsn &= 0xF0FFFFFF;
801     NEONLdStInsn |= 0x04000000;
802     Result = decodeInstruction(DecoderTableNEONLoadStore32, MI, NEONLdStInsn,
803                                Address, this, STI);
804     if (Result != MCDisassembler::Fail) {
805       Size = 4;
806       Check(Result, AddThumbPredicate(MI));
807       return Result;
808     }
809   }
810 
811   if (fieldFromInstruction(Insn32, 24, 4) == 0xF) {
812     uint32_t NEONDataInsn = Insn32;
813     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
814     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
815     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
816     Result = decodeInstruction(DecoderTableNEONData32, MI, NEONDataInsn,
817                                Address, this, STI);
818     if (Result != MCDisassembler::Fail) {
819       Size = 4;
820       Check(Result, AddThumbPredicate(MI));
821       return Result;
822     }
823 
824     uint32_t NEONCryptoInsn = Insn32;
825     NEONCryptoInsn &= 0xF0FFFFFF; // Clear bits 27-24
826     NEONCryptoInsn |= (NEONCryptoInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
827     NEONCryptoInsn |= 0x12000000; // Set bits 28 and 25
828     Result = decodeInstruction(DecoderTablev8Crypto32, MI, NEONCryptoInsn,
829                                Address, this, STI);
830     if (Result != MCDisassembler::Fail) {
831       Size = 4;
832       return Result;
833     }
834 
835     uint32_t NEONv8Insn = Insn32;
836     NEONv8Insn &= 0xF3FFFFFF; // Clear bits 27-26
837     Result = decodeInstruction(DecoderTablev8NEON32, MI, NEONv8Insn, Address,
838                                this, STI);
839     if (Result != MCDisassembler::Fail) {
840       Size = 4;
841       return Result;
842     }
843   }
844 
845   Result =
846       decodeInstruction(DecoderTableThumb2CoProc32, MI, Insn32, Address, this, STI);
847   if (Result != MCDisassembler::Fail) {
848     Size = 4;
849     Check(Result, AddThumbPredicate(MI));
850     return Result;
851   }
852 
853   Size = 0;
854   return MCDisassembler::Fail;
855 }
856 
857 extern "C" void LLVMInitializeARMDisassembler() {
858   TargetRegistry::RegisterMCDisassembler(getTheARMLETarget(),
859                                          createARMDisassembler);
860   TargetRegistry::RegisterMCDisassembler(getTheARMBETarget(),
861                                          createARMDisassembler);
862   TargetRegistry::RegisterMCDisassembler(getTheThumbLETarget(),
863                                          createThumbDisassembler);
864   TargetRegistry::RegisterMCDisassembler(getTheThumbBETarget(),
865                                          createThumbDisassembler);
866 }
867 
868 static const uint16_t GPRDecoderTable[] = {
869   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
870   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
871   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
872   ARM::R12, ARM::SP, ARM::LR, ARM::PC
873 };
874 
875 static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
876                                    uint64_t Address, const void *Decoder) {
877   if (RegNo > 15)
878     return MCDisassembler::Fail;
879 
880   unsigned Register = GPRDecoderTable[RegNo];
881   Inst.addOperand(MCOperand::createReg(Register));
882   return MCDisassembler::Success;
883 }
884 
885 static DecodeStatus
886 DecodeGPRnopcRegisterClass(MCInst &Inst, unsigned RegNo,
887                            uint64_t Address, const void *Decoder) {
888   DecodeStatus S = MCDisassembler::Success;
889 
890   if (RegNo == 15)
891     S = MCDisassembler::SoftFail;
892 
893   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
894 
895   return S;
896 }
897 
898 static DecodeStatus
899 DecodeGPRwithAPSRRegisterClass(MCInst &Inst, unsigned RegNo,
900                                uint64_t Address, const void *Decoder) {
901   DecodeStatus S = MCDisassembler::Success;
902 
903   if (RegNo == 15)
904   {
905     Inst.addOperand(MCOperand::createReg(ARM::APSR_NZCV));
906     return MCDisassembler::Success;
907   }
908 
909   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
910   return S;
911 }
912 
913 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
914                                    uint64_t Address, const void *Decoder) {
915   if (RegNo > 7)
916     return MCDisassembler::Fail;
917   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
918 }
919 
920 static const uint16_t GPRPairDecoderTable[] = {
921   ARM::R0_R1, ARM::R2_R3,   ARM::R4_R5,  ARM::R6_R7,
922   ARM::R8_R9, ARM::R10_R11, ARM::R12_SP
923 };
924 
925 static DecodeStatus DecodeGPRPairRegisterClass(MCInst &Inst, unsigned RegNo,
926                                    uint64_t Address, const void *Decoder) {
927   DecodeStatus S = MCDisassembler::Success;
928 
929   if (RegNo > 13)
930     return MCDisassembler::Fail;
931 
932   if ((RegNo & 1) || RegNo == 0xe)
933      S = MCDisassembler::SoftFail;
934 
935   unsigned RegisterPair = GPRPairDecoderTable[RegNo/2];
936   Inst.addOperand(MCOperand::createReg(RegisterPair));
937   return S;
938 }
939 
940 static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
941                                    uint64_t Address, const void *Decoder) {
942   unsigned Register = 0;
943   switch (RegNo) {
944     case 0:
945       Register = ARM::R0;
946       break;
947     case 1:
948       Register = ARM::R1;
949       break;
950     case 2:
951       Register = ARM::R2;
952       break;
953     case 3:
954       Register = ARM::R3;
955       break;
956     case 9:
957       Register = ARM::R9;
958       break;
959     case 12:
960       Register = ARM::R12;
961       break;
962     default:
963       return MCDisassembler::Fail;
964     }
965 
966   Inst.addOperand(MCOperand::createReg(Register));
967   return MCDisassembler::Success;
968 }
969 
970 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
971                                    uint64_t Address, const void *Decoder) {
972   DecodeStatus S = MCDisassembler::Success;
973 
974   const FeatureBitset &featureBits =
975     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
976 
977   if ((RegNo == 13 && !featureBits[ARM::HasV8Ops]) || RegNo == 15)
978     S = MCDisassembler::SoftFail;
979 
980   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
981   return S;
982 }
983 
984 static const uint16_t SPRDecoderTable[] = {
985      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
986      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
987      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
988     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
989     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
990     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
991     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
992     ARM::S28, ARM::S29, ARM::S30, ARM::S31
993 };
994 
995 static DecodeStatus DecodeSPRRegisterClass(MCInst &Inst, unsigned RegNo,
996                                    uint64_t Address, const void *Decoder) {
997   if (RegNo > 31)
998     return MCDisassembler::Fail;
999 
1000   unsigned Register = SPRDecoderTable[RegNo];
1001   Inst.addOperand(MCOperand::createReg(Register));
1002   return MCDisassembler::Success;
1003 }
1004 
1005 static DecodeStatus DecodeHPRRegisterClass(MCInst &Inst, unsigned RegNo,
1006                                    uint64_t Address, const void *Decoder) {
1007   return DecodeSPRRegisterClass(Inst, RegNo, Address, Decoder);
1008 }
1009 
1010 static const uint16_t DPRDecoderTable[] = {
1011      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
1012      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
1013      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
1014     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
1015     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
1016     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
1017     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
1018     ARM::D28, ARM::D29, ARM::D30, ARM::D31
1019 };
1020 
1021 static DecodeStatus DecodeDPRRegisterClass(MCInst &Inst, unsigned RegNo,
1022                                    uint64_t Address, const void *Decoder) {
1023   const FeatureBitset &featureBits =
1024     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
1025 
1026   bool hasD16 = featureBits[ARM::FeatureD16];
1027 
1028   if (RegNo > 31 || (hasD16 && RegNo > 15))
1029     return MCDisassembler::Fail;
1030 
1031   unsigned Register = DPRDecoderTable[RegNo];
1032   Inst.addOperand(MCOperand::createReg(Register));
1033   return MCDisassembler::Success;
1034 }
1035 
1036 static DecodeStatus DecodeDPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
1037                                    uint64_t Address, const void *Decoder) {
1038   if (RegNo > 7)
1039     return MCDisassembler::Fail;
1040   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
1041 }
1042 
1043 static DecodeStatus
1044 DecodeDPR_VFP2RegisterClass(MCInst &Inst, unsigned RegNo,
1045                             uint64_t Address, const void *Decoder) {
1046   if (RegNo > 15)
1047     return MCDisassembler::Fail;
1048   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
1049 }
1050 
1051 static const uint16_t QPRDecoderTable[] = {
1052      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
1053      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
1054      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
1055     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
1056 };
1057 
1058 static DecodeStatus DecodeQPRRegisterClass(MCInst &Inst, unsigned RegNo,
1059                                    uint64_t Address, const void *Decoder) {
1060   if (RegNo > 31 || (RegNo & 1) != 0)
1061     return MCDisassembler::Fail;
1062   RegNo >>= 1;
1063 
1064   unsigned Register = QPRDecoderTable[RegNo];
1065   Inst.addOperand(MCOperand::createReg(Register));
1066   return MCDisassembler::Success;
1067 }
1068 
1069 static const uint16_t DPairDecoderTable[] = {
1070   ARM::Q0,  ARM::D1_D2,   ARM::Q1,  ARM::D3_D4,   ARM::Q2,  ARM::D5_D6,
1071   ARM::Q3,  ARM::D7_D8,   ARM::Q4,  ARM::D9_D10,  ARM::Q5,  ARM::D11_D12,
1072   ARM::Q6,  ARM::D13_D14, ARM::Q7,  ARM::D15_D16, ARM::Q8,  ARM::D17_D18,
1073   ARM::Q9,  ARM::D19_D20, ARM::Q10, ARM::D21_D22, ARM::Q11, ARM::D23_D24,
1074   ARM::Q12, ARM::D25_D26, ARM::Q13, ARM::D27_D28, ARM::Q14, ARM::D29_D30,
1075   ARM::Q15
1076 };
1077 
1078 static DecodeStatus DecodeDPairRegisterClass(MCInst &Inst, unsigned RegNo,
1079                                    uint64_t Address, const void *Decoder) {
1080   if (RegNo > 30)
1081     return MCDisassembler::Fail;
1082 
1083   unsigned Register = DPairDecoderTable[RegNo];
1084   Inst.addOperand(MCOperand::createReg(Register));
1085   return MCDisassembler::Success;
1086 }
1087 
1088 static const uint16_t DPairSpacedDecoderTable[] = {
1089   ARM::D0_D2,   ARM::D1_D3,   ARM::D2_D4,   ARM::D3_D5,
1090   ARM::D4_D6,   ARM::D5_D7,   ARM::D6_D8,   ARM::D7_D9,
1091   ARM::D8_D10,  ARM::D9_D11,  ARM::D10_D12, ARM::D11_D13,
1092   ARM::D12_D14, ARM::D13_D15, ARM::D14_D16, ARM::D15_D17,
1093   ARM::D16_D18, ARM::D17_D19, ARM::D18_D20, ARM::D19_D21,
1094   ARM::D20_D22, ARM::D21_D23, ARM::D22_D24, ARM::D23_D25,
1095   ARM::D24_D26, ARM::D25_D27, ARM::D26_D28, ARM::D27_D29,
1096   ARM::D28_D30, ARM::D29_D31
1097 };
1098 
1099 static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst &Inst,
1100                                                    unsigned RegNo,
1101                                                    uint64_t Address,
1102                                                    const void *Decoder) {
1103   if (RegNo > 29)
1104     return MCDisassembler::Fail;
1105 
1106   unsigned Register = DPairSpacedDecoderTable[RegNo];
1107   Inst.addOperand(MCOperand::createReg(Register));
1108   return MCDisassembler::Success;
1109 }
1110 
1111 static DecodeStatus DecodePredicateOperand(MCInst &Inst, unsigned Val,
1112                                uint64_t Address, const void *Decoder) {
1113   if (Val == 0xF) return MCDisassembler::Fail;
1114   // AL predicate is not allowed on Thumb1 branches.
1115   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
1116     return MCDisassembler::Fail;
1117   Inst.addOperand(MCOperand::createImm(Val));
1118   if (Val == ARMCC::AL) {
1119     Inst.addOperand(MCOperand::createReg(0));
1120   } else
1121     Inst.addOperand(MCOperand::createReg(ARM::CPSR));
1122   return MCDisassembler::Success;
1123 }
1124 
1125 static DecodeStatus DecodeCCOutOperand(MCInst &Inst, unsigned Val,
1126                                uint64_t Address, const void *Decoder) {
1127   if (Val)
1128     Inst.addOperand(MCOperand::createReg(ARM::CPSR));
1129   else
1130     Inst.addOperand(MCOperand::createReg(0));
1131   return MCDisassembler::Success;
1132 }
1133 
1134 static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Val,
1135                                uint64_t Address, const void *Decoder) {
1136   DecodeStatus S = MCDisassembler::Success;
1137 
1138   unsigned Rm = fieldFromInstruction(Val, 0, 4);
1139   unsigned type = fieldFromInstruction(Val, 5, 2);
1140   unsigned imm = fieldFromInstruction(Val, 7, 5);
1141 
1142   // Register-immediate
1143   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
1144     return MCDisassembler::Fail;
1145 
1146   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1147   switch (type) {
1148     case 0:
1149       Shift = ARM_AM::lsl;
1150       break;
1151     case 1:
1152       Shift = ARM_AM::lsr;
1153       break;
1154     case 2:
1155       Shift = ARM_AM::asr;
1156       break;
1157     case 3:
1158       Shift = ARM_AM::ror;
1159       break;
1160   }
1161 
1162   if (Shift == ARM_AM::ror && imm == 0)
1163     Shift = ARM_AM::rrx;
1164 
1165   unsigned Op = Shift | (imm << 3);
1166   Inst.addOperand(MCOperand::createImm(Op));
1167 
1168   return S;
1169 }
1170 
1171 static DecodeStatus DecodeSORegRegOperand(MCInst &Inst, unsigned Val,
1172                                uint64_t Address, const void *Decoder) {
1173   DecodeStatus S = MCDisassembler::Success;
1174 
1175   unsigned Rm = fieldFromInstruction(Val, 0, 4);
1176   unsigned type = fieldFromInstruction(Val, 5, 2);
1177   unsigned Rs = fieldFromInstruction(Val, 8, 4);
1178 
1179   // Register-register
1180   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1181     return MCDisassembler::Fail;
1182   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
1183     return MCDisassembler::Fail;
1184 
1185   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1186   switch (type) {
1187     case 0:
1188       Shift = ARM_AM::lsl;
1189       break;
1190     case 1:
1191       Shift = ARM_AM::lsr;
1192       break;
1193     case 2:
1194       Shift = ARM_AM::asr;
1195       break;
1196     case 3:
1197       Shift = ARM_AM::ror;
1198       break;
1199   }
1200 
1201   Inst.addOperand(MCOperand::createImm(Shift));
1202 
1203   return S;
1204 }
1205 
1206 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
1207                                  uint64_t Address, const void *Decoder) {
1208   DecodeStatus S = MCDisassembler::Success;
1209 
1210   bool NeedDisjointWriteback = false;
1211   unsigned WritebackReg = 0;
1212   switch (Inst.getOpcode()) {
1213   default:
1214     break;
1215   case ARM::LDMIA_UPD:
1216   case ARM::LDMDB_UPD:
1217   case ARM::LDMIB_UPD:
1218   case ARM::LDMDA_UPD:
1219   case ARM::t2LDMIA_UPD:
1220   case ARM::t2LDMDB_UPD:
1221   case ARM::t2STMIA_UPD:
1222   case ARM::t2STMDB_UPD:
1223     NeedDisjointWriteback = true;
1224     WritebackReg = Inst.getOperand(0).getReg();
1225     break;
1226   }
1227 
1228   // Empty register lists are not allowed.
1229   if (Val == 0) return MCDisassembler::Fail;
1230   for (unsigned i = 0; i < 16; ++i) {
1231     if (Val & (1 << i)) {
1232       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
1233         return MCDisassembler::Fail;
1234       // Writeback not allowed if Rn is in the target list.
1235       if (NeedDisjointWriteback && WritebackReg == Inst.end()[-1].getReg())
1236         Check(S, MCDisassembler::SoftFail);
1237     }
1238   }
1239 
1240   return S;
1241 }
1242 
1243 static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
1244                                  uint64_t Address, const void *Decoder) {
1245   DecodeStatus S = MCDisassembler::Success;
1246 
1247   unsigned Vd = fieldFromInstruction(Val, 8, 5);
1248   unsigned regs = fieldFromInstruction(Val, 0, 8);
1249 
1250   // In case of unpredictable encoding, tweak the operands.
1251   if (regs == 0 || (Vd + regs) > 32) {
1252     regs = Vd + regs > 32 ? 32 - Vd : regs;
1253     regs = std::max( 1u, regs);
1254     S = MCDisassembler::SoftFail;
1255   }
1256 
1257   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
1258     return MCDisassembler::Fail;
1259   for (unsigned i = 0; i < (regs - 1); ++i) {
1260     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1261       return MCDisassembler::Fail;
1262   }
1263 
1264   return S;
1265 }
1266 
1267 static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
1268                                  uint64_t Address, const void *Decoder) {
1269   DecodeStatus S = MCDisassembler::Success;
1270 
1271   unsigned Vd = fieldFromInstruction(Val, 8, 5);
1272   unsigned regs = fieldFromInstruction(Val, 1, 7);
1273 
1274   // In case of unpredictable encoding, tweak the operands.
1275   if (regs == 0 || regs > 16 || (Vd + regs) > 32) {
1276     regs = Vd + regs > 32 ? 32 - Vd : regs;
1277     regs = std::max( 1u, regs);
1278     regs = std::min(16u, regs);
1279     S = MCDisassembler::SoftFail;
1280   }
1281 
1282   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
1283       return MCDisassembler::Fail;
1284   for (unsigned i = 0; i < (regs - 1); ++i) {
1285     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1286       return MCDisassembler::Fail;
1287   }
1288 
1289   return S;
1290 }
1291 
1292 static DecodeStatus DecodeBitfieldMaskOperand(MCInst &Inst, unsigned Val,
1293                                       uint64_t Address, const void *Decoder) {
1294   // This operand encodes a mask of contiguous zeros between a specified MSB
1295   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
1296   // the mask of all bits LSB-and-lower, and then xor them to create
1297   // the mask of that's all ones on [msb, lsb].  Finally we not it to
1298   // create the final mask.
1299   unsigned msb = fieldFromInstruction(Val, 5, 5);
1300   unsigned lsb = fieldFromInstruction(Val, 0, 5);
1301 
1302   DecodeStatus S = MCDisassembler::Success;
1303   if (lsb > msb) {
1304     Check(S, MCDisassembler::SoftFail);
1305     // The check above will cause the warning for the "potentially undefined
1306     // instruction encoding" but we can't build a bad MCOperand value here
1307     // with a lsb > msb or else printing the MCInst will cause a crash.
1308     lsb = msb;
1309   }
1310 
1311   uint32_t msb_mask = 0xFFFFFFFF;
1312   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;
1313   uint32_t lsb_mask = (1U << lsb) - 1;
1314 
1315   Inst.addOperand(MCOperand::createImm(~(msb_mask ^ lsb_mask)));
1316   return S;
1317 }
1318 
1319 static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
1320                                   uint64_t Address, const void *Decoder) {
1321   DecodeStatus S = MCDisassembler::Success;
1322 
1323   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1324   unsigned CRd = fieldFromInstruction(Insn, 12, 4);
1325   unsigned coproc = fieldFromInstruction(Insn, 8, 4);
1326   unsigned imm = fieldFromInstruction(Insn, 0, 8);
1327   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1328   unsigned U = fieldFromInstruction(Insn, 23, 1);
1329 
1330   switch (Inst.getOpcode()) {
1331     case ARM::LDC_OFFSET:
1332     case ARM::LDC_PRE:
1333     case ARM::LDC_POST:
1334     case ARM::LDC_OPTION:
1335     case ARM::LDCL_OFFSET:
1336     case ARM::LDCL_PRE:
1337     case ARM::LDCL_POST:
1338     case ARM::LDCL_OPTION:
1339     case ARM::STC_OFFSET:
1340     case ARM::STC_PRE:
1341     case ARM::STC_POST:
1342     case ARM::STC_OPTION:
1343     case ARM::STCL_OFFSET:
1344     case ARM::STCL_PRE:
1345     case ARM::STCL_POST:
1346     case ARM::STCL_OPTION:
1347     case ARM::t2LDC_OFFSET:
1348     case ARM::t2LDC_PRE:
1349     case ARM::t2LDC_POST:
1350     case ARM::t2LDC_OPTION:
1351     case ARM::t2LDCL_OFFSET:
1352     case ARM::t2LDCL_PRE:
1353     case ARM::t2LDCL_POST:
1354     case ARM::t2LDCL_OPTION:
1355     case ARM::t2STC_OFFSET:
1356     case ARM::t2STC_PRE:
1357     case ARM::t2STC_POST:
1358     case ARM::t2STC_OPTION:
1359     case ARM::t2STCL_OFFSET:
1360     case ARM::t2STCL_PRE:
1361     case ARM::t2STCL_POST:
1362     case ARM::t2STCL_OPTION:
1363       if (coproc == 0xA || coproc == 0xB)
1364         return MCDisassembler::Fail;
1365       break;
1366     default:
1367       break;
1368   }
1369 
1370   const FeatureBitset &featureBits =
1371     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
1372   if (featureBits[ARM::HasV8Ops] && (coproc != 14))
1373     return MCDisassembler::Fail;
1374 
1375   Inst.addOperand(MCOperand::createImm(coproc));
1376   Inst.addOperand(MCOperand::createImm(CRd));
1377   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1378     return MCDisassembler::Fail;
1379 
1380   switch (Inst.getOpcode()) {
1381     case ARM::t2LDC2_OFFSET:
1382     case ARM::t2LDC2L_OFFSET:
1383     case ARM::t2LDC2_PRE:
1384     case ARM::t2LDC2L_PRE:
1385     case ARM::t2STC2_OFFSET:
1386     case ARM::t2STC2L_OFFSET:
1387     case ARM::t2STC2_PRE:
1388     case ARM::t2STC2L_PRE:
1389     case ARM::LDC2_OFFSET:
1390     case ARM::LDC2L_OFFSET:
1391     case ARM::LDC2_PRE:
1392     case ARM::LDC2L_PRE:
1393     case ARM::STC2_OFFSET:
1394     case ARM::STC2L_OFFSET:
1395     case ARM::STC2_PRE:
1396     case ARM::STC2L_PRE:
1397     case ARM::t2LDC_OFFSET:
1398     case ARM::t2LDCL_OFFSET:
1399     case ARM::t2LDC_PRE:
1400     case ARM::t2LDCL_PRE:
1401     case ARM::t2STC_OFFSET:
1402     case ARM::t2STCL_OFFSET:
1403     case ARM::t2STC_PRE:
1404     case ARM::t2STCL_PRE:
1405     case ARM::LDC_OFFSET:
1406     case ARM::LDCL_OFFSET:
1407     case ARM::LDC_PRE:
1408     case ARM::LDCL_PRE:
1409     case ARM::STC_OFFSET:
1410     case ARM::STCL_OFFSET:
1411     case ARM::STC_PRE:
1412     case ARM::STCL_PRE:
1413       imm = ARM_AM::getAM5Opc(U ? ARM_AM::add : ARM_AM::sub, imm);
1414       Inst.addOperand(MCOperand::createImm(imm));
1415       break;
1416     case ARM::t2LDC2_POST:
1417     case ARM::t2LDC2L_POST:
1418     case ARM::t2STC2_POST:
1419     case ARM::t2STC2L_POST:
1420     case ARM::LDC2_POST:
1421     case ARM::LDC2L_POST:
1422     case ARM::STC2_POST:
1423     case ARM::STC2L_POST:
1424     case ARM::t2LDC_POST:
1425     case ARM::t2LDCL_POST:
1426     case ARM::t2STC_POST:
1427     case ARM::t2STCL_POST:
1428     case ARM::LDC_POST:
1429     case ARM::LDCL_POST:
1430     case ARM::STC_POST:
1431     case ARM::STCL_POST:
1432       imm |= U << 8;
1433       LLVM_FALLTHROUGH;
1434     default:
1435       // The 'option' variant doesn't encode 'U' in the immediate since
1436       // the immediate is unsigned [0,255].
1437       Inst.addOperand(MCOperand::createImm(imm));
1438       break;
1439   }
1440 
1441   switch (Inst.getOpcode()) {
1442     case ARM::LDC_OFFSET:
1443     case ARM::LDC_PRE:
1444     case ARM::LDC_POST:
1445     case ARM::LDC_OPTION:
1446     case ARM::LDCL_OFFSET:
1447     case ARM::LDCL_PRE:
1448     case ARM::LDCL_POST:
1449     case ARM::LDCL_OPTION:
1450     case ARM::STC_OFFSET:
1451     case ARM::STC_PRE:
1452     case ARM::STC_POST:
1453     case ARM::STC_OPTION:
1454     case ARM::STCL_OFFSET:
1455     case ARM::STCL_PRE:
1456     case ARM::STCL_POST:
1457     case ARM::STCL_OPTION:
1458       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1459         return MCDisassembler::Fail;
1460       break;
1461     default:
1462       break;
1463   }
1464 
1465   return S;
1466 }
1467 
1468 static DecodeStatus
1469 DecodeAddrMode2IdxInstruction(MCInst &Inst, unsigned Insn,
1470                               uint64_t Address, const void *Decoder) {
1471   DecodeStatus S = MCDisassembler::Success;
1472 
1473   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1474   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
1475   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1476   unsigned imm = fieldFromInstruction(Insn, 0, 12);
1477   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1478   unsigned reg = fieldFromInstruction(Insn, 25, 1);
1479   unsigned P = fieldFromInstruction(Insn, 24, 1);
1480   unsigned W = fieldFromInstruction(Insn, 21, 1);
1481 
1482   // On stores, the writeback operand precedes Rt.
1483   switch (Inst.getOpcode()) {
1484     case ARM::STR_POST_IMM:
1485     case ARM::STR_POST_REG:
1486     case ARM::STRB_POST_IMM:
1487     case ARM::STRB_POST_REG:
1488     case ARM::STRT_POST_REG:
1489     case ARM::STRT_POST_IMM:
1490     case ARM::STRBT_POST_REG:
1491     case ARM::STRBT_POST_IMM:
1492       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1493         return MCDisassembler::Fail;
1494       break;
1495     default:
1496       break;
1497   }
1498 
1499   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1500     return MCDisassembler::Fail;
1501 
1502   // On loads, the writeback operand comes after Rt.
1503   switch (Inst.getOpcode()) {
1504     case ARM::LDR_POST_IMM:
1505     case ARM::LDR_POST_REG:
1506     case ARM::LDRB_POST_IMM:
1507     case ARM::LDRB_POST_REG:
1508     case ARM::LDRBT_POST_REG:
1509     case ARM::LDRBT_POST_IMM:
1510     case ARM::LDRT_POST_REG:
1511     case ARM::LDRT_POST_IMM:
1512       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1513         return MCDisassembler::Fail;
1514       break;
1515     default:
1516       break;
1517   }
1518 
1519   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1520     return MCDisassembler::Fail;
1521 
1522   ARM_AM::AddrOpc Op = ARM_AM::add;
1523   if (!fieldFromInstruction(Insn, 23, 1))
1524     Op = ARM_AM::sub;
1525 
1526   bool writeback = (P == 0) || (W == 1);
1527   unsigned idx_mode = 0;
1528   if (P && writeback)
1529     idx_mode = ARMII::IndexModePre;
1530   else if (!P && writeback)
1531     idx_mode = ARMII::IndexModePost;
1532 
1533   if (writeback && (Rn == 15 || Rn == Rt))
1534     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1535 
1536   if (reg) {
1537     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1538       return MCDisassembler::Fail;
1539     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1540     switch( fieldFromInstruction(Insn, 5, 2)) {
1541       case 0:
1542         Opc = ARM_AM::lsl;
1543         break;
1544       case 1:
1545         Opc = ARM_AM::lsr;
1546         break;
1547       case 2:
1548         Opc = ARM_AM::asr;
1549         break;
1550       case 3:
1551         Opc = ARM_AM::ror;
1552         break;
1553       default:
1554         return MCDisassembler::Fail;
1555     }
1556     unsigned amt = fieldFromInstruction(Insn, 7, 5);
1557     if (Opc == ARM_AM::ror && amt == 0)
1558       Opc = ARM_AM::rrx;
1559     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1560 
1561     Inst.addOperand(MCOperand::createImm(imm));
1562   } else {
1563     Inst.addOperand(MCOperand::createReg(0));
1564     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1565     Inst.addOperand(MCOperand::createImm(tmp));
1566   }
1567 
1568   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1569     return MCDisassembler::Fail;
1570 
1571   return S;
1572 }
1573 
1574 static DecodeStatus DecodeSORegMemOperand(MCInst &Inst, unsigned Val,
1575                                   uint64_t Address, const void *Decoder) {
1576   DecodeStatus S = MCDisassembler::Success;
1577 
1578   unsigned Rn = fieldFromInstruction(Val, 13, 4);
1579   unsigned Rm = fieldFromInstruction(Val,  0, 4);
1580   unsigned type = fieldFromInstruction(Val, 5, 2);
1581   unsigned imm = fieldFromInstruction(Val, 7, 5);
1582   unsigned U = fieldFromInstruction(Val, 12, 1);
1583 
1584   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1585   switch (type) {
1586     case 0:
1587       ShOp = ARM_AM::lsl;
1588       break;
1589     case 1:
1590       ShOp = ARM_AM::lsr;
1591       break;
1592     case 2:
1593       ShOp = ARM_AM::asr;
1594       break;
1595     case 3:
1596       ShOp = ARM_AM::ror;
1597       break;
1598   }
1599 
1600   if (ShOp == ARM_AM::ror && imm == 0)
1601     ShOp = ARM_AM::rrx;
1602 
1603   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1604     return MCDisassembler::Fail;
1605   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1606     return MCDisassembler::Fail;
1607   unsigned shift;
1608   if (U)
1609     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1610   else
1611     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1612   Inst.addOperand(MCOperand::createImm(shift));
1613 
1614   return S;
1615 }
1616 
1617 static DecodeStatus
1618 DecodeAddrMode3Instruction(MCInst &Inst, unsigned Insn,
1619                            uint64_t Address, const void *Decoder) {
1620   DecodeStatus S = MCDisassembler::Success;
1621 
1622   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
1623   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1624   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1625   unsigned type = fieldFromInstruction(Insn, 22, 1);
1626   unsigned imm = fieldFromInstruction(Insn, 8, 4);
1627   unsigned U = ((~fieldFromInstruction(Insn, 23, 1)) & 1) << 8;
1628   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1629   unsigned W = fieldFromInstruction(Insn, 21, 1);
1630   unsigned P = fieldFromInstruction(Insn, 24, 1);
1631   unsigned Rt2 = Rt + 1;
1632 
1633   bool writeback = (W == 1) | (P == 0);
1634 
1635   // For {LD,ST}RD, Rt must be even, else undefined.
1636   switch (Inst.getOpcode()) {
1637     case ARM::STRD:
1638     case ARM::STRD_PRE:
1639     case ARM::STRD_POST:
1640     case ARM::LDRD:
1641     case ARM::LDRD_PRE:
1642     case ARM::LDRD_POST:
1643       if (Rt & 0x1) S = MCDisassembler::SoftFail;
1644       break;
1645     default:
1646       break;
1647   }
1648   switch (Inst.getOpcode()) {
1649     case ARM::STRD:
1650     case ARM::STRD_PRE:
1651     case ARM::STRD_POST:
1652       if (P == 0 && W == 1)
1653         S = MCDisassembler::SoftFail;
1654 
1655       if (writeback && (Rn == 15 || Rn == Rt || Rn == Rt2))
1656         S = MCDisassembler::SoftFail;
1657       if (type && Rm == 15)
1658         S = MCDisassembler::SoftFail;
1659       if (Rt2 == 15)
1660         S = MCDisassembler::SoftFail;
1661       if (!type && fieldFromInstruction(Insn, 8, 4))
1662         S = MCDisassembler::SoftFail;
1663       break;
1664     case ARM::STRH:
1665     case ARM::STRH_PRE:
1666     case ARM::STRH_POST:
1667       if (Rt == 15)
1668         S = MCDisassembler::SoftFail;
1669       if (writeback && (Rn == 15 || Rn == Rt))
1670         S = MCDisassembler::SoftFail;
1671       if (!type && Rm == 15)
1672         S = MCDisassembler::SoftFail;
1673       break;
1674     case ARM::LDRD:
1675     case ARM::LDRD_PRE:
1676     case ARM::LDRD_POST:
1677       if (type && Rn == 15) {
1678         if (Rt2 == 15)
1679           S = MCDisassembler::SoftFail;
1680         break;
1681       }
1682       if (P == 0 && W == 1)
1683         S = MCDisassembler::SoftFail;
1684       if (!type && (Rt2 == 15 || Rm == 15 || Rm == Rt || Rm == Rt2))
1685         S = MCDisassembler::SoftFail;
1686       if (!type && writeback && Rn == 15)
1687         S = MCDisassembler::SoftFail;
1688       if (writeback && (Rn == Rt || Rn == Rt2))
1689         S = MCDisassembler::SoftFail;
1690       break;
1691     case ARM::LDRH:
1692     case ARM::LDRH_PRE:
1693     case ARM::LDRH_POST:
1694       if (type && Rn == 15) {
1695         if (Rt == 15)
1696           S = MCDisassembler::SoftFail;
1697         break;
1698       }
1699       if (Rt == 15)
1700         S = MCDisassembler::SoftFail;
1701       if (!type && Rm == 15)
1702         S = MCDisassembler::SoftFail;
1703       if (!type && writeback && (Rn == 15 || Rn == Rt))
1704         S = MCDisassembler::SoftFail;
1705       break;
1706     case ARM::LDRSH:
1707     case ARM::LDRSH_PRE:
1708     case ARM::LDRSH_POST:
1709     case ARM::LDRSB:
1710     case ARM::LDRSB_PRE:
1711     case ARM::LDRSB_POST:
1712       if (type && Rn == 15) {
1713         if (Rt == 15)
1714           S = MCDisassembler::SoftFail;
1715         break;
1716       }
1717       if (type && (Rt == 15 || (writeback && Rn == Rt)))
1718         S = MCDisassembler::SoftFail;
1719       if (!type && (Rt == 15 || Rm == 15))
1720         S = MCDisassembler::SoftFail;
1721       if (!type && writeback && (Rn == 15 || Rn == Rt))
1722         S = MCDisassembler::SoftFail;
1723       break;
1724     default:
1725       break;
1726   }
1727 
1728   if (writeback) { // Writeback
1729     if (P)
1730       U |= ARMII::IndexModePre << 9;
1731     else
1732       U |= ARMII::IndexModePost << 9;
1733 
1734     // On stores, the writeback operand precedes Rt.
1735     switch (Inst.getOpcode()) {
1736     case ARM::STRD:
1737     case ARM::STRD_PRE:
1738     case ARM::STRD_POST:
1739     case ARM::STRH:
1740     case ARM::STRH_PRE:
1741     case ARM::STRH_POST:
1742       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1743         return MCDisassembler::Fail;
1744       break;
1745     default:
1746       break;
1747     }
1748   }
1749 
1750   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1751     return MCDisassembler::Fail;
1752   switch (Inst.getOpcode()) {
1753     case ARM::STRD:
1754     case ARM::STRD_PRE:
1755     case ARM::STRD_POST:
1756     case ARM::LDRD:
1757     case ARM::LDRD_PRE:
1758     case ARM::LDRD_POST:
1759       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1760         return MCDisassembler::Fail;
1761       break;
1762     default:
1763       break;
1764   }
1765 
1766   if (writeback) {
1767     // On loads, the writeback operand comes after Rt.
1768     switch (Inst.getOpcode()) {
1769     case ARM::LDRD:
1770     case ARM::LDRD_PRE:
1771     case ARM::LDRD_POST:
1772     case ARM::LDRH:
1773     case ARM::LDRH_PRE:
1774     case ARM::LDRH_POST:
1775     case ARM::LDRSH:
1776     case ARM::LDRSH_PRE:
1777     case ARM::LDRSH_POST:
1778     case ARM::LDRSB:
1779     case ARM::LDRSB_PRE:
1780     case ARM::LDRSB_POST:
1781     case ARM::LDRHTr:
1782     case ARM::LDRSBTr:
1783       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1784         return MCDisassembler::Fail;
1785       break;
1786     default:
1787       break;
1788     }
1789   }
1790 
1791   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1792     return MCDisassembler::Fail;
1793 
1794   if (type) {
1795     Inst.addOperand(MCOperand::createReg(0));
1796     Inst.addOperand(MCOperand::createImm(U | (imm << 4) | Rm));
1797   } else {
1798     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1799     return MCDisassembler::Fail;
1800     Inst.addOperand(MCOperand::createImm(U));
1801   }
1802 
1803   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1804     return MCDisassembler::Fail;
1805 
1806   return S;
1807 }
1808 
1809 static DecodeStatus DecodeRFEInstruction(MCInst &Inst, unsigned Insn,
1810                                  uint64_t Address, const void *Decoder) {
1811   DecodeStatus S = MCDisassembler::Success;
1812 
1813   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1814   unsigned mode = fieldFromInstruction(Insn, 23, 2);
1815 
1816   switch (mode) {
1817     case 0:
1818       mode = ARM_AM::da;
1819       break;
1820     case 1:
1821       mode = ARM_AM::ia;
1822       break;
1823     case 2:
1824       mode = ARM_AM::db;
1825       break;
1826     case 3:
1827       mode = ARM_AM::ib;
1828       break;
1829   }
1830 
1831   Inst.addOperand(MCOperand::createImm(mode));
1832   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1833     return MCDisassembler::Fail;
1834 
1835   return S;
1836 }
1837 
1838 static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
1839                                uint64_t Address, const void *Decoder) {
1840   DecodeStatus S = MCDisassembler::Success;
1841 
1842   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
1843   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1844   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1845   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1846 
1847   if (pred == 0xF)
1848     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1849 
1850   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1851     return MCDisassembler::Fail;
1852   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1853     return MCDisassembler::Fail;
1854   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1855     return MCDisassembler::Fail;
1856   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1857     return MCDisassembler::Fail;
1858   return S;
1859 }
1860 
1861 static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst &Inst,
1862                                   unsigned Insn,
1863                                   uint64_t Address, const void *Decoder) {
1864   DecodeStatus S = MCDisassembler::Success;
1865 
1866   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1867   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1868   unsigned reglist = fieldFromInstruction(Insn, 0, 16);
1869 
1870   if (pred == 0xF) {
1871     // Ambiguous with RFE and SRS
1872     switch (Inst.getOpcode()) {
1873       case ARM::LDMDA:
1874         Inst.setOpcode(ARM::RFEDA);
1875         break;
1876       case ARM::LDMDA_UPD:
1877         Inst.setOpcode(ARM::RFEDA_UPD);
1878         break;
1879       case ARM::LDMDB:
1880         Inst.setOpcode(ARM::RFEDB);
1881         break;
1882       case ARM::LDMDB_UPD:
1883         Inst.setOpcode(ARM::RFEDB_UPD);
1884         break;
1885       case ARM::LDMIA:
1886         Inst.setOpcode(ARM::RFEIA);
1887         break;
1888       case ARM::LDMIA_UPD:
1889         Inst.setOpcode(ARM::RFEIA_UPD);
1890         break;
1891       case ARM::LDMIB:
1892         Inst.setOpcode(ARM::RFEIB);
1893         break;
1894       case ARM::LDMIB_UPD:
1895         Inst.setOpcode(ARM::RFEIB_UPD);
1896         break;
1897       case ARM::STMDA:
1898         Inst.setOpcode(ARM::SRSDA);
1899         break;
1900       case ARM::STMDA_UPD:
1901         Inst.setOpcode(ARM::SRSDA_UPD);
1902         break;
1903       case ARM::STMDB:
1904         Inst.setOpcode(ARM::SRSDB);
1905         break;
1906       case ARM::STMDB_UPD:
1907         Inst.setOpcode(ARM::SRSDB_UPD);
1908         break;
1909       case ARM::STMIA:
1910         Inst.setOpcode(ARM::SRSIA);
1911         break;
1912       case ARM::STMIA_UPD:
1913         Inst.setOpcode(ARM::SRSIA_UPD);
1914         break;
1915       case ARM::STMIB:
1916         Inst.setOpcode(ARM::SRSIB);
1917         break;
1918       case ARM::STMIB_UPD:
1919         Inst.setOpcode(ARM::SRSIB_UPD);
1920         break;
1921       default:
1922         return MCDisassembler::Fail;
1923     }
1924 
1925     // For stores (which become SRS's, the only operand is the mode.
1926     if (fieldFromInstruction(Insn, 20, 1) == 0) {
1927       // Check SRS encoding constraints
1928       if (!(fieldFromInstruction(Insn, 22, 1) == 1 &&
1929             fieldFromInstruction(Insn, 20, 1) == 0))
1930         return MCDisassembler::Fail;
1931 
1932       Inst.addOperand(
1933           MCOperand::createImm(fieldFromInstruction(Insn, 0, 4)));
1934       return S;
1935     }
1936 
1937     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1938   }
1939 
1940   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1941     return MCDisassembler::Fail;
1942   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1943     return MCDisassembler::Fail; // Tied
1944   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1945     return MCDisassembler::Fail;
1946   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1947     return MCDisassembler::Fail;
1948 
1949   return S;
1950 }
1951 
1952 // Check for UNPREDICTABLE predicated ESB instruction
1953 static DecodeStatus DecodeHINTInstruction(MCInst &Inst, unsigned Insn,
1954                                  uint64_t Address, const void *Decoder) {
1955   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1956   unsigned imm8 = fieldFromInstruction(Insn, 0, 8);
1957   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
1958   const FeatureBitset &FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
1959 
1960   DecodeStatus S = MCDisassembler::Success;
1961 
1962   Inst.addOperand(MCOperand::createImm(imm8));
1963 
1964   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1965     return MCDisassembler::Fail;
1966 
1967   // ESB is unpredictable if pred != AL. Without the RAS extension, it is a NOP,
1968   // so all predicates should be allowed.
1969   if (imm8 == 0x10 && pred != 0xe && ((FeatureBits[ARM::FeatureRAS]) != 0))
1970     S = MCDisassembler::SoftFail;
1971 
1972   return S;
1973 }
1974 
1975 static DecodeStatus DecodeCPSInstruction(MCInst &Inst, unsigned Insn,
1976                                  uint64_t Address, const void *Decoder) {
1977   unsigned imod = fieldFromInstruction(Insn, 18, 2);
1978   unsigned M = fieldFromInstruction(Insn, 17, 1);
1979   unsigned iflags = fieldFromInstruction(Insn, 6, 3);
1980   unsigned mode = fieldFromInstruction(Insn, 0, 5);
1981 
1982   DecodeStatus S = MCDisassembler::Success;
1983 
1984   // This decoder is called from multiple location that do not check
1985   // the full encoding is valid before they do.
1986   if (fieldFromInstruction(Insn, 5, 1) != 0 ||
1987       fieldFromInstruction(Insn, 16, 1) != 0 ||
1988       fieldFromInstruction(Insn, 20, 8) != 0x10)
1989     return MCDisassembler::Fail;
1990 
1991   // imod == '01' --> UNPREDICTABLE
1992   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
1993   // return failure here.  The '01' imod value is unprintable, so there's
1994   // nothing useful we could do even if we returned UNPREDICTABLE.
1995 
1996   if (imod == 1) return MCDisassembler::Fail;
1997 
1998   if (imod && M) {
1999     Inst.setOpcode(ARM::CPS3p);
2000     Inst.addOperand(MCOperand::createImm(imod));
2001     Inst.addOperand(MCOperand::createImm(iflags));
2002     Inst.addOperand(MCOperand::createImm(mode));
2003   } else if (imod && !M) {
2004     Inst.setOpcode(ARM::CPS2p);
2005     Inst.addOperand(MCOperand::createImm(imod));
2006     Inst.addOperand(MCOperand::createImm(iflags));
2007     if (mode) S = MCDisassembler::SoftFail;
2008   } else if (!imod && M) {
2009     Inst.setOpcode(ARM::CPS1p);
2010     Inst.addOperand(MCOperand::createImm(mode));
2011     if (iflags) S = MCDisassembler::SoftFail;
2012   } else {
2013     // imod == '00' && M == '0' --> UNPREDICTABLE
2014     Inst.setOpcode(ARM::CPS1p);
2015     Inst.addOperand(MCOperand::createImm(mode));
2016     S = MCDisassembler::SoftFail;
2017   }
2018 
2019   return S;
2020 }
2021 
2022 static DecodeStatus DecodeT2CPSInstruction(MCInst &Inst, unsigned Insn,
2023                                  uint64_t Address, const void *Decoder) {
2024   unsigned imod = fieldFromInstruction(Insn, 9, 2);
2025   unsigned M = fieldFromInstruction(Insn, 8, 1);
2026   unsigned iflags = fieldFromInstruction(Insn, 5, 3);
2027   unsigned mode = fieldFromInstruction(Insn, 0, 5);
2028 
2029   DecodeStatus S = MCDisassembler::Success;
2030 
2031   // imod == '01' --> UNPREDICTABLE
2032   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
2033   // return failure here.  The '01' imod value is unprintable, so there's
2034   // nothing useful we could do even if we returned UNPREDICTABLE.
2035 
2036   if (imod == 1) return MCDisassembler::Fail;
2037 
2038   if (imod && M) {
2039     Inst.setOpcode(ARM::t2CPS3p);
2040     Inst.addOperand(MCOperand::createImm(imod));
2041     Inst.addOperand(MCOperand::createImm(iflags));
2042     Inst.addOperand(MCOperand::createImm(mode));
2043   } else if (imod && !M) {
2044     Inst.setOpcode(ARM::t2CPS2p);
2045     Inst.addOperand(MCOperand::createImm(imod));
2046     Inst.addOperand(MCOperand::createImm(iflags));
2047     if (mode) S = MCDisassembler::SoftFail;
2048   } else if (!imod && M) {
2049     Inst.setOpcode(ARM::t2CPS1p);
2050     Inst.addOperand(MCOperand::createImm(mode));
2051     if (iflags) S = MCDisassembler::SoftFail;
2052   } else {
2053     // imod == '00' && M == '0' --> this is a HINT instruction
2054     int imm = fieldFromInstruction(Insn, 0, 8);
2055     // HINT are defined only for immediate in [0..4]
2056     if(imm > 4) return MCDisassembler::Fail;
2057     Inst.setOpcode(ARM::t2HINT);
2058     Inst.addOperand(MCOperand::createImm(imm));
2059   }
2060 
2061   return S;
2062 }
2063 
2064 static DecodeStatus DecodeT2MOVTWInstruction(MCInst &Inst, unsigned Insn,
2065                                  uint64_t Address, const void *Decoder) {
2066   DecodeStatus S = MCDisassembler::Success;
2067 
2068   unsigned Rd = fieldFromInstruction(Insn, 8, 4);
2069   unsigned imm = 0;
2070 
2071   imm |= (fieldFromInstruction(Insn, 0, 8) << 0);
2072   imm |= (fieldFromInstruction(Insn, 12, 3) << 8);
2073   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
2074   imm |= (fieldFromInstruction(Insn, 26, 1) << 11);
2075 
2076   if (Inst.getOpcode() == ARM::t2MOVTi16)
2077     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2078       return MCDisassembler::Fail;
2079   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2080     return MCDisassembler::Fail;
2081 
2082   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
2083     Inst.addOperand(MCOperand::createImm(imm));
2084 
2085   return S;
2086 }
2087 
2088 static DecodeStatus DecodeArmMOVTWInstruction(MCInst &Inst, unsigned Insn,
2089                                  uint64_t Address, const void *Decoder) {
2090   DecodeStatus S = MCDisassembler::Success;
2091 
2092   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2093   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2094   unsigned imm = 0;
2095 
2096   imm |= (fieldFromInstruction(Insn, 0, 12) << 0);
2097   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
2098 
2099   if (Inst.getOpcode() == ARM::MOVTi16)
2100     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2101       return MCDisassembler::Fail;
2102 
2103   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2104     return MCDisassembler::Fail;
2105 
2106   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
2107     Inst.addOperand(MCOperand::createImm(imm));
2108 
2109   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2110     return MCDisassembler::Fail;
2111 
2112   return S;
2113 }
2114 
2115 static DecodeStatus DecodeSMLAInstruction(MCInst &Inst, unsigned Insn,
2116                                  uint64_t Address, const void *Decoder) {
2117   DecodeStatus S = MCDisassembler::Success;
2118 
2119   unsigned Rd = fieldFromInstruction(Insn, 16, 4);
2120   unsigned Rn = fieldFromInstruction(Insn, 0, 4);
2121   unsigned Rm = fieldFromInstruction(Insn, 8, 4);
2122   unsigned Ra = fieldFromInstruction(Insn, 12, 4);
2123   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2124 
2125   if (pred == 0xF)
2126     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
2127 
2128   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2129     return MCDisassembler::Fail;
2130   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2131     return MCDisassembler::Fail;
2132   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
2133     return MCDisassembler::Fail;
2134   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
2135     return MCDisassembler::Fail;
2136 
2137   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2138     return MCDisassembler::Fail;
2139 
2140   return S;
2141 }
2142 
2143 static DecodeStatus DecodeTSTInstruction(MCInst &Inst, unsigned Insn,
2144                                   uint64_t Address, const void *Decoder) {
2145   DecodeStatus S = MCDisassembler::Success;
2146 
2147   unsigned Pred = fieldFromInstruction(Insn, 28, 4);
2148   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2149   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2150 
2151   if (Pred == 0xF)
2152     return DecodeSETPANInstruction(Inst, Insn, Address, Decoder);
2153 
2154   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2155     return MCDisassembler::Fail;
2156   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2157     return MCDisassembler::Fail;
2158   if (!Check(S, DecodePredicateOperand(Inst, Pred, Address, Decoder)))
2159     return MCDisassembler::Fail;
2160 
2161   return S;
2162 }
2163 
2164 static DecodeStatus DecodeSETPANInstruction(MCInst &Inst, unsigned Insn,
2165                                   uint64_t Address, const void *Decoder) {
2166   DecodeStatus S = MCDisassembler::Success;
2167 
2168   unsigned Imm = fieldFromInstruction(Insn, 9, 1);
2169 
2170   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
2171   const FeatureBitset &FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
2172 
2173   if (!FeatureBits[ARM::HasV8_1aOps] ||
2174       !FeatureBits[ARM::HasV8Ops])
2175     return MCDisassembler::Fail;
2176 
2177   // Decoder can be called from DecodeTST, which does not check the full
2178   // encoding is valid.
2179   if (fieldFromInstruction(Insn, 20,12) != 0xf11 ||
2180       fieldFromInstruction(Insn, 4,4) != 0)
2181     return MCDisassembler::Fail;
2182   if (fieldFromInstruction(Insn, 10,10) != 0 ||
2183       fieldFromInstruction(Insn, 0,4) != 0)
2184     S = MCDisassembler::SoftFail;
2185 
2186   Inst.setOpcode(ARM::SETPAN);
2187   Inst.addOperand(MCOperand::createImm(Imm));
2188 
2189   return S;
2190 }
2191 
2192 static DecodeStatus DecodeAddrModeImm12Operand(MCInst &Inst, unsigned Val,
2193                            uint64_t Address, const void *Decoder) {
2194   DecodeStatus S = MCDisassembler::Success;
2195 
2196   unsigned add = fieldFromInstruction(Val, 12, 1);
2197   unsigned imm = fieldFromInstruction(Val, 0, 12);
2198   unsigned Rn = fieldFromInstruction(Val, 13, 4);
2199 
2200   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2201     return MCDisassembler::Fail;
2202 
2203   if (!add) imm *= -1;
2204   if (imm == 0 && !add) imm = INT32_MIN;
2205   Inst.addOperand(MCOperand::createImm(imm));
2206   if (Rn == 15)
2207     tryAddingPcLoadReferenceComment(Address, Address + imm + 8, Decoder);
2208 
2209   return S;
2210 }
2211 
2212 static DecodeStatus DecodeAddrMode5Operand(MCInst &Inst, unsigned Val,
2213                                    uint64_t Address, const void *Decoder) {
2214   DecodeStatus S = MCDisassembler::Success;
2215 
2216   unsigned Rn = fieldFromInstruction(Val, 9, 4);
2217   // U == 1 to add imm, 0 to subtract it.
2218   unsigned U = fieldFromInstruction(Val, 8, 1);
2219   unsigned imm = fieldFromInstruction(Val, 0, 8);
2220 
2221   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2222     return MCDisassembler::Fail;
2223 
2224   if (U)
2225     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
2226   else
2227     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
2228 
2229   return S;
2230 }
2231 
2232 static DecodeStatus DecodeAddrMode5FP16Operand(MCInst &Inst, unsigned Val,
2233                                    uint64_t Address, const void *Decoder) {
2234   DecodeStatus S = MCDisassembler::Success;
2235 
2236   unsigned Rn = fieldFromInstruction(Val, 9, 4);
2237   // U == 1 to add imm, 0 to subtract it.
2238   unsigned U = fieldFromInstruction(Val, 8, 1);
2239   unsigned imm = fieldFromInstruction(Val, 0, 8);
2240 
2241   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2242     return MCDisassembler::Fail;
2243 
2244   if (U)
2245     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5FP16Opc(ARM_AM::add, imm)));
2246   else
2247     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5FP16Opc(ARM_AM::sub, imm)));
2248 
2249   return S;
2250 }
2251 
2252 static DecodeStatus DecodeAddrMode7Operand(MCInst &Inst, unsigned Val,
2253                                    uint64_t Address, const void *Decoder) {
2254   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
2255 }
2256 
2257 static DecodeStatus
2258 DecodeT2BInstruction(MCInst &Inst, unsigned Insn,
2259                      uint64_t Address, const void *Decoder) {
2260   DecodeStatus Status = MCDisassembler::Success;
2261 
2262   // Note the J1 and J2 values are from the encoded instruction.  So here
2263   // change them to I1 and I2 values via as documented:
2264   // I1 = NOT(J1 EOR S);
2265   // I2 = NOT(J2 EOR S);
2266   // and build the imm32 with one trailing zero as documented:
2267   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
2268   unsigned S = fieldFromInstruction(Insn, 26, 1);
2269   unsigned J1 = fieldFromInstruction(Insn, 13, 1);
2270   unsigned J2 = fieldFromInstruction(Insn, 11, 1);
2271   unsigned I1 = !(J1 ^ S);
2272   unsigned I2 = !(J2 ^ S);
2273   unsigned imm10 = fieldFromInstruction(Insn, 16, 10);
2274   unsigned imm11 = fieldFromInstruction(Insn, 0, 11);
2275   unsigned tmp = (S << 23) | (I1 << 22) | (I2 << 21) | (imm10 << 11) | imm11;
2276   int imm32 = SignExtend32<25>(tmp << 1);
2277   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
2278                                 true, 4, Inst, Decoder))
2279     Inst.addOperand(MCOperand::createImm(imm32));
2280 
2281   return Status;
2282 }
2283 
2284 static DecodeStatus
2285 DecodeBranchImmInstruction(MCInst &Inst, unsigned Insn,
2286                            uint64_t Address, const void *Decoder) {
2287   DecodeStatus S = MCDisassembler::Success;
2288 
2289   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2290   unsigned imm = fieldFromInstruction(Insn, 0, 24) << 2;
2291 
2292   if (pred == 0xF) {
2293     Inst.setOpcode(ARM::BLXi);
2294     imm |= fieldFromInstruction(Insn, 24, 1) << 1;
2295     if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
2296                                   true, 4, Inst, Decoder))
2297     Inst.addOperand(MCOperand::createImm(SignExtend32<26>(imm)));
2298     return S;
2299   }
2300 
2301   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
2302                                 true, 4, Inst, Decoder))
2303     Inst.addOperand(MCOperand::createImm(SignExtend32<26>(imm)));
2304   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2305     return MCDisassembler::Fail;
2306 
2307   return S;
2308 }
2309 
2310 static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
2311                                    uint64_t Address, const void *Decoder) {
2312   DecodeStatus S = MCDisassembler::Success;
2313 
2314   unsigned Rm = fieldFromInstruction(Val, 0, 4);
2315   unsigned align = fieldFromInstruction(Val, 4, 2);
2316 
2317   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2318     return MCDisassembler::Fail;
2319   if (!align)
2320     Inst.addOperand(MCOperand::createImm(0));
2321   else
2322     Inst.addOperand(MCOperand::createImm(4 << align));
2323 
2324   return S;
2325 }
2326 
2327 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Insn,
2328                                    uint64_t Address, const void *Decoder) {
2329   DecodeStatus S = MCDisassembler::Success;
2330 
2331   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2332   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2333   unsigned wb = fieldFromInstruction(Insn, 16, 4);
2334   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2335   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
2336   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2337 
2338   // First output register
2339   switch (Inst.getOpcode()) {
2340   case ARM::VLD1q16: case ARM::VLD1q32: case ARM::VLD1q64: case ARM::VLD1q8:
2341   case ARM::VLD1q16wb_fixed: case ARM::VLD1q16wb_register:
2342   case ARM::VLD1q32wb_fixed: case ARM::VLD1q32wb_register:
2343   case ARM::VLD1q64wb_fixed: case ARM::VLD1q64wb_register:
2344   case ARM::VLD1q8wb_fixed: case ARM::VLD1q8wb_register:
2345   case ARM::VLD2d16: case ARM::VLD2d32: case ARM::VLD2d8:
2346   case ARM::VLD2d16wb_fixed: case ARM::VLD2d16wb_register:
2347   case ARM::VLD2d32wb_fixed: case ARM::VLD2d32wb_register:
2348   case ARM::VLD2d8wb_fixed: case ARM::VLD2d8wb_register:
2349     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2350       return MCDisassembler::Fail;
2351     break;
2352   case ARM::VLD2b16:
2353   case ARM::VLD2b32:
2354   case ARM::VLD2b8:
2355   case ARM::VLD2b16wb_fixed:
2356   case ARM::VLD2b16wb_register:
2357   case ARM::VLD2b32wb_fixed:
2358   case ARM::VLD2b32wb_register:
2359   case ARM::VLD2b8wb_fixed:
2360   case ARM::VLD2b8wb_register:
2361     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
2362       return MCDisassembler::Fail;
2363     break;
2364   default:
2365     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2366       return MCDisassembler::Fail;
2367   }
2368 
2369   // Second output register
2370   switch (Inst.getOpcode()) {
2371     case ARM::VLD3d8:
2372     case ARM::VLD3d16:
2373     case ARM::VLD3d32:
2374     case ARM::VLD3d8_UPD:
2375     case ARM::VLD3d16_UPD:
2376     case ARM::VLD3d32_UPD:
2377     case ARM::VLD4d8:
2378     case ARM::VLD4d16:
2379     case ARM::VLD4d32:
2380     case ARM::VLD4d8_UPD:
2381     case ARM::VLD4d16_UPD:
2382     case ARM::VLD4d32_UPD:
2383       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2384         return MCDisassembler::Fail;
2385       break;
2386     case ARM::VLD3q8:
2387     case ARM::VLD3q16:
2388     case ARM::VLD3q32:
2389     case ARM::VLD3q8_UPD:
2390     case ARM::VLD3q16_UPD:
2391     case ARM::VLD3q32_UPD:
2392     case ARM::VLD4q8:
2393     case ARM::VLD4q16:
2394     case ARM::VLD4q32:
2395     case ARM::VLD4q8_UPD:
2396     case ARM::VLD4q16_UPD:
2397     case ARM::VLD4q32_UPD:
2398       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2399         return MCDisassembler::Fail;
2400       break;
2401     default:
2402       break;
2403   }
2404 
2405   // Third output register
2406   switch(Inst.getOpcode()) {
2407     case ARM::VLD3d8:
2408     case ARM::VLD3d16:
2409     case ARM::VLD3d32:
2410     case ARM::VLD3d8_UPD:
2411     case ARM::VLD3d16_UPD:
2412     case ARM::VLD3d32_UPD:
2413     case ARM::VLD4d8:
2414     case ARM::VLD4d16:
2415     case ARM::VLD4d32:
2416     case ARM::VLD4d8_UPD:
2417     case ARM::VLD4d16_UPD:
2418     case ARM::VLD4d32_UPD:
2419       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2420         return MCDisassembler::Fail;
2421       break;
2422     case ARM::VLD3q8:
2423     case ARM::VLD3q16:
2424     case ARM::VLD3q32:
2425     case ARM::VLD3q8_UPD:
2426     case ARM::VLD3q16_UPD:
2427     case ARM::VLD3q32_UPD:
2428     case ARM::VLD4q8:
2429     case ARM::VLD4q16:
2430     case ARM::VLD4q32:
2431     case ARM::VLD4q8_UPD:
2432     case ARM::VLD4q16_UPD:
2433     case ARM::VLD4q32_UPD:
2434       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2435         return MCDisassembler::Fail;
2436       break;
2437     default:
2438       break;
2439   }
2440 
2441   // Fourth output register
2442   switch (Inst.getOpcode()) {
2443     case ARM::VLD4d8:
2444     case ARM::VLD4d16:
2445     case ARM::VLD4d32:
2446     case ARM::VLD4d8_UPD:
2447     case ARM::VLD4d16_UPD:
2448     case ARM::VLD4d32_UPD:
2449       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2450         return MCDisassembler::Fail;
2451       break;
2452     case ARM::VLD4q8:
2453     case ARM::VLD4q16:
2454     case ARM::VLD4q32:
2455     case ARM::VLD4q8_UPD:
2456     case ARM::VLD4q16_UPD:
2457     case ARM::VLD4q32_UPD:
2458       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2459         return MCDisassembler::Fail;
2460       break;
2461     default:
2462       break;
2463   }
2464 
2465   // Writeback operand
2466   switch (Inst.getOpcode()) {
2467     case ARM::VLD1d8wb_fixed:
2468     case ARM::VLD1d16wb_fixed:
2469     case ARM::VLD1d32wb_fixed:
2470     case ARM::VLD1d64wb_fixed:
2471     case ARM::VLD1d8wb_register:
2472     case ARM::VLD1d16wb_register:
2473     case ARM::VLD1d32wb_register:
2474     case ARM::VLD1d64wb_register:
2475     case ARM::VLD1q8wb_fixed:
2476     case ARM::VLD1q16wb_fixed:
2477     case ARM::VLD1q32wb_fixed:
2478     case ARM::VLD1q64wb_fixed:
2479     case ARM::VLD1q8wb_register:
2480     case ARM::VLD1q16wb_register:
2481     case ARM::VLD1q32wb_register:
2482     case ARM::VLD1q64wb_register:
2483     case ARM::VLD1d8Twb_fixed:
2484     case ARM::VLD1d8Twb_register:
2485     case ARM::VLD1d16Twb_fixed:
2486     case ARM::VLD1d16Twb_register:
2487     case ARM::VLD1d32Twb_fixed:
2488     case ARM::VLD1d32Twb_register:
2489     case ARM::VLD1d64Twb_fixed:
2490     case ARM::VLD1d64Twb_register:
2491     case ARM::VLD1d8Qwb_fixed:
2492     case ARM::VLD1d8Qwb_register:
2493     case ARM::VLD1d16Qwb_fixed:
2494     case ARM::VLD1d16Qwb_register:
2495     case ARM::VLD1d32Qwb_fixed:
2496     case ARM::VLD1d32Qwb_register:
2497     case ARM::VLD1d64Qwb_fixed:
2498     case ARM::VLD1d64Qwb_register:
2499     case ARM::VLD2d8wb_fixed:
2500     case ARM::VLD2d16wb_fixed:
2501     case ARM::VLD2d32wb_fixed:
2502     case ARM::VLD2q8wb_fixed:
2503     case ARM::VLD2q16wb_fixed:
2504     case ARM::VLD2q32wb_fixed:
2505     case ARM::VLD2d8wb_register:
2506     case ARM::VLD2d16wb_register:
2507     case ARM::VLD2d32wb_register:
2508     case ARM::VLD2q8wb_register:
2509     case ARM::VLD2q16wb_register:
2510     case ARM::VLD2q32wb_register:
2511     case ARM::VLD2b8wb_fixed:
2512     case ARM::VLD2b16wb_fixed:
2513     case ARM::VLD2b32wb_fixed:
2514     case ARM::VLD2b8wb_register:
2515     case ARM::VLD2b16wb_register:
2516     case ARM::VLD2b32wb_register:
2517       Inst.addOperand(MCOperand::createImm(0));
2518       break;
2519     case ARM::VLD3d8_UPD:
2520     case ARM::VLD3d16_UPD:
2521     case ARM::VLD3d32_UPD:
2522     case ARM::VLD3q8_UPD:
2523     case ARM::VLD3q16_UPD:
2524     case ARM::VLD3q32_UPD:
2525     case ARM::VLD4d8_UPD:
2526     case ARM::VLD4d16_UPD:
2527     case ARM::VLD4d32_UPD:
2528     case ARM::VLD4q8_UPD:
2529     case ARM::VLD4q16_UPD:
2530     case ARM::VLD4q32_UPD:
2531       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2532         return MCDisassembler::Fail;
2533       break;
2534     default:
2535       break;
2536   }
2537 
2538   // AddrMode6 Base (register+alignment)
2539   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2540     return MCDisassembler::Fail;
2541 
2542   // AddrMode6 Offset (register)
2543   switch (Inst.getOpcode()) {
2544   default:
2545     // The below have been updated to have explicit am6offset split
2546     // between fixed and register offset. For those instructions not
2547     // yet updated, we need to add an additional reg0 operand for the
2548     // fixed variant.
2549     //
2550     // The fixed offset encodes as Rm == 0xd, so we check for that.
2551     if (Rm == 0xd) {
2552       Inst.addOperand(MCOperand::createReg(0));
2553       break;
2554     }
2555     // Fall through to handle the register offset variant.
2556     LLVM_FALLTHROUGH;
2557   case ARM::VLD1d8wb_fixed:
2558   case ARM::VLD1d16wb_fixed:
2559   case ARM::VLD1d32wb_fixed:
2560   case ARM::VLD1d64wb_fixed:
2561   case ARM::VLD1d8Twb_fixed:
2562   case ARM::VLD1d16Twb_fixed:
2563   case ARM::VLD1d32Twb_fixed:
2564   case ARM::VLD1d64Twb_fixed:
2565   case ARM::VLD1d8Qwb_fixed:
2566   case ARM::VLD1d16Qwb_fixed:
2567   case ARM::VLD1d32Qwb_fixed:
2568   case ARM::VLD1d64Qwb_fixed:
2569   case ARM::VLD1d8wb_register:
2570   case ARM::VLD1d16wb_register:
2571   case ARM::VLD1d32wb_register:
2572   case ARM::VLD1d64wb_register:
2573   case ARM::VLD1q8wb_fixed:
2574   case ARM::VLD1q16wb_fixed:
2575   case ARM::VLD1q32wb_fixed:
2576   case ARM::VLD1q64wb_fixed:
2577   case ARM::VLD1q8wb_register:
2578   case ARM::VLD1q16wb_register:
2579   case ARM::VLD1q32wb_register:
2580   case ARM::VLD1q64wb_register:
2581     // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2582     // variant encodes Rm == 0xf. Anything else is a register offset post-
2583     // increment and we need to add the register operand to the instruction.
2584     if (Rm != 0xD && Rm != 0xF &&
2585         !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2586       return MCDisassembler::Fail;
2587     break;
2588   case ARM::VLD2d8wb_fixed:
2589   case ARM::VLD2d16wb_fixed:
2590   case ARM::VLD2d32wb_fixed:
2591   case ARM::VLD2b8wb_fixed:
2592   case ARM::VLD2b16wb_fixed:
2593   case ARM::VLD2b32wb_fixed:
2594   case ARM::VLD2q8wb_fixed:
2595   case ARM::VLD2q16wb_fixed:
2596   case ARM::VLD2q32wb_fixed:
2597     break;
2598   }
2599 
2600   return S;
2601 }
2602 
2603 static DecodeStatus DecodeVLDST1Instruction(MCInst &Inst, unsigned Insn,
2604                                    uint64_t Address, const void *Decoder) {
2605   unsigned type = fieldFromInstruction(Insn, 8, 4);
2606   unsigned align = fieldFromInstruction(Insn, 4, 2);
2607   if (type == 6 && (align & 2)) return MCDisassembler::Fail;
2608   if (type == 7 && (align & 2)) return MCDisassembler::Fail;
2609   if (type == 10 && align == 3) return MCDisassembler::Fail;
2610 
2611   unsigned load = fieldFromInstruction(Insn, 21, 1);
2612   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2613               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2614 }
2615 
2616 static DecodeStatus DecodeVLDST2Instruction(MCInst &Inst, unsigned Insn,
2617                                    uint64_t Address, const void *Decoder) {
2618   unsigned size = fieldFromInstruction(Insn, 6, 2);
2619   if (size == 3) return MCDisassembler::Fail;
2620 
2621   unsigned type = fieldFromInstruction(Insn, 8, 4);
2622   unsigned align = fieldFromInstruction(Insn, 4, 2);
2623   if (type == 8 && align == 3) return MCDisassembler::Fail;
2624   if (type == 9 && align == 3) return MCDisassembler::Fail;
2625 
2626   unsigned load = fieldFromInstruction(Insn, 21, 1);
2627   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2628               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2629 }
2630 
2631 static DecodeStatus DecodeVLDST3Instruction(MCInst &Inst, unsigned Insn,
2632                                    uint64_t Address, const void *Decoder) {
2633   unsigned size = fieldFromInstruction(Insn, 6, 2);
2634   if (size == 3) return MCDisassembler::Fail;
2635 
2636   unsigned align = fieldFromInstruction(Insn, 4, 2);
2637   if (align & 2) return MCDisassembler::Fail;
2638 
2639   unsigned load = fieldFromInstruction(Insn, 21, 1);
2640   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2641               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2642 }
2643 
2644 static DecodeStatus DecodeVLDST4Instruction(MCInst &Inst, unsigned Insn,
2645                                    uint64_t Address, const void *Decoder) {
2646   unsigned size = fieldFromInstruction(Insn, 6, 2);
2647   if (size == 3) return MCDisassembler::Fail;
2648 
2649   unsigned load = fieldFromInstruction(Insn, 21, 1);
2650   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2651               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2652 }
2653 
2654 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Insn,
2655                                  uint64_t Address, const void *Decoder) {
2656   DecodeStatus S = MCDisassembler::Success;
2657 
2658   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2659   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2660   unsigned wb = fieldFromInstruction(Insn, 16, 4);
2661   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2662   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
2663   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2664 
2665   // Writeback Operand
2666   switch (Inst.getOpcode()) {
2667     case ARM::VST1d8wb_fixed:
2668     case ARM::VST1d16wb_fixed:
2669     case ARM::VST1d32wb_fixed:
2670     case ARM::VST1d64wb_fixed:
2671     case ARM::VST1d8wb_register:
2672     case ARM::VST1d16wb_register:
2673     case ARM::VST1d32wb_register:
2674     case ARM::VST1d64wb_register:
2675     case ARM::VST1q8wb_fixed:
2676     case ARM::VST1q16wb_fixed:
2677     case ARM::VST1q32wb_fixed:
2678     case ARM::VST1q64wb_fixed:
2679     case ARM::VST1q8wb_register:
2680     case ARM::VST1q16wb_register:
2681     case ARM::VST1q32wb_register:
2682     case ARM::VST1q64wb_register:
2683     case ARM::VST1d8Twb_fixed:
2684     case ARM::VST1d16Twb_fixed:
2685     case ARM::VST1d32Twb_fixed:
2686     case ARM::VST1d64Twb_fixed:
2687     case ARM::VST1d8Twb_register:
2688     case ARM::VST1d16Twb_register:
2689     case ARM::VST1d32Twb_register:
2690     case ARM::VST1d64Twb_register:
2691     case ARM::VST1d8Qwb_fixed:
2692     case ARM::VST1d16Qwb_fixed:
2693     case ARM::VST1d32Qwb_fixed:
2694     case ARM::VST1d64Qwb_fixed:
2695     case ARM::VST1d8Qwb_register:
2696     case ARM::VST1d16Qwb_register:
2697     case ARM::VST1d32Qwb_register:
2698     case ARM::VST1d64Qwb_register:
2699     case ARM::VST2d8wb_fixed:
2700     case ARM::VST2d16wb_fixed:
2701     case ARM::VST2d32wb_fixed:
2702     case ARM::VST2d8wb_register:
2703     case ARM::VST2d16wb_register:
2704     case ARM::VST2d32wb_register:
2705     case ARM::VST2q8wb_fixed:
2706     case ARM::VST2q16wb_fixed:
2707     case ARM::VST2q32wb_fixed:
2708     case ARM::VST2q8wb_register:
2709     case ARM::VST2q16wb_register:
2710     case ARM::VST2q32wb_register:
2711     case ARM::VST2b8wb_fixed:
2712     case ARM::VST2b16wb_fixed:
2713     case ARM::VST2b32wb_fixed:
2714     case ARM::VST2b8wb_register:
2715     case ARM::VST2b16wb_register:
2716     case ARM::VST2b32wb_register:
2717       if (Rm == 0xF)
2718         return MCDisassembler::Fail;
2719       Inst.addOperand(MCOperand::createImm(0));
2720       break;
2721     case ARM::VST3d8_UPD:
2722     case ARM::VST3d16_UPD:
2723     case ARM::VST3d32_UPD:
2724     case ARM::VST3q8_UPD:
2725     case ARM::VST3q16_UPD:
2726     case ARM::VST3q32_UPD:
2727     case ARM::VST4d8_UPD:
2728     case ARM::VST4d16_UPD:
2729     case ARM::VST4d32_UPD:
2730     case ARM::VST4q8_UPD:
2731     case ARM::VST4q16_UPD:
2732     case ARM::VST4q32_UPD:
2733       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2734         return MCDisassembler::Fail;
2735       break;
2736     default:
2737       break;
2738   }
2739 
2740   // AddrMode6 Base (register+alignment)
2741   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2742     return MCDisassembler::Fail;
2743 
2744   // AddrMode6 Offset (register)
2745   switch (Inst.getOpcode()) {
2746     default:
2747       if (Rm == 0xD)
2748         Inst.addOperand(MCOperand::createReg(0));
2749       else if (Rm != 0xF) {
2750         if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2751           return MCDisassembler::Fail;
2752       }
2753       break;
2754     case ARM::VST1d8wb_fixed:
2755     case ARM::VST1d16wb_fixed:
2756     case ARM::VST1d32wb_fixed:
2757     case ARM::VST1d64wb_fixed:
2758     case ARM::VST1q8wb_fixed:
2759     case ARM::VST1q16wb_fixed:
2760     case ARM::VST1q32wb_fixed:
2761     case ARM::VST1q64wb_fixed:
2762     case ARM::VST1d8Twb_fixed:
2763     case ARM::VST1d16Twb_fixed:
2764     case ARM::VST1d32Twb_fixed:
2765     case ARM::VST1d64Twb_fixed:
2766     case ARM::VST1d8Qwb_fixed:
2767     case ARM::VST1d16Qwb_fixed:
2768     case ARM::VST1d32Qwb_fixed:
2769     case ARM::VST1d64Qwb_fixed:
2770     case ARM::VST2d8wb_fixed:
2771     case ARM::VST2d16wb_fixed:
2772     case ARM::VST2d32wb_fixed:
2773     case ARM::VST2q8wb_fixed:
2774     case ARM::VST2q16wb_fixed:
2775     case ARM::VST2q32wb_fixed:
2776     case ARM::VST2b8wb_fixed:
2777     case ARM::VST2b16wb_fixed:
2778     case ARM::VST2b32wb_fixed:
2779       break;
2780   }
2781 
2782   // First input register
2783   switch (Inst.getOpcode()) {
2784   case ARM::VST1q16:
2785   case ARM::VST1q32:
2786   case ARM::VST1q64:
2787   case ARM::VST1q8:
2788   case ARM::VST1q16wb_fixed:
2789   case ARM::VST1q16wb_register:
2790   case ARM::VST1q32wb_fixed:
2791   case ARM::VST1q32wb_register:
2792   case ARM::VST1q64wb_fixed:
2793   case ARM::VST1q64wb_register:
2794   case ARM::VST1q8wb_fixed:
2795   case ARM::VST1q8wb_register:
2796   case ARM::VST2d16:
2797   case ARM::VST2d32:
2798   case ARM::VST2d8:
2799   case ARM::VST2d16wb_fixed:
2800   case ARM::VST2d16wb_register:
2801   case ARM::VST2d32wb_fixed:
2802   case ARM::VST2d32wb_register:
2803   case ARM::VST2d8wb_fixed:
2804   case ARM::VST2d8wb_register:
2805     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2806       return MCDisassembler::Fail;
2807     break;
2808   case ARM::VST2b16:
2809   case ARM::VST2b32:
2810   case ARM::VST2b8:
2811   case ARM::VST2b16wb_fixed:
2812   case ARM::VST2b16wb_register:
2813   case ARM::VST2b32wb_fixed:
2814   case ARM::VST2b32wb_register:
2815   case ARM::VST2b8wb_fixed:
2816   case ARM::VST2b8wb_register:
2817     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
2818       return MCDisassembler::Fail;
2819     break;
2820   default:
2821     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2822       return MCDisassembler::Fail;
2823   }
2824 
2825   // Second input register
2826   switch (Inst.getOpcode()) {
2827     case ARM::VST3d8:
2828     case ARM::VST3d16:
2829     case ARM::VST3d32:
2830     case ARM::VST3d8_UPD:
2831     case ARM::VST3d16_UPD:
2832     case ARM::VST3d32_UPD:
2833     case ARM::VST4d8:
2834     case ARM::VST4d16:
2835     case ARM::VST4d32:
2836     case ARM::VST4d8_UPD:
2837     case ARM::VST4d16_UPD:
2838     case ARM::VST4d32_UPD:
2839       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2840         return MCDisassembler::Fail;
2841       break;
2842     case ARM::VST3q8:
2843     case ARM::VST3q16:
2844     case ARM::VST3q32:
2845     case ARM::VST3q8_UPD:
2846     case ARM::VST3q16_UPD:
2847     case ARM::VST3q32_UPD:
2848     case ARM::VST4q8:
2849     case ARM::VST4q16:
2850     case ARM::VST4q32:
2851     case ARM::VST4q8_UPD:
2852     case ARM::VST4q16_UPD:
2853     case ARM::VST4q32_UPD:
2854       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2855         return MCDisassembler::Fail;
2856       break;
2857     default:
2858       break;
2859   }
2860 
2861   // Third input register
2862   switch (Inst.getOpcode()) {
2863     case ARM::VST3d8:
2864     case ARM::VST3d16:
2865     case ARM::VST3d32:
2866     case ARM::VST3d8_UPD:
2867     case ARM::VST3d16_UPD:
2868     case ARM::VST3d32_UPD:
2869     case ARM::VST4d8:
2870     case ARM::VST4d16:
2871     case ARM::VST4d32:
2872     case ARM::VST4d8_UPD:
2873     case ARM::VST4d16_UPD:
2874     case ARM::VST4d32_UPD:
2875       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2876         return MCDisassembler::Fail;
2877       break;
2878     case ARM::VST3q8:
2879     case ARM::VST3q16:
2880     case ARM::VST3q32:
2881     case ARM::VST3q8_UPD:
2882     case ARM::VST3q16_UPD:
2883     case ARM::VST3q32_UPD:
2884     case ARM::VST4q8:
2885     case ARM::VST4q16:
2886     case ARM::VST4q32:
2887     case ARM::VST4q8_UPD:
2888     case ARM::VST4q16_UPD:
2889     case ARM::VST4q32_UPD:
2890       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2891         return MCDisassembler::Fail;
2892       break;
2893     default:
2894       break;
2895   }
2896 
2897   // Fourth input register
2898   switch (Inst.getOpcode()) {
2899     case ARM::VST4d8:
2900     case ARM::VST4d16:
2901     case ARM::VST4d32:
2902     case ARM::VST4d8_UPD:
2903     case ARM::VST4d16_UPD:
2904     case ARM::VST4d32_UPD:
2905       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2906         return MCDisassembler::Fail;
2907       break;
2908     case ARM::VST4q8:
2909     case ARM::VST4q16:
2910     case ARM::VST4q32:
2911     case ARM::VST4q8_UPD:
2912     case ARM::VST4q16_UPD:
2913     case ARM::VST4q32_UPD:
2914       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2915         return MCDisassembler::Fail;
2916       break;
2917     default:
2918       break;
2919   }
2920 
2921   return S;
2922 }
2923 
2924 static DecodeStatus DecodeVLD1DupInstruction(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 Rn = fieldFromInstruction(Insn, 16, 4);
2931   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2932   unsigned align = fieldFromInstruction(Insn, 4, 1);
2933   unsigned size = fieldFromInstruction(Insn, 6, 2);
2934 
2935   if (size == 0 && align == 1)
2936     return MCDisassembler::Fail;
2937   align *= (1 << size);
2938 
2939   switch (Inst.getOpcode()) {
2940   case ARM::VLD1DUPq16: case ARM::VLD1DUPq32: case ARM::VLD1DUPq8:
2941   case ARM::VLD1DUPq16wb_fixed: case ARM::VLD1DUPq16wb_register:
2942   case ARM::VLD1DUPq32wb_fixed: case ARM::VLD1DUPq32wb_register:
2943   case ARM::VLD1DUPq8wb_fixed: case ARM::VLD1DUPq8wb_register:
2944     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2945       return MCDisassembler::Fail;
2946     break;
2947   default:
2948     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2949       return MCDisassembler::Fail;
2950     break;
2951   }
2952   if (Rm != 0xF) {
2953     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2954       return MCDisassembler::Fail;
2955   }
2956 
2957   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2958     return MCDisassembler::Fail;
2959   Inst.addOperand(MCOperand::createImm(align));
2960 
2961   // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2962   // variant encodes Rm == 0xf. Anything else is a register offset post-
2963   // increment and we need to add the register operand to the instruction.
2964   if (Rm != 0xD && Rm != 0xF &&
2965       !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2966     return MCDisassembler::Fail;
2967 
2968   return S;
2969 }
2970 
2971 static DecodeStatus DecodeVLD2DupInstruction(MCInst &Inst, unsigned Insn,
2972                                     uint64_t Address, const void *Decoder) {
2973   DecodeStatus S = MCDisassembler::Success;
2974 
2975   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2976   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2977   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2978   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2979   unsigned align = fieldFromInstruction(Insn, 4, 1);
2980   unsigned size = 1 << fieldFromInstruction(Insn, 6, 2);
2981   align *= 2*size;
2982 
2983   switch (Inst.getOpcode()) {
2984   case ARM::VLD2DUPd16: case ARM::VLD2DUPd32: case ARM::VLD2DUPd8:
2985   case ARM::VLD2DUPd16wb_fixed: case ARM::VLD2DUPd16wb_register:
2986   case ARM::VLD2DUPd32wb_fixed: case ARM::VLD2DUPd32wb_register:
2987   case ARM::VLD2DUPd8wb_fixed: case ARM::VLD2DUPd8wb_register:
2988     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2989       return MCDisassembler::Fail;
2990     break;
2991   case ARM::VLD2DUPd16x2: case ARM::VLD2DUPd32x2: case ARM::VLD2DUPd8x2:
2992   case ARM::VLD2DUPd16x2wb_fixed: case ARM::VLD2DUPd16x2wb_register:
2993   case ARM::VLD2DUPd32x2wb_fixed: case ARM::VLD2DUPd32x2wb_register:
2994   case ARM::VLD2DUPd8x2wb_fixed: case ARM::VLD2DUPd8x2wb_register:
2995     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
2996       return MCDisassembler::Fail;
2997     break;
2998   default:
2999     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3000       return MCDisassembler::Fail;
3001     break;
3002   }
3003 
3004   if (Rm != 0xF)
3005     Inst.addOperand(MCOperand::createImm(0));
3006 
3007   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3008     return MCDisassembler::Fail;
3009   Inst.addOperand(MCOperand::createImm(align));
3010 
3011   if (Rm != 0xD && Rm != 0xF) {
3012     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3013       return MCDisassembler::Fail;
3014   }
3015 
3016   return S;
3017 }
3018 
3019 static DecodeStatus DecodeVLD3DupInstruction(MCInst &Inst, unsigned Insn,
3020                                     uint64_t Address, const void *Decoder) {
3021   DecodeStatus S = MCDisassembler::Success;
3022 
3023   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3024   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3025   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3026   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3027   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
3028 
3029   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3030     return MCDisassembler::Fail;
3031   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
3032     return MCDisassembler::Fail;
3033   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
3034     return MCDisassembler::Fail;
3035   if (Rm != 0xF) {
3036     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3037       return MCDisassembler::Fail;
3038   }
3039 
3040   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3041     return MCDisassembler::Fail;
3042   Inst.addOperand(MCOperand::createImm(0));
3043 
3044   if (Rm == 0xD)
3045     Inst.addOperand(MCOperand::createReg(0));
3046   else if (Rm != 0xF) {
3047     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3048       return MCDisassembler::Fail;
3049   }
3050 
3051   return S;
3052 }
3053 
3054 static DecodeStatus DecodeVLD4DupInstruction(MCInst &Inst, unsigned Insn,
3055                                     uint64_t Address, const void *Decoder) {
3056   DecodeStatus S = MCDisassembler::Success;
3057 
3058   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3059   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3060   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3061   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3062   unsigned size = fieldFromInstruction(Insn, 6, 2);
3063   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
3064   unsigned align = fieldFromInstruction(Insn, 4, 1);
3065 
3066   if (size == 0x3) {
3067     if (align == 0)
3068       return MCDisassembler::Fail;
3069     align = 16;
3070   } else {
3071     if (size == 2) {
3072       align *= 8;
3073     } else {
3074       size = 1 << size;
3075       align *= 4*size;
3076     }
3077   }
3078 
3079   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3080     return MCDisassembler::Fail;
3081   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
3082     return MCDisassembler::Fail;
3083   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
3084     return MCDisassembler::Fail;
3085   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
3086     return MCDisassembler::Fail;
3087   if (Rm != 0xF) {
3088     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3089       return MCDisassembler::Fail;
3090   }
3091 
3092   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3093     return MCDisassembler::Fail;
3094   Inst.addOperand(MCOperand::createImm(align));
3095 
3096   if (Rm == 0xD)
3097     Inst.addOperand(MCOperand::createReg(0));
3098   else if (Rm != 0xF) {
3099     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3100       return MCDisassembler::Fail;
3101   }
3102 
3103   return S;
3104 }
3105 
3106 static DecodeStatus
3107 DecodeNEONModImmInstruction(MCInst &Inst, unsigned Insn,
3108                             uint64_t Address, const void *Decoder) {
3109   DecodeStatus S = MCDisassembler::Success;
3110 
3111   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3112   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3113   unsigned imm = fieldFromInstruction(Insn, 0, 4);
3114   imm |= fieldFromInstruction(Insn, 16, 3) << 4;
3115   imm |= fieldFromInstruction(Insn, 24, 1) << 7;
3116   imm |= fieldFromInstruction(Insn, 8, 4) << 8;
3117   imm |= fieldFromInstruction(Insn, 5, 1) << 12;
3118   unsigned Q = fieldFromInstruction(Insn, 6, 1);
3119 
3120   if (Q) {
3121     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3122     return MCDisassembler::Fail;
3123   } else {
3124     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3125     return MCDisassembler::Fail;
3126   }
3127 
3128   Inst.addOperand(MCOperand::createImm(imm));
3129 
3130   switch (Inst.getOpcode()) {
3131     case ARM::VORRiv4i16:
3132     case ARM::VORRiv2i32:
3133     case ARM::VBICiv4i16:
3134     case ARM::VBICiv2i32:
3135       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3136         return MCDisassembler::Fail;
3137       break;
3138     case ARM::VORRiv8i16:
3139     case ARM::VORRiv4i32:
3140     case ARM::VBICiv8i16:
3141     case ARM::VBICiv4i32:
3142       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3143         return MCDisassembler::Fail;
3144       break;
3145     default:
3146       break;
3147   }
3148 
3149   return S;
3150 }
3151 
3152 static DecodeStatus DecodeVSHLMaxInstruction(MCInst &Inst, unsigned Insn,
3153                                         uint64_t Address, const void *Decoder) {
3154   DecodeStatus S = MCDisassembler::Success;
3155 
3156   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3157   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3158   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3159   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
3160   unsigned size = fieldFromInstruction(Insn, 18, 2);
3161 
3162   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3163     return MCDisassembler::Fail;
3164   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
3165     return MCDisassembler::Fail;
3166   Inst.addOperand(MCOperand::createImm(8 << size));
3167 
3168   return S;
3169 }
3170 
3171 static DecodeStatus DecodeShiftRight8Imm(MCInst &Inst, unsigned Val,
3172                                uint64_t Address, const void *Decoder) {
3173   Inst.addOperand(MCOperand::createImm(8 - Val));
3174   return MCDisassembler::Success;
3175 }
3176 
3177 static DecodeStatus DecodeShiftRight16Imm(MCInst &Inst, unsigned Val,
3178                                uint64_t Address, const void *Decoder) {
3179   Inst.addOperand(MCOperand::createImm(16 - Val));
3180   return MCDisassembler::Success;
3181 }
3182 
3183 static DecodeStatus DecodeShiftRight32Imm(MCInst &Inst, unsigned Val,
3184                                uint64_t Address, const void *Decoder) {
3185   Inst.addOperand(MCOperand::createImm(32 - Val));
3186   return MCDisassembler::Success;
3187 }
3188 
3189 static DecodeStatus DecodeShiftRight64Imm(MCInst &Inst, unsigned Val,
3190                                uint64_t Address, const void *Decoder) {
3191   Inst.addOperand(MCOperand::createImm(64 - Val));
3192   return MCDisassembler::Success;
3193 }
3194 
3195 static DecodeStatus DecodeTBLInstruction(MCInst &Inst, unsigned Insn,
3196                                uint64_t Address, const void *Decoder) {
3197   DecodeStatus S = MCDisassembler::Success;
3198 
3199   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3200   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3201   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3202   Rn |= fieldFromInstruction(Insn, 7, 1) << 4;
3203   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3204   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
3205   unsigned op = fieldFromInstruction(Insn, 6, 1);
3206 
3207   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3208     return MCDisassembler::Fail;
3209   if (op) {
3210     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3211     return MCDisassembler::Fail; // Writeback
3212   }
3213 
3214   switch (Inst.getOpcode()) {
3215   case ARM::VTBL2:
3216   case ARM::VTBX2:
3217     if (!Check(S, DecodeDPairRegisterClass(Inst, Rn, Address, Decoder)))
3218       return MCDisassembler::Fail;
3219     break;
3220   default:
3221     if (!Check(S, DecodeDPRRegisterClass(Inst, Rn, Address, Decoder)))
3222       return MCDisassembler::Fail;
3223   }
3224 
3225   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
3226     return MCDisassembler::Fail;
3227 
3228   return S;
3229 }
3230 
3231 static DecodeStatus DecodeThumbAddSpecialReg(MCInst &Inst, uint16_t Insn,
3232                                      uint64_t Address, const void *Decoder) {
3233   DecodeStatus S = MCDisassembler::Success;
3234 
3235   unsigned dst = fieldFromInstruction(Insn, 8, 3);
3236   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3237 
3238   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
3239     return MCDisassembler::Fail;
3240 
3241   switch(Inst.getOpcode()) {
3242     default:
3243       return MCDisassembler::Fail;
3244     case ARM::tADR:
3245       break; // tADR does not explicitly represent the PC as an operand.
3246     case ARM::tADDrSPi:
3247       Inst.addOperand(MCOperand::createReg(ARM::SP));
3248       break;
3249   }
3250 
3251   Inst.addOperand(MCOperand::createImm(imm));
3252   return S;
3253 }
3254 
3255 static DecodeStatus DecodeThumbBROperand(MCInst &Inst, unsigned Val,
3256                                  uint64_t Address, const void *Decoder) {
3257   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<12>(Val<<1) + 4,
3258                                 true, 2, Inst, Decoder))
3259     Inst.addOperand(MCOperand::createImm(SignExtend32<12>(Val << 1)));
3260   return MCDisassembler::Success;
3261 }
3262 
3263 static DecodeStatus DecodeT2BROperand(MCInst &Inst, unsigned Val,
3264                                  uint64_t Address, const void *Decoder) {
3265   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<21>(Val) + 4,
3266                                 true, 4, Inst, Decoder))
3267     Inst.addOperand(MCOperand::createImm(SignExtend32<21>(Val)));
3268   return MCDisassembler::Success;
3269 }
3270 
3271 static DecodeStatus DecodeThumbCmpBROperand(MCInst &Inst, unsigned Val,
3272                                  uint64_t Address, const void *Decoder) {
3273   if (!tryAddingSymbolicOperand(Address, Address + (Val<<1) + 4,
3274                                 true, 2, Inst, Decoder))
3275     Inst.addOperand(MCOperand::createImm(Val << 1));
3276   return MCDisassembler::Success;
3277 }
3278 
3279 static DecodeStatus DecodeThumbAddrModeRR(MCInst &Inst, unsigned Val,
3280                                  uint64_t Address, const void *Decoder) {
3281   DecodeStatus S = MCDisassembler::Success;
3282 
3283   unsigned Rn = fieldFromInstruction(Val, 0, 3);
3284   unsigned Rm = fieldFromInstruction(Val, 3, 3);
3285 
3286   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
3287     return MCDisassembler::Fail;
3288   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
3289     return MCDisassembler::Fail;
3290 
3291   return S;
3292 }
3293 
3294 static DecodeStatus DecodeThumbAddrModeIS(MCInst &Inst, unsigned Val,
3295                                   uint64_t Address, const void *Decoder) {
3296   DecodeStatus S = MCDisassembler::Success;
3297 
3298   unsigned Rn = fieldFromInstruction(Val, 0, 3);
3299   unsigned imm = fieldFromInstruction(Val, 3, 5);
3300 
3301   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
3302     return MCDisassembler::Fail;
3303   Inst.addOperand(MCOperand::createImm(imm));
3304 
3305   return S;
3306 }
3307 
3308 static DecodeStatus DecodeThumbAddrModePC(MCInst &Inst, unsigned Val,
3309                                   uint64_t Address, const void *Decoder) {
3310   unsigned imm = Val << 2;
3311 
3312   Inst.addOperand(MCOperand::createImm(imm));
3313   tryAddingPcLoadReferenceComment(Address, (Address & ~2u) + imm + 4, Decoder);
3314 
3315   return MCDisassembler::Success;
3316 }
3317 
3318 static DecodeStatus DecodeThumbAddrModeSP(MCInst &Inst, unsigned Val,
3319                                   uint64_t Address, const void *Decoder) {
3320   Inst.addOperand(MCOperand::createReg(ARM::SP));
3321   Inst.addOperand(MCOperand::createImm(Val));
3322 
3323   return MCDisassembler::Success;
3324 }
3325 
3326 static DecodeStatus DecodeT2AddrModeSOReg(MCInst &Inst, unsigned Val,
3327                                   uint64_t Address, const void *Decoder) {
3328   DecodeStatus S = MCDisassembler::Success;
3329 
3330   unsigned Rn = fieldFromInstruction(Val, 6, 4);
3331   unsigned Rm = fieldFromInstruction(Val, 2, 4);
3332   unsigned imm = fieldFromInstruction(Val, 0, 2);
3333 
3334   // Thumb stores cannot use PC as dest register.
3335   switch (Inst.getOpcode()) {
3336   case ARM::t2STRHs:
3337   case ARM::t2STRBs:
3338   case ARM::t2STRs:
3339     if (Rn == 15)
3340       return MCDisassembler::Fail;
3341     break;
3342   default:
3343     break;
3344   }
3345 
3346   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3347     return MCDisassembler::Fail;
3348   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
3349     return MCDisassembler::Fail;
3350   Inst.addOperand(MCOperand::createImm(imm));
3351 
3352   return S;
3353 }
3354 
3355 static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Insn,
3356                               uint64_t Address, const void *Decoder) {
3357   DecodeStatus S = MCDisassembler::Success;
3358 
3359   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3360   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3361 
3362   const FeatureBitset &featureBits =
3363     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3364 
3365   bool hasMP = featureBits[ARM::FeatureMP];
3366   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3367 
3368   if (Rn == 15) {
3369     switch (Inst.getOpcode()) {
3370     case ARM::t2LDRBs:
3371       Inst.setOpcode(ARM::t2LDRBpci);
3372       break;
3373     case ARM::t2LDRHs:
3374       Inst.setOpcode(ARM::t2LDRHpci);
3375       break;
3376     case ARM::t2LDRSHs:
3377       Inst.setOpcode(ARM::t2LDRSHpci);
3378       break;
3379     case ARM::t2LDRSBs:
3380       Inst.setOpcode(ARM::t2LDRSBpci);
3381       break;
3382     case ARM::t2LDRs:
3383       Inst.setOpcode(ARM::t2LDRpci);
3384       break;
3385     case ARM::t2PLDs:
3386       Inst.setOpcode(ARM::t2PLDpci);
3387       break;
3388     case ARM::t2PLIs:
3389       Inst.setOpcode(ARM::t2PLIpci);
3390       break;
3391     default:
3392       return MCDisassembler::Fail;
3393     }
3394 
3395     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3396   }
3397 
3398   if (Rt == 15) {
3399     switch (Inst.getOpcode()) {
3400     case ARM::t2LDRSHs:
3401       return MCDisassembler::Fail;
3402     case ARM::t2LDRHs:
3403       Inst.setOpcode(ARM::t2PLDWs);
3404       break;
3405     case ARM::t2LDRSBs:
3406       Inst.setOpcode(ARM::t2PLIs);
3407       break;
3408     default:
3409       break;
3410     }
3411   }
3412 
3413   switch (Inst.getOpcode()) {
3414     case ARM::t2PLDs:
3415       break;
3416     case ARM::t2PLIs:
3417       if (!hasV7Ops)
3418         return MCDisassembler::Fail;
3419       break;
3420     case ARM::t2PLDWs:
3421       if (!hasV7Ops || !hasMP)
3422         return MCDisassembler::Fail;
3423       break;
3424     default:
3425       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3426         return MCDisassembler::Fail;
3427   }
3428 
3429   unsigned addrmode = fieldFromInstruction(Insn, 4, 2);
3430   addrmode |= fieldFromInstruction(Insn, 0, 4) << 2;
3431   addrmode |= fieldFromInstruction(Insn, 16, 4) << 6;
3432   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
3433     return MCDisassembler::Fail;
3434 
3435   return S;
3436 }
3437 
3438 static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
3439                                 uint64_t Address, const void* Decoder) {
3440   DecodeStatus S = MCDisassembler::Success;
3441 
3442   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3443   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3444   unsigned U = fieldFromInstruction(Insn, 9, 1);
3445   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3446   imm |= (U << 8);
3447   imm |= (Rn << 9);
3448   unsigned add = fieldFromInstruction(Insn, 9, 1);
3449 
3450   const FeatureBitset &featureBits =
3451     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3452 
3453   bool hasMP = featureBits[ARM::FeatureMP];
3454   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3455 
3456   if (Rn == 15) {
3457     switch (Inst.getOpcode()) {
3458     case ARM::t2LDRi8:
3459       Inst.setOpcode(ARM::t2LDRpci);
3460       break;
3461     case ARM::t2LDRBi8:
3462       Inst.setOpcode(ARM::t2LDRBpci);
3463       break;
3464     case ARM::t2LDRSBi8:
3465       Inst.setOpcode(ARM::t2LDRSBpci);
3466       break;
3467     case ARM::t2LDRHi8:
3468       Inst.setOpcode(ARM::t2LDRHpci);
3469       break;
3470     case ARM::t2LDRSHi8:
3471       Inst.setOpcode(ARM::t2LDRSHpci);
3472       break;
3473     case ARM::t2PLDi8:
3474       Inst.setOpcode(ARM::t2PLDpci);
3475       break;
3476     case ARM::t2PLIi8:
3477       Inst.setOpcode(ARM::t2PLIpci);
3478       break;
3479     default:
3480       return MCDisassembler::Fail;
3481     }
3482     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3483   }
3484 
3485   if (Rt == 15) {
3486     switch (Inst.getOpcode()) {
3487     case ARM::t2LDRSHi8:
3488       return MCDisassembler::Fail;
3489     case ARM::t2LDRHi8:
3490       if (!add)
3491         Inst.setOpcode(ARM::t2PLDWi8);
3492       break;
3493     case ARM::t2LDRSBi8:
3494       Inst.setOpcode(ARM::t2PLIi8);
3495       break;
3496     default:
3497       break;
3498     }
3499   }
3500 
3501   switch (Inst.getOpcode()) {
3502   case ARM::t2PLDi8:
3503     break;
3504   case ARM::t2PLIi8:
3505     if (!hasV7Ops)
3506       return MCDisassembler::Fail;
3507     break;
3508   case ARM::t2PLDWi8:
3509       if (!hasV7Ops || !hasMP)
3510         return MCDisassembler::Fail;
3511       break;
3512   default:
3513     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3514       return MCDisassembler::Fail;
3515   }
3516 
3517   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
3518     return MCDisassembler::Fail;
3519   return S;
3520 }
3521 
3522 static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
3523                                 uint64_t Address, const void* Decoder) {
3524   DecodeStatus S = MCDisassembler::Success;
3525 
3526   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3527   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3528   unsigned imm = fieldFromInstruction(Insn, 0, 12);
3529   imm |= (Rn << 13);
3530 
3531   const FeatureBitset &featureBits =
3532     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3533 
3534   bool hasMP = featureBits[ARM::FeatureMP];
3535   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3536 
3537   if (Rn == 15) {
3538     switch (Inst.getOpcode()) {
3539     case ARM::t2LDRi12:
3540       Inst.setOpcode(ARM::t2LDRpci);
3541       break;
3542     case ARM::t2LDRHi12:
3543       Inst.setOpcode(ARM::t2LDRHpci);
3544       break;
3545     case ARM::t2LDRSHi12:
3546       Inst.setOpcode(ARM::t2LDRSHpci);
3547       break;
3548     case ARM::t2LDRBi12:
3549       Inst.setOpcode(ARM::t2LDRBpci);
3550       break;
3551     case ARM::t2LDRSBi12:
3552       Inst.setOpcode(ARM::t2LDRSBpci);
3553       break;
3554     case ARM::t2PLDi12:
3555       Inst.setOpcode(ARM::t2PLDpci);
3556       break;
3557     case ARM::t2PLIi12:
3558       Inst.setOpcode(ARM::t2PLIpci);
3559       break;
3560     default:
3561       return MCDisassembler::Fail;
3562     }
3563     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3564   }
3565 
3566   if (Rt == 15) {
3567     switch (Inst.getOpcode()) {
3568     case ARM::t2LDRSHi12:
3569       return MCDisassembler::Fail;
3570     case ARM::t2LDRHi12:
3571       Inst.setOpcode(ARM::t2PLDWi12);
3572       break;
3573     case ARM::t2LDRSBi12:
3574       Inst.setOpcode(ARM::t2PLIi12);
3575       break;
3576     default:
3577       break;
3578     }
3579   }
3580 
3581   switch (Inst.getOpcode()) {
3582   case ARM::t2PLDi12:
3583     break;
3584   case ARM::t2PLIi12:
3585     if (!hasV7Ops)
3586       return MCDisassembler::Fail;
3587     break;
3588   case ARM::t2PLDWi12:
3589       if (!hasV7Ops || !hasMP)
3590         return MCDisassembler::Fail;
3591       break;
3592   default:
3593     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3594       return MCDisassembler::Fail;
3595   }
3596 
3597   if (!Check(S, DecodeT2AddrModeImm12(Inst, imm, Address, Decoder)))
3598     return MCDisassembler::Fail;
3599   return S;
3600 }
3601 
3602 static DecodeStatus DecodeT2LoadT(MCInst &Inst, unsigned Insn,
3603                                 uint64_t Address, const void* Decoder) {
3604   DecodeStatus S = MCDisassembler::Success;
3605 
3606   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3607   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3608   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3609   imm |= (Rn << 9);
3610 
3611   if (Rn == 15) {
3612     switch (Inst.getOpcode()) {
3613     case ARM::t2LDRT:
3614       Inst.setOpcode(ARM::t2LDRpci);
3615       break;
3616     case ARM::t2LDRBT:
3617       Inst.setOpcode(ARM::t2LDRBpci);
3618       break;
3619     case ARM::t2LDRHT:
3620       Inst.setOpcode(ARM::t2LDRHpci);
3621       break;
3622     case ARM::t2LDRSBT:
3623       Inst.setOpcode(ARM::t2LDRSBpci);
3624       break;
3625     case ARM::t2LDRSHT:
3626       Inst.setOpcode(ARM::t2LDRSHpci);
3627       break;
3628     default:
3629       return MCDisassembler::Fail;
3630     }
3631     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3632   }
3633 
3634   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3635     return MCDisassembler::Fail;
3636   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
3637     return MCDisassembler::Fail;
3638   return S;
3639 }
3640 
3641 static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
3642                                 uint64_t Address, const void* Decoder) {
3643   DecodeStatus S = MCDisassembler::Success;
3644 
3645   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3646   unsigned U = fieldFromInstruction(Insn, 23, 1);
3647   int imm = fieldFromInstruction(Insn, 0, 12);
3648 
3649   const FeatureBitset &featureBits =
3650     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3651 
3652   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3653 
3654   if (Rt == 15) {
3655     switch (Inst.getOpcode()) {
3656       case ARM::t2LDRBpci:
3657       case ARM::t2LDRHpci:
3658         Inst.setOpcode(ARM::t2PLDpci);
3659         break;
3660       case ARM::t2LDRSBpci:
3661         Inst.setOpcode(ARM::t2PLIpci);
3662         break;
3663       case ARM::t2LDRSHpci:
3664         return MCDisassembler::Fail;
3665       default:
3666         break;
3667     }
3668   }
3669 
3670   switch(Inst.getOpcode()) {
3671   case ARM::t2PLDpci:
3672     break;
3673   case ARM::t2PLIpci:
3674     if (!hasV7Ops)
3675       return MCDisassembler::Fail;
3676     break;
3677   default:
3678     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3679       return MCDisassembler::Fail;
3680   }
3681 
3682   if (!U) {
3683     // Special case for #-0.
3684     if (imm == 0)
3685       imm = INT32_MIN;
3686     else
3687       imm = -imm;
3688   }
3689   Inst.addOperand(MCOperand::createImm(imm));
3690 
3691   return S;
3692 }
3693 
3694 static DecodeStatus DecodeT2Imm8S4(MCInst &Inst, unsigned Val,
3695                            uint64_t Address, const void *Decoder) {
3696   if (Val == 0)
3697     Inst.addOperand(MCOperand::createImm(INT32_MIN));
3698   else {
3699     int imm = Val & 0xFF;
3700 
3701     if (!(Val & 0x100)) imm *= -1;
3702     Inst.addOperand(MCOperand::createImm(imm * 4));
3703   }
3704 
3705   return MCDisassembler::Success;
3706 }
3707 
3708 static DecodeStatus DecodeT2AddrModeImm8s4(MCInst &Inst, unsigned Val,
3709                                    uint64_t Address, const void *Decoder) {
3710   DecodeStatus S = MCDisassembler::Success;
3711 
3712   unsigned Rn = fieldFromInstruction(Val, 9, 4);
3713   unsigned imm = fieldFromInstruction(Val, 0, 9);
3714 
3715   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3716     return MCDisassembler::Fail;
3717   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
3718     return MCDisassembler::Fail;
3719 
3720   return S;
3721 }
3722 
3723 static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst &Inst,unsigned Val,
3724                                    uint64_t Address, const void *Decoder) {
3725   DecodeStatus S = MCDisassembler::Success;
3726 
3727   unsigned Rn = fieldFromInstruction(Val, 8, 4);
3728   unsigned imm = fieldFromInstruction(Val, 0, 8);
3729 
3730   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
3731     return MCDisassembler::Fail;
3732 
3733   Inst.addOperand(MCOperand::createImm(imm));
3734 
3735   return S;
3736 }
3737 
3738 static DecodeStatus DecodeT2Imm8(MCInst &Inst, unsigned Val,
3739                          uint64_t Address, const void *Decoder) {
3740   int imm = Val & 0xFF;
3741   if (Val == 0)
3742     imm = INT32_MIN;
3743   else if (!(Val & 0x100))
3744     imm *= -1;
3745   Inst.addOperand(MCOperand::createImm(imm));
3746 
3747   return MCDisassembler::Success;
3748 }
3749 
3750 static DecodeStatus DecodeT2AddrModeImm8(MCInst &Inst, unsigned Val,
3751                                  uint64_t Address, const void *Decoder) {
3752   DecodeStatus S = MCDisassembler::Success;
3753 
3754   unsigned Rn = fieldFromInstruction(Val, 9, 4);
3755   unsigned imm = fieldFromInstruction(Val, 0, 9);
3756 
3757   // Thumb stores cannot use PC as dest register.
3758   switch (Inst.getOpcode()) {
3759   case ARM::t2STRT:
3760   case ARM::t2STRBT:
3761   case ARM::t2STRHT:
3762   case ARM::t2STRi8:
3763   case ARM::t2STRHi8:
3764   case ARM::t2STRBi8:
3765     if (Rn == 15)
3766       return MCDisassembler::Fail;
3767     break;
3768   default:
3769     break;
3770   }
3771 
3772   // Some instructions always use an additive offset.
3773   switch (Inst.getOpcode()) {
3774     case ARM::t2LDRT:
3775     case ARM::t2LDRBT:
3776     case ARM::t2LDRHT:
3777     case ARM::t2LDRSBT:
3778     case ARM::t2LDRSHT:
3779     case ARM::t2STRT:
3780     case ARM::t2STRBT:
3781     case ARM::t2STRHT:
3782       imm |= 0x100;
3783       break;
3784     default:
3785       break;
3786   }
3787 
3788   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3789     return MCDisassembler::Fail;
3790   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
3791     return MCDisassembler::Fail;
3792 
3793   return S;
3794 }
3795 
3796 static DecodeStatus DecodeT2LdStPre(MCInst &Inst, unsigned Insn,
3797                                     uint64_t Address, const void *Decoder) {
3798   DecodeStatus S = MCDisassembler::Success;
3799 
3800   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3801   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3802   unsigned addr = fieldFromInstruction(Insn, 0, 8);
3803   addr |= fieldFromInstruction(Insn, 9, 1) << 8;
3804   addr |= Rn << 9;
3805   unsigned load = fieldFromInstruction(Insn, 20, 1);
3806 
3807   if (Rn == 15) {
3808     switch (Inst.getOpcode()) {
3809     case ARM::t2LDR_PRE:
3810     case ARM::t2LDR_POST:
3811       Inst.setOpcode(ARM::t2LDRpci);
3812       break;
3813     case ARM::t2LDRB_PRE:
3814     case ARM::t2LDRB_POST:
3815       Inst.setOpcode(ARM::t2LDRBpci);
3816       break;
3817     case ARM::t2LDRH_PRE:
3818     case ARM::t2LDRH_POST:
3819       Inst.setOpcode(ARM::t2LDRHpci);
3820       break;
3821     case ARM::t2LDRSB_PRE:
3822     case ARM::t2LDRSB_POST:
3823       if (Rt == 15)
3824         Inst.setOpcode(ARM::t2PLIpci);
3825       else
3826         Inst.setOpcode(ARM::t2LDRSBpci);
3827       break;
3828     case ARM::t2LDRSH_PRE:
3829     case ARM::t2LDRSH_POST:
3830       Inst.setOpcode(ARM::t2LDRSHpci);
3831       break;
3832     default:
3833       return MCDisassembler::Fail;
3834     }
3835     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3836   }
3837 
3838   if (!load) {
3839     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3840       return MCDisassembler::Fail;
3841   }
3842 
3843   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3844     return MCDisassembler::Fail;
3845 
3846   if (load) {
3847     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3848       return MCDisassembler::Fail;
3849   }
3850 
3851   if (!Check(S, DecodeT2AddrModeImm8(Inst, addr, Address, Decoder)))
3852     return MCDisassembler::Fail;
3853 
3854   return S;
3855 }
3856 
3857 static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
3858                                   uint64_t Address, const void *Decoder) {
3859   DecodeStatus S = MCDisassembler::Success;
3860 
3861   unsigned Rn = fieldFromInstruction(Val, 13, 4);
3862   unsigned imm = fieldFromInstruction(Val, 0, 12);
3863 
3864   // Thumb stores cannot use PC as dest register.
3865   switch (Inst.getOpcode()) {
3866   case ARM::t2STRi12:
3867   case ARM::t2STRBi12:
3868   case ARM::t2STRHi12:
3869     if (Rn == 15)
3870       return MCDisassembler::Fail;
3871     break;
3872   default:
3873     break;
3874   }
3875 
3876   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3877     return MCDisassembler::Fail;
3878   Inst.addOperand(MCOperand::createImm(imm));
3879 
3880   return S;
3881 }
3882 
3883 static DecodeStatus DecodeThumbAddSPImm(MCInst &Inst, uint16_t Insn,
3884                                 uint64_t Address, const void *Decoder) {
3885   unsigned imm = fieldFromInstruction(Insn, 0, 7);
3886 
3887   Inst.addOperand(MCOperand::createReg(ARM::SP));
3888   Inst.addOperand(MCOperand::createReg(ARM::SP));
3889   Inst.addOperand(MCOperand::createImm(imm));
3890 
3891   return MCDisassembler::Success;
3892 }
3893 
3894 static DecodeStatus DecodeThumbAddSPReg(MCInst &Inst, uint16_t Insn,
3895                                 uint64_t Address, const void *Decoder) {
3896   DecodeStatus S = MCDisassembler::Success;
3897 
3898   if (Inst.getOpcode() == ARM::tADDrSP) {
3899     unsigned Rdm = fieldFromInstruction(Insn, 0, 3);
3900     Rdm |= fieldFromInstruction(Insn, 7, 1) << 3;
3901 
3902     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
3903     return MCDisassembler::Fail;
3904     Inst.addOperand(MCOperand::createReg(ARM::SP));
3905     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
3906     return MCDisassembler::Fail;
3907   } else if (Inst.getOpcode() == ARM::tADDspr) {
3908     unsigned Rm = fieldFromInstruction(Insn, 3, 4);
3909 
3910     Inst.addOperand(MCOperand::createReg(ARM::SP));
3911     Inst.addOperand(MCOperand::createReg(ARM::SP));
3912     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3913     return MCDisassembler::Fail;
3914   }
3915 
3916   return S;
3917 }
3918 
3919 static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
3920                            uint64_t Address, const void *Decoder) {
3921   unsigned imod = fieldFromInstruction(Insn, 4, 1) | 0x2;
3922   unsigned flags = fieldFromInstruction(Insn, 0, 3);
3923 
3924   Inst.addOperand(MCOperand::createImm(imod));
3925   Inst.addOperand(MCOperand::createImm(flags));
3926 
3927   return MCDisassembler::Success;
3928 }
3929 
3930 static DecodeStatus DecodePostIdxReg(MCInst &Inst, unsigned Insn,
3931                              uint64_t Address, const void *Decoder) {
3932   DecodeStatus S = MCDisassembler::Success;
3933   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3934   unsigned add = fieldFromInstruction(Insn, 4, 1);
3935 
3936   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
3937     return MCDisassembler::Fail;
3938   Inst.addOperand(MCOperand::createImm(add));
3939 
3940   return S;
3941 }
3942 
3943 static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Val,
3944                                  uint64_t Address, const void *Decoder) {
3945   // Val is passed in as S:J1:J2:imm10H:imm10L:'0'
3946   // Note only one trailing zero not two.  Also the J1 and J2 values are from
3947   // the encoded instruction.  So here change to I1 and I2 values via:
3948   // I1 = NOT(J1 EOR S);
3949   // I2 = NOT(J2 EOR S);
3950   // and build the imm32 with two trailing zeros as documented:
3951   // imm32 = SignExtend(S:I1:I2:imm10H:imm10L:'00', 32);
3952   unsigned S = (Val >> 23) & 1;
3953   unsigned J1 = (Val >> 22) & 1;
3954   unsigned J2 = (Val >> 21) & 1;
3955   unsigned I1 = !(J1 ^ S);
3956   unsigned I2 = !(J2 ^ S);
3957   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
3958   int imm32 = SignExtend32<25>(tmp << 1);
3959 
3960   if (!tryAddingSymbolicOperand(Address,
3961                                 (Address & ~2u) + imm32 + 4,
3962                                 true, 4, Inst, Decoder))
3963     Inst.addOperand(MCOperand::createImm(imm32));
3964   return MCDisassembler::Success;
3965 }
3966 
3967 static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Val,
3968                               uint64_t Address, const void *Decoder) {
3969   if (Val == 0xA || Val == 0xB)
3970     return MCDisassembler::Fail;
3971 
3972   const FeatureBitset &featureBits =
3973     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3974 
3975   if (featureBits[ARM::HasV8Ops] && !(Val == 14 || Val == 15))
3976     return MCDisassembler::Fail;
3977 
3978   Inst.addOperand(MCOperand::createImm(Val));
3979   return MCDisassembler::Success;
3980 }
3981 
3982 static DecodeStatus
3983 DecodeThumbTableBranch(MCInst &Inst, unsigned Insn,
3984                        uint64_t Address, const void *Decoder) {
3985   DecodeStatus S = MCDisassembler::Success;
3986 
3987   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3988   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3989 
3990   if (Rn == ARM::SP) S = MCDisassembler::SoftFail;
3991   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3992     return MCDisassembler::Fail;
3993   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
3994     return MCDisassembler::Fail;
3995   return S;
3996 }
3997 
3998 static DecodeStatus
3999 DecodeThumb2BCCInstruction(MCInst &Inst, unsigned Insn,
4000                            uint64_t Address, const void *Decoder) {
4001   DecodeStatus S = MCDisassembler::Success;
4002 
4003   unsigned pred = fieldFromInstruction(Insn, 22, 4);
4004   if (pred == 0xE || pred == 0xF) {
4005     unsigned opc = fieldFromInstruction(Insn, 4, 28);
4006     switch (opc) {
4007       default:
4008         return MCDisassembler::Fail;
4009       case 0xf3bf8f4:
4010         Inst.setOpcode(ARM::t2DSB);
4011         break;
4012       case 0xf3bf8f5:
4013         Inst.setOpcode(ARM::t2DMB);
4014         break;
4015       case 0xf3bf8f6:
4016         Inst.setOpcode(ARM::t2ISB);
4017         break;
4018     }
4019 
4020     unsigned imm = fieldFromInstruction(Insn, 0, 4);
4021     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
4022   }
4023 
4024   unsigned brtarget = fieldFromInstruction(Insn, 0, 11) << 1;
4025   brtarget |= fieldFromInstruction(Insn, 11, 1) << 19;
4026   brtarget |= fieldFromInstruction(Insn, 13, 1) << 18;
4027   brtarget |= fieldFromInstruction(Insn, 16, 6) << 12;
4028   brtarget |= fieldFromInstruction(Insn, 26, 1) << 20;
4029 
4030   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
4031     return MCDisassembler::Fail;
4032   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4033     return MCDisassembler::Fail;
4034 
4035   return S;
4036 }
4037 
4038 // Decode a shifted immediate operand.  These basically consist
4039 // of an 8-bit value, and a 4-bit directive that specifies either
4040 // a splat operation or a rotation.
4041 static DecodeStatus DecodeT2SOImm(MCInst &Inst, unsigned Val,
4042                           uint64_t Address, const void *Decoder) {
4043   unsigned ctrl = fieldFromInstruction(Val, 10, 2);
4044   if (ctrl == 0) {
4045     unsigned byte = fieldFromInstruction(Val, 8, 2);
4046     unsigned imm = fieldFromInstruction(Val, 0, 8);
4047     switch (byte) {
4048       case 0:
4049         Inst.addOperand(MCOperand::createImm(imm));
4050         break;
4051       case 1:
4052         Inst.addOperand(MCOperand::createImm((imm << 16) | imm));
4053         break;
4054       case 2:
4055         Inst.addOperand(MCOperand::createImm((imm << 24) | (imm << 8)));
4056         break;
4057       case 3:
4058         Inst.addOperand(MCOperand::createImm((imm << 24) | (imm << 16) |
4059                                              (imm << 8)  |  imm));
4060         break;
4061     }
4062   } else {
4063     unsigned unrot = fieldFromInstruction(Val, 0, 7) | 0x80;
4064     unsigned rot = fieldFromInstruction(Val, 7, 5);
4065     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
4066     Inst.addOperand(MCOperand::createImm(imm));
4067   }
4068 
4069   return MCDisassembler::Success;
4070 }
4071 
4072 static DecodeStatus
4073 DecodeThumbBCCTargetOperand(MCInst &Inst, unsigned Val,
4074                             uint64_t Address, const void *Decoder) {
4075   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<9>(Val<<1) + 4,
4076                                 true, 2, Inst, Decoder))
4077     Inst.addOperand(MCOperand::createImm(SignExtend32<9>(Val << 1)));
4078   return MCDisassembler::Success;
4079 }
4080 
4081 static DecodeStatus DecodeThumbBLTargetOperand(MCInst &Inst, unsigned Val,
4082                                                uint64_t Address,
4083                                                const void *Decoder) {
4084   // Val is passed in as S:J1:J2:imm10:imm11
4085   // Note no trailing zero after imm11.  Also the J1 and J2 values are from
4086   // the encoded instruction.  So here change to I1 and I2 values via:
4087   // I1 = NOT(J1 EOR S);
4088   // I2 = NOT(J2 EOR S);
4089   // and build the imm32 with one trailing zero as documented:
4090   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
4091   unsigned S = (Val >> 23) & 1;
4092   unsigned J1 = (Val >> 22) & 1;
4093   unsigned J2 = (Val >> 21) & 1;
4094   unsigned I1 = !(J1 ^ S);
4095   unsigned I2 = !(J2 ^ S);
4096   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
4097   int imm32 = SignExtend32<25>(tmp << 1);
4098 
4099   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
4100                                 true, 4, Inst, Decoder))
4101     Inst.addOperand(MCOperand::createImm(imm32));
4102   return MCDisassembler::Success;
4103 }
4104 
4105 static DecodeStatus DecodeMemBarrierOption(MCInst &Inst, unsigned Val,
4106                                    uint64_t Address, const void *Decoder) {
4107   if (Val & ~0xf)
4108     return MCDisassembler::Fail;
4109 
4110   Inst.addOperand(MCOperand::createImm(Val));
4111   return MCDisassembler::Success;
4112 }
4113 
4114 static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Val,
4115                                         uint64_t Address, const void *Decoder) {
4116   if (Val & ~0xf)
4117     return MCDisassembler::Fail;
4118 
4119   Inst.addOperand(MCOperand::createImm(Val));
4120   return MCDisassembler::Success;
4121 }
4122 
4123 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val,
4124                           uint64_t Address, const void *Decoder) {
4125   DecodeStatus S = MCDisassembler::Success;
4126   const FeatureBitset &FeatureBits =
4127     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
4128 
4129   if (FeatureBits[ARM::FeatureMClass]) {
4130     unsigned ValLow = Val & 0xff;
4131 
4132     // Validate the SYSm value first.
4133     switch (ValLow) {
4134     case  0: // apsr
4135     case  1: // iapsr
4136     case  2: // eapsr
4137     case  3: // xpsr
4138     case  5: // ipsr
4139     case  6: // epsr
4140     case  7: // iepsr
4141     case  8: // msp
4142     case  9: // psp
4143     case 16: // primask
4144     case 20: // control
4145       break;
4146     case 17: // basepri
4147     case 18: // basepri_max
4148     case 19: // faultmask
4149       if (!(FeatureBits[ARM::HasV7Ops]))
4150         // Values basepri, basepri_max and faultmask are only valid for v7m.
4151         return MCDisassembler::Fail;
4152       break;
4153     case 0x8a: // msplim_ns
4154     case 0x8b: // psplim_ns
4155     case 0x91: // basepri_ns
4156     case 0x93: // faultmask_ns
4157       if (!(FeatureBits[ARM::HasV8MMainlineOps]))
4158         return MCDisassembler::Fail;
4159       LLVM_FALLTHROUGH;
4160     case 10:   // msplim
4161     case 11:   // psplim
4162     case 0x88: // msp_ns
4163     case 0x89: // psp_ns
4164     case 0x90: // primask_ns
4165     case 0x94: // control_ns
4166     case 0x98: // sp_ns
4167       if (!(FeatureBits[ARM::Feature8MSecExt]))
4168         return MCDisassembler::Fail;
4169       break;
4170     default:
4171       // Architecturally defined as unpredictable
4172       S = MCDisassembler::SoftFail;
4173       break;
4174     }
4175 
4176     if (Inst.getOpcode() == ARM::t2MSR_M) {
4177       unsigned Mask = fieldFromInstruction(Val, 10, 2);
4178       if (!(FeatureBits[ARM::HasV7Ops])) {
4179         // The ARMv6-M MSR bits {11-10} can be only 0b10, other values are
4180         // unpredictable.
4181         if (Mask != 2)
4182           S = MCDisassembler::SoftFail;
4183       }
4184       else {
4185         // The ARMv7-M architecture stores an additional 2-bit mask value in
4186         // MSR bits {11-10}. The mask is used only with apsr, iapsr, eapsr and
4187         // xpsr, it has to be 0b10 in other cases. Bit mask{1} indicates if
4188         // the NZCVQ bits should be moved by the instruction. Bit mask{0}
4189         // indicates the move for the GE{3:0} bits, the mask{0} bit can be set
4190         // only if the processor includes the DSP extension.
4191         if (Mask == 0 || (Mask != 2 && ValLow > 3) ||
4192             (!(FeatureBits[ARM::FeatureDSP]) && (Mask & 1)))
4193           S = MCDisassembler::SoftFail;
4194       }
4195     }
4196   } else {
4197     // A/R class
4198     if (Val == 0)
4199       return MCDisassembler::Fail;
4200   }
4201   Inst.addOperand(MCOperand::createImm(Val));
4202   return S;
4203 }
4204 
4205 static DecodeStatus DecodeBankedReg(MCInst &Inst, unsigned Val,
4206                                     uint64_t Address, const void *Decoder) {
4207   unsigned R = fieldFromInstruction(Val, 5, 1);
4208   unsigned SysM = fieldFromInstruction(Val, 0, 5);
4209 
4210   // The table of encodings for these banked registers comes from B9.2.3 of the
4211   // ARM ARM. There are patterns, but nothing regular enough to make this logic
4212   // neater. So by fiat, these values are UNPREDICTABLE:
4213   if (!ARMBankedReg::lookupBankedRegByEncoding((R << 5) | SysM))
4214     return MCDisassembler::Fail;
4215 
4216   Inst.addOperand(MCOperand::createImm(Val));
4217   return MCDisassembler::Success;
4218 }
4219 
4220 static DecodeStatus DecodeDoubleRegLoad(MCInst &Inst, unsigned Insn,
4221                                         uint64_t Address, const void *Decoder) {
4222   DecodeStatus S = MCDisassembler::Success;
4223 
4224   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4225   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4226   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4227 
4228   if (Rn == 0xF)
4229     S = MCDisassembler::SoftFail;
4230 
4231   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
4232     return MCDisassembler::Fail;
4233   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4234     return MCDisassembler::Fail;
4235   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4236     return MCDisassembler::Fail;
4237 
4238   return S;
4239 }
4240 
4241 static DecodeStatus DecodeDoubleRegStore(MCInst &Inst, unsigned Insn,
4242                                          uint64_t Address,
4243                                          const void *Decoder) {
4244   DecodeStatus S = MCDisassembler::Success;
4245 
4246   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4247   unsigned Rt = fieldFromInstruction(Insn, 0, 4);
4248   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4249   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4250 
4251   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
4252     return MCDisassembler::Fail;
4253 
4254   if (Rn == 0xF || Rd == Rn || Rd == Rt || Rd == Rt+1)
4255     S = MCDisassembler::SoftFail;
4256 
4257   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
4258     return MCDisassembler::Fail;
4259   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4260     return MCDisassembler::Fail;
4261   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4262     return MCDisassembler::Fail;
4263 
4264   return S;
4265 }
4266 
4267 static DecodeStatus DecodeLDRPreImm(MCInst &Inst, unsigned Insn,
4268                             uint64_t Address, const void *Decoder) {
4269   DecodeStatus S = MCDisassembler::Success;
4270 
4271   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4272   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4273   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4274   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4275   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4276   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4277 
4278   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4279 
4280   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4281     return MCDisassembler::Fail;
4282   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4283     return MCDisassembler::Fail;
4284   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
4285     return MCDisassembler::Fail;
4286   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4287     return MCDisassembler::Fail;
4288 
4289   return S;
4290 }
4291 
4292 static DecodeStatus DecodeLDRPreReg(MCInst &Inst, unsigned Insn,
4293                             uint64_t Address, const void *Decoder) {
4294   DecodeStatus S = MCDisassembler::Success;
4295 
4296   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4297   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4298   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4299   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4300   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4301   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4302   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4303 
4304   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4305   if (Rm == 0xF) S = MCDisassembler::SoftFail;
4306 
4307   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4308     return MCDisassembler::Fail;
4309   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4310     return MCDisassembler::Fail;
4311   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
4312     return MCDisassembler::Fail;
4313   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4314     return MCDisassembler::Fail;
4315 
4316   return S;
4317 }
4318 
4319 static DecodeStatus DecodeSTRPreImm(MCInst &Inst, unsigned Insn,
4320                             uint64_t Address, const void *Decoder) {
4321   DecodeStatus S = MCDisassembler::Success;
4322 
4323   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4324   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4325   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4326   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4327   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4328   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4329 
4330   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4331 
4332   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4333     return MCDisassembler::Fail;
4334   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4335     return MCDisassembler::Fail;
4336   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
4337     return MCDisassembler::Fail;
4338   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4339     return MCDisassembler::Fail;
4340 
4341   return S;
4342 }
4343 
4344 static DecodeStatus DecodeSTRPreReg(MCInst &Inst, unsigned Insn,
4345                             uint64_t Address, const void *Decoder) {
4346   DecodeStatus S = MCDisassembler::Success;
4347 
4348   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4349   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4350   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4351   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4352   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4353   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4354 
4355   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4356 
4357   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4358     return MCDisassembler::Fail;
4359   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4360     return MCDisassembler::Fail;
4361   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
4362     return MCDisassembler::Fail;
4363   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4364     return MCDisassembler::Fail;
4365 
4366   return S;
4367 }
4368 
4369 static DecodeStatus DecodeVLD1LN(MCInst &Inst, unsigned Insn,
4370                          uint64_t Address, const void *Decoder) {
4371   DecodeStatus S = MCDisassembler::Success;
4372 
4373   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4374   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4375   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4376   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4377   unsigned size = fieldFromInstruction(Insn, 10, 2);
4378 
4379   unsigned align = 0;
4380   unsigned index = 0;
4381   switch (size) {
4382     default:
4383       return MCDisassembler::Fail;
4384     case 0:
4385       if (fieldFromInstruction(Insn, 4, 1))
4386         return MCDisassembler::Fail; // UNDEFINED
4387       index = fieldFromInstruction(Insn, 5, 3);
4388       break;
4389     case 1:
4390       if (fieldFromInstruction(Insn, 5, 1))
4391         return MCDisassembler::Fail; // UNDEFINED
4392       index = fieldFromInstruction(Insn, 6, 2);
4393       if (fieldFromInstruction(Insn, 4, 1))
4394         align = 2;
4395       break;
4396     case 2:
4397       if (fieldFromInstruction(Insn, 6, 1))
4398         return MCDisassembler::Fail; // UNDEFINED
4399       index = fieldFromInstruction(Insn, 7, 1);
4400 
4401       switch (fieldFromInstruction(Insn, 4, 2)) {
4402         case 0 :
4403           align = 0; break;
4404         case 3:
4405           align = 4; break;
4406         default:
4407           return MCDisassembler::Fail;
4408       }
4409       break;
4410   }
4411 
4412   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4413     return MCDisassembler::Fail;
4414   if (Rm != 0xF) { // Writeback
4415     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4416       return MCDisassembler::Fail;
4417   }
4418   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4419     return MCDisassembler::Fail;
4420   Inst.addOperand(MCOperand::createImm(align));
4421   if (Rm != 0xF) {
4422     if (Rm != 0xD) {
4423       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4424         return MCDisassembler::Fail;
4425     } else
4426       Inst.addOperand(MCOperand::createReg(0));
4427   }
4428 
4429   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4430     return MCDisassembler::Fail;
4431   Inst.addOperand(MCOperand::createImm(index));
4432 
4433   return S;
4434 }
4435 
4436 static DecodeStatus DecodeVST1LN(MCInst &Inst, unsigned Insn,
4437                          uint64_t Address, const void *Decoder) {
4438   DecodeStatus S = MCDisassembler::Success;
4439 
4440   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4441   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4442   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4443   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4444   unsigned size = fieldFromInstruction(Insn, 10, 2);
4445 
4446   unsigned align = 0;
4447   unsigned index = 0;
4448   switch (size) {
4449     default:
4450       return MCDisassembler::Fail;
4451     case 0:
4452       if (fieldFromInstruction(Insn, 4, 1))
4453         return MCDisassembler::Fail; // UNDEFINED
4454       index = fieldFromInstruction(Insn, 5, 3);
4455       break;
4456     case 1:
4457       if (fieldFromInstruction(Insn, 5, 1))
4458         return MCDisassembler::Fail; // UNDEFINED
4459       index = fieldFromInstruction(Insn, 6, 2);
4460       if (fieldFromInstruction(Insn, 4, 1))
4461         align = 2;
4462       break;
4463     case 2:
4464       if (fieldFromInstruction(Insn, 6, 1))
4465         return MCDisassembler::Fail; // UNDEFINED
4466       index = fieldFromInstruction(Insn, 7, 1);
4467 
4468       switch (fieldFromInstruction(Insn, 4, 2)) {
4469         case 0:
4470           align = 0; break;
4471         case 3:
4472           align = 4; break;
4473         default:
4474           return MCDisassembler::Fail;
4475       }
4476       break;
4477   }
4478 
4479   if (Rm != 0xF) { // Writeback
4480     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4481     return MCDisassembler::Fail;
4482   }
4483   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4484     return MCDisassembler::Fail;
4485   Inst.addOperand(MCOperand::createImm(align));
4486   if (Rm != 0xF) {
4487     if (Rm != 0xD) {
4488       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4489     return MCDisassembler::Fail;
4490     } else
4491       Inst.addOperand(MCOperand::createReg(0));
4492   }
4493 
4494   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4495     return MCDisassembler::Fail;
4496   Inst.addOperand(MCOperand::createImm(index));
4497 
4498   return S;
4499 }
4500 
4501 static DecodeStatus DecodeVLD2LN(MCInst &Inst, unsigned Insn,
4502                          uint64_t Address, const void *Decoder) {
4503   DecodeStatus S = MCDisassembler::Success;
4504 
4505   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4506   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4507   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4508   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4509   unsigned size = fieldFromInstruction(Insn, 10, 2);
4510 
4511   unsigned align = 0;
4512   unsigned index = 0;
4513   unsigned inc = 1;
4514   switch (size) {
4515     default:
4516       return MCDisassembler::Fail;
4517     case 0:
4518       index = fieldFromInstruction(Insn, 5, 3);
4519       if (fieldFromInstruction(Insn, 4, 1))
4520         align = 2;
4521       break;
4522     case 1:
4523       index = fieldFromInstruction(Insn, 6, 2);
4524       if (fieldFromInstruction(Insn, 4, 1))
4525         align = 4;
4526       if (fieldFromInstruction(Insn, 5, 1))
4527         inc = 2;
4528       break;
4529     case 2:
4530       if (fieldFromInstruction(Insn, 5, 1))
4531         return MCDisassembler::Fail; // UNDEFINED
4532       index = fieldFromInstruction(Insn, 7, 1);
4533       if (fieldFromInstruction(Insn, 4, 1) != 0)
4534         align = 8;
4535       if (fieldFromInstruction(Insn, 6, 1))
4536         inc = 2;
4537       break;
4538   }
4539 
4540   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4541     return MCDisassembler::Fail;
4542   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4543     return MCDisassembler::Fail;
4544   if (Rm != 0xF) { // Writeback
4545     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4546       return MCDisassembler::Fail;
4547   }
4548   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4549     return MCDisassembler::Fail;
4550   Inst.addOperand(MCOperand::createImm(align));
4551   if (Rm != 0xF) {
4552     if (Rm != 0xD) {
4553       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4554         return MCDisassembler::Fail;
4555     } else
4556       Inst.addOperand(MCOperand::createReg(0));
4557   }
4558 
4559   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4560     return MCDisassembler::Fail;
4561   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4562     return MCDisassembler::Fail;
4563   Inst.addOperand(MCOperand::createImm(index));
4564 
4565   return S;
4566 }
4567 
4568 static DecodeStatus DecodeVST2LN(MCInst &Inst, unsigned Insn,
4569                          uint64_t Address, const void *Decoder) {
4570   DecodeStatus S = MCDisassembler::Success;
4571 
4572   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4573   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4574   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4575   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4576   unsigned size = fieldFromInstruction(Insn, 10, 2);
4577 
4578   unsigned align = 0;
4579   unsigned index = 0;
4580   unsigned inc = 1;
4581   switch (size) {
4582     default:
4583       return MCDisassembler::Fail;
4584     case 0:
4585       index = fieldFromInstruction(Insn, 5, 3);
4586       if (fieldFromInstruction(Insn, 4, 1))
4587         align = 2;
4588       break;
4589     case 1:
4590       index = fieldFromInstruction(Insn, 6, 2);
4591       if (fieldFromInstruction(Insn, 4, 1))
4592         align = 4;
4593       if (fieldFromInstruction(Insn, 5, 1))
4594         inc = 2;
4595       break;
4596     case 2:
4597       if (fieldFromInstruction(Insn, 5, 1))
4598         return MCDisassembler::Fail; // UNDEFINED
4599       index = fieldFromInstruction(Insn, 7, 1);
4600       if (fieldFromInstruction(Insn, 4, 1) != 0)
4601         align = 8;
4602       if (fieldFromInstruction(Insn, 6, 1))
4603         inc = 2;
4604       break;
4605   }
4606 
4607   if (Rm != 0xF) { // Writeback
4608     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4609       return MCDisassembler::Fail;
4610   }
4611   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4612     return MCDisassembler::Fail;
4613   Inst.addOperand(MCOperand::createImm(align));
4614   if (Rm != 0xF) {
4615     if (Rm != 0xD) {
4616       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4617         return MCDisassembler::Fail;
4618     } else
4619       Inst.addOperand(MCOperand::createReg(0));
4620   }
4621 
4622   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4623     return MCDisassembler::Fail;
4624   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4625     return MCDisassembler::Fail;
4626   Inst.addOperand(MCOperand::createImm(index));
4627 
4628   return S;
4629 }
4630 
4631 static DecodeStatus DecodeVLD3LN(MCInst &Inst, unsigned Insn,
4632                          uint64_t Address, const void *Decoder) {
4633   DecodeStatus S = MCDisassembler::Success;
4634 
4635   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4636   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4637   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4638   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4639   unsigned size = fieldFromInstruction(Insn, 10, 2);
4640 
4641   unsigned align = 0;
4642   unsigned index = 0;
4643   unsigned inc = 1;
4644   switch (size) {
4645     default:
4646       return MCDisassembler::Fail;
4647     case 0:
4648       if (fieldFromInstruction(Insn, 4, 1))
4649         return MCDisassembler::Fail; // UNDEFINED
4650       index = fieldFromInstruction(Insn, 5, 3);
4651       break;
4652     case 1:
4653       if (fieldFromInstruction(Insn, 4, 1))
4654         return MCDisassembler::Fail; // UNDEFINED
4655       index = fieldFromInstruction(Insn, 6, 2);
4656       if (fieldFromInstruction(Insn, 5, 1))
4657         inc = 2;
4658       break;
4659     case 2:
4660       if (fieldFromInstruction(Insn, 4, 2))
4661         return MCDisassembler::Fail; // UNDEFINED
4662       index = fieldFromInstruction(Insn, 7, 1);
4663       if (fieldFromInstruction(Insn, 6, 1))
4664         inc = 2;
4665       break;
4666   }
4667 
4668   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4669     return MCDisassembler::Fail;
4670   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4671     return MCDisassembler::Fail;
4672   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4673     return MCDisassembler::Fail;
4674 
4675   if (Rm != 0xF) { // Writeback
4676     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4677     return MCDisassembler::Fail;
4678   }
4679   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4680     return MCDisassembler::Fail;
4681   Inst.addOperand(MCOperand::createImm(align));
4682   if (Rm != 0xF) {
4683     if (Rm != 0xD) {
4684       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4685     return MCDisassembler::Fail;
4686     } else
4687       Inst.addOperand(MCOperand::createReg(0));
4688   }
4689 
4690   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4691     return MCDisassembler::Fail;
4692   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4693     return MCDisassembler::Fail;
4694   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4695     return MCDisassembler::Fail;
4696   Inst.addOperand(MCOperand::createImm(index));
4697 
4698   return S;
4699 }
4700 
4701 static DecodeStatus DecodeVST3LN(MCInst &Inst, unsigned Insn,
4702                          uint64_t Address, const void *Decoder) {
4703   DecodeStatus S = MCDisassembler::Success;
4704 
4705   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4706   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4707   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4708   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4709   unsigned size = fieldFromInstruction(Insn, 10, 2);
4710 
4711   unsigned align = 0;
4712   unsigned index = 0;
4713   unsigned inc = 1;
4714   switch (size) {
4715     default:
4716       return MCDisassembler::Fail;
4717     case 0:
4718       if (fieldFromInstruction(Insn, 4, 1))
4719         return MCDisassembler::Fail; // UNDEFINED
4720       index = fieldFromInstruction(Insn, 5, 3);
4721       break;
4722     case 1:
4723       if (fieldFromInstruction(Insn, 4, 1))
4724         return MCDisassembler::Fail; // UNDEFINED
4725       index = fieldFromInstruction(Insn, 6, 2);
4726       if (fieldFromInstruction(Insn, 5, 1))
4727         inc = 2;
4728       break;
4729     case 2:
4730       if (fieldFromInstruction(Insn, 4, 2))
4731         return MCDisassembler::Fail; // UNDEFINED
4732       index = fieldFromInstruction(Insn, 7, 1);
4733       if (fieldFromInstruction(Insn, 6, 1))
4734         inc = 2;
4735       break;
4736   }
4737 
4738   if (Rm != 0xF) { // Writeback
4739     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4740     return MCDisassembler::Fail;
4741   }
4742   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4743     return MCDisassembler::Fail;
4744   Inst.addOperand(MCOperand::createImm(align));
4745   if (Rm != 0xF) {
4746     if (Rm != 0xD) {
4747       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4748     return MCDisassembler::Fail;
4749     } else
4750       Inst.addOperand(MCOperand::createReg(0));
4751   }
4752 
4753   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4754     return MCDisassembler::Fail;
4755   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4756     return MCDisassembler::Fail;
4757   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4758     return MCDisassembler::Fail;
4759   Inst.addOperand(MCOperand::createImm(index));
4760 
4761   return S;
4762 }
4763 
4764 static DecodeStatus DecodeVLD4LN(MCInst &Inst, unsigned Insn,
4765                          uint64_t Address, const void *Decoder) {
4766   DecodeStatus S = MCDisassembler::Success;
4767 
4768   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4769   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4770   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4771   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4772   unsigned size = fieldFromInstruction(Insn, 10, 2);
4773 
4774   unsigned align = 0;
4775   unsigned index = 0;
4776   unsigned inc = 1;
4777   switch (size) {
4778     default:
4779       return MCDisassembler::Fail;
4780     case 0:
4781       if (fieldFromInstruction(Insn, 4, 1))
4782         align = 4;
4783       index = fieldFromInstruction(Insn, 5, 3);
4784       break;
4785     case 1:
4786       if (fieldFromInstruction(Insn, 4, 1))
4787         align = 8;
4788       index = fieldFromInstruction(Insn, 6, 2);
4789       if (fieldFromInstruction(Insn, 5, 1))
4790         inc = 2;
4791       break;
4792     case 2:
4793       switch (fieldFromInstruction(Insn, 4, 2)) {
4794         case 0:
4795           align = 0; break;
4796         case 3:
4797           return MCDisassembler::Fail;
4798         default:
4799           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
4800       }
4801 
4802       index = fieldFromInstruction(Insn, 7, 1);
4803       if (fieldFromInstruction(Insn, 6, 1))
4804         inc = 2;
4805       break;
4806   }
4807 
4808   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4809     return MCDisassembler::Fail;
4810   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4811     return MCDisassembler::Fail;
4812   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4813     return MCDisassembler::Fail;
4814   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
4815     return MCDisassembler::Fail;
4816 
4817   if (Rm != 0xF) { // Writeback
4818     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4819       return MCDisassembler::Fail;
4820   }
4821   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4822     return MCDisassembler::Fail;
4823   Inst.addOperand(MCOperand::createImm(align));
4824   if (Rm != 0xF) {
4825     if (Rm != 0xD) {
4826       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4827         return MCDisassembler::Fail;
4828     } else
4829       Inst.addOperand(MCOperand::createReg(0));
4830   }
4831 
4832   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4833     return MCDisassembler::Fail;
4834   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4835     return MCDisassembler::Fail;
4836   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4837     return MCDisassembler::Fail;
4838   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
4839     return MCDisassembler::Fail;
4840   Inst.addOperand(MCOperand::createImm(index));
4841 
4842   return S;
4843 }
4844 
4845 static DecodeStatus DecodeVST4LN(MCInst &Inst, unsigned Insn,
4846                          uint64_t Address, const void *Decoder) {
4847   DecodeStatus S = MCDisassembler::Success;
4848 
4849   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4850   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4851   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4852   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4853   unsigned size = fieldFromInstruction(Insn, 10, 2);
4854 
4855   unsigned align = 0;
4856   unsigned index = 0;
4857   unsigned inc = 1;
4858   switch (size) {
4859     default:
4860       return MCDisassembler::Fail;
4861     case 0:
4862       if (fieldFromInstruction(Insn, 4, 1))
4863         align = 4;
4864       index = fieldFromInstruction(Insn, 5, 3);
4865       break;
4866     case 1:
4867       if (fieldFromInstruction(Insn, 4, 1))
4868         align = 8;
4869       index = fieldFromInstruction(Insn, 6, 2);
4870       if (fieldFromInstruction(Insn, 5, 1))
4871         inc = 2;
4872       break;
4873     case 2:
4874       switch (fieldFromInstruction(Insn, 4, 2)) {
4875         case 0:
4876           align = 0; break;
4877         case 3:
4878           return MCDisassembler::Fail;
4879         default:
4880           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
4881       }
4882 
4883       index = fieldFromInstruction(Insn, 7, 1);
4884       if (fieldFromInstruction(Insn, 6, 1))
4885         inc = 2;
4886       break;
4887   }
4888 
4889   if (Rm != 0xF) { // Writeback
4890     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4891     return MCDisassembler::Fail;
4892   }
4893   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4894     return MCDisassembler::Fail;
4895   Inst.addOperand(MCOperand::createImm(align));
4896   if (Rm != 0xF) {
4897     if (Rm != 0xD) {
4898       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4899     return MCDisassembler::Fail;
4900     } else
4901       Inst.addOperand(MCOperand::createReg(0));
4902   }
4903 
4904   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4905     return MCDisassembler::Fail;
4906   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4907     return MCDisassembler::Fail;
4908   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4909     return MCDisassembler::Fail;
4910   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
4911     return MCDisassembler::Fail;
4912   Inst.addOperand(MCOperand::createImm(index));
4913 
4914   return S;
4915 }
4916 
4917 static DecodeStatus DecodeVMOVSRR(MCInst &Inst, unsigned Insn,
4918                                   uint64_t Address, const void *Decoder) {
4919   DecodeStatus S = MCDisassembler::Success;
4920   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
4921   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
4922   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
4923   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4924   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
4925 
4926   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
4927     S = MCDisassembler::SoftFail;
4928 
4929   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
4930     return MCDisassembler::Fail;
4931   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
4932     return MCDisassembler::Fail;
4933   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
4934     return MCDisassembler::Fail;
4935   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
4936     return MCDisassembler::Fail;
4937   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4938     return MCDisassembler::Fail;
4939 
4940   return S;
4941 }
4942 
4943 static DecodeStatus DecodeVMOVRRS(MCInst &Inst, unsigned Insn,
4944                                   uint64_t Address, const void *Decoder) {
4945   DecodeStatus S = MCDisassembler::Success;
4946   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
4947   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
4948   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
4949   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4950   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
4951 
4952   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
4953     S = MCDisassembler::SoftFail;
4954 
4955   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
4956     return MCDisassembler::Fail;
4957   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
4958     return MCDisassembler::Fail;
4959   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
4960     return MCDisassembler::Fail;
4961   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
4962     return MCDisassembler::Fail;
4963   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4964     return MCDisassembler::Fail;
4965 
4966   return S;
4967 }
4968 
4969 static DecodeStatus DecodeIT(MCInst &Inst, unsigned Insn,
4970                              uint64_t Address, const void *Decoder) {
4971   DecodeStatus S = MCDisassembler::Success;
4972   unsigned pred = fieldFromInstruction(Insn, 4, 4);
4973   unsigned mask = fieldFromInstruction(Insn, 0, 4);
4974 
4975   if (pred == 0xF) {
4976     pred = 0xE;
4977     S = MCDisassembler::SoftFail;
4978   }
4979 
4980   if (mask == 0x0)
4981     return MCDisassembler::Fail;
4982 
4983   Inst.addOperand(MCOperand::createImm(pred));
4984   Inst.addOperand(MCOperand::createImm(mask));
4985   return S;
4986 }
4987 
4988 static DecodeStatus
4989 DecodeT2LDRDPreInstruction(MCInst &Inst, unsigned Insn,
4990                            uint64_t Address, const void *Decoder) {
4991   DecodeStatus S = MCDisassembler::Success;
4992 
4993   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4994   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
4995   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4996   unsigned addr = fieldFromInstruction(Insn, 0, 8);
4997   unsigned W = fieldFromInstruction(Insn, 21, 1);
4998   unsigned U = fieldFromInstruction(Insn, 23, 1);
4999   unsigned P = fieldFromInstruction(Insn, 24, 1);
5000   bool writeback = (W == 1) | (P == 0);
5001 
5002   addr |= (U << 8) | (Rn << 9);
5003 
5004   if (writeback && (Rn == Rt || Rn == Rt2))
5005     Check(S, MCDisassembler::SoftFail);
5006   if (Rt == Rt2)
5007     Check(S, MCDisassembler::SoftFail);
5008 
5009   // Rt
5010   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
5011     return MCDisassembler::Fail;
5012   // Rt2
5013   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
5014     return MCDisassembler::Fail;
5015   // Writeback operand
5016   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
5017     return MCDisassembler::Fail;
5018   // addr
5019   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
5020     return MCDisassembler::Fail;
5021 
5022   return S;
5023 }
5024 
5025 static DecodeStatus
5026 DecodeT2STRDPreInstruction(MCInst &Inst, unsigned Insn,
5027                            uint64_t Address, const void *Decoder) {
5028   DecodeStatus S = MCDisassembler::Success;
5029 
5030   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
5031   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
5032   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5033   unsigned addr = fieldFromInstruction(Insn, 0, 8);
5034   unsigned W = fieldFromInstruction(Insn, 21, 1);
5035   unsigned U = fieldFromInstruction(Insn, 23, 1);
5036   unsigned P = fieldFromInstruction(Insn, 24, 1);
5037   bool writeback = (W == 1) | (P == 0);
5038 
5039   addr |= (U << 8) | (Rn << 9);
5040 
5041   if (writeback && (Rn == Rt || Rn == Rt2))
5042     Check(S, MCDisassembler::SoftFail);
5043 
5044   // Writeback operand
5045   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
5046     return MCDisassembler::Fail;
5047   // Rt
5048   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
5049     return MCDisassembler::Fail;
5050   // Rt2
5051   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
5052     return MCDisassembler::Fail;
5053   // addr
5054   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
5055     return MCDisassembler::Fail;
5056 
5057   return S;
5058 }
5059 
5060 static DecodeStatus DecodeT2Adr(MCInst &Inst, uint32_t Insn,
5061                                 uint64_t Address, const void *Decoder) {
5062   unsigned sign1 = fieldFromInstruction(Insn, 21, 1);
5063   unsigned sign2 = fieldFromInstruction(Insn, 23, 1);
5064   if (sign1 != sign2) return MCDisassembler::Fail;
5065 
5066   unsigned Val = fieldFromInstruction(Insn, 0, 8);
5067   Val |= fieldFromInstruction(Insn, 12, 3) << 8;
5068   Val |= fieldFromInstruction(Insn, 26, 1) << 11;
5069   Val |= sign1 << 12;
5070   Inst.addOperand(MCOperand::createImm(SignExtend32<13>(Val)));
5071 
5072   return MCDisassembler::Success;
5073 }
5074 
5075 static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, uint32_t Val,
5076                                               uint64_t Address,
5077                                               const void *Decoder) {
5078   DecodeStatus S = MCDisassembler::Success;
5079 
5080   // Shift of "asr #32" is not allowed in Thumb2 mode.
5081   if (Val == 0x20) S = MCDisassembler::Fail;
5082   Inst.addOperand(MCOperand::createImm(Val));
5083   return S;
5084 }
5085 
5086 static DecodeStatus DecodeSwap(MCInst &Inst, unsigned Insn,
5087                                uint64_t Address, const void *Decoder) {
5088   unsigned Rt   = fieldFromInstruction(Insn, 12, 4);
5089   unsigned Rt2  = fieldFromInstruction(Insn, 0,  4);
5090   unsigned Rn   = fieldFromInstruction(Insn, 16, 4);
5091   unsigned pred = fieldFromInstruction(Insn, 28, 4);
5092 
5093   if (pred == 0xF)
5094     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
5095 
5096   DecodeStatus S = MCDisassembler::Success;
5097 
5098   if (Rt == Rn || Rn == Rt2)
5099     S = MCDisassembler::SoftFail;
5100 
5101   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5102     return MCDisassembler::Fail;
5103   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5104     return MCDisassembler::Fail;
5105   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
5106     return MCDisassembler::Fail;
5107   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5108     return MCDisassembler::Fail;
5109 
5110   return S;
5111 }
5112 
5113 static DecodeStatus DecodeVCVTD(MCInst &Inst, unsigned Insn,
5114                                 uint64_t Address, const void *Decoder) {
5115   const FeatureBitset &featureBits =
5116       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5117   bool hasFullFP16 = featureBits[ARM::FeatureFullFP16];
5118 
5119   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5120   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5121   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5122   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5123   unsigned imm = fieldFromInstruction(Insn, 16, 6);
5124   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
5125   unsigned op = fieldFromInstruction(Insn, 5, 1);
5126 
5127   DecodeStatus S = MCDisassembler::Success;
5128 
5129   // If the top 3 bits of imm are clear, this is a VMOV (immediate)
5130   if (!(imm & 0x38)) {
5131     if (cmode == 0xF) {
5132       if (op == 1) return MCDisassembler::Fail;
5133       Inst.setOpcode(ARM::VMOVv2f32);
5134     }
5135     if (hasFullFP16) {
5136       if (cmode == 0xE) {
5137         if (op == 1) {
5138           Inst.setOpcode(ARM::VMOVv1i64);
5139         } else {
5140           Inst.setOpcode(ARM::VMOVv8i8);
5141         }
5142       }
5143       if (cmode == 0xD) {
5144         if (op == 1) {
5145           Inst.setOpcode(ARM::VMVNv2i32);
5146         } else {
5147           Inst.setOpcode(ARM::VMOVv2i32);
5148         }
5149       }
5150       if (cmode == 0xC) {
5151         if (op == 1) {
5152           Inst.setOpcode(ARM::VMVNv2i32);
5153         } else {
5154           Inst.setOpcode(ARM::VMOVv2i32);
5155         }
5156       }
5157     }
5158     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
5159   }
5160 
5161   if (!(imm & 0x20)) return MCDisassembler::Fail;
5162 
5163   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
5164     return MCDisassembler::Fail;
5165   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
5166     return MCDisassembler::Fail;
5167   Inst.addOperand(MCOperand::createImm(64 - imm));
5168 
5169   return S;
5170 }
5171 
5172 static DecodeStatus DecodeVCVTQ(MCInst &Inst, unsigned Insn,
5173                                 uint64_t Address, const void *Decoder) {
5174   const FeatureBitset &featureBits =
5175       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5176   bool hasFullFP16 = featureBits[ARM::FeatureFullFP16];
5177 
5178   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5179   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5180   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5181   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5182   unsigned imm = fieldFromInstruction(Insn, 16, 6);
5183   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
5184   unsigned op = fieldFromInstruction(Insn, 5, 1);
5185 
5186   DecodeStatus S = MCDisassembler::Success;
5187 
5188   // If the top 3 bits of imm are clear, this is a VMOV (immediate)
5189   if (!(imm & 0x38)) {
5190     if (cmode == 0xF) {
5191       if (op == 1) return MCDisassembler::Fail;
5192       Inst.setOpcode(ARM::VMOVv4f32);
5193     }
5194     if (hasFullFP16) {
5195       if (cmode == 0xE) {
5196         if (op == 1) {
5197           Inst.setOpcode(ARM::VMOVv2i64);
5198         } else {
5199           Inst.setOpcode(ARM::VMOVv16i8);
5200         }
5201       }
5202       if (cmode == 0xD) {
5203         if (op == 1) {
5204           Inst.setOpcode(ARM::VMVNv4i32);
5205         } else {
5206           Inst.setOpcode(ARM::VMOVv4i32);
5207         }
5208       }
5209       if (cmode == 0xC) {
5210         if (op == 1) {
5211           Inst.setOpcode(ARM::VMVNv4i32);
5212         } else {
5213           Inst.setOpcode(ARM::VMOVv4i32);
5214         }
5215       }
5216     }
5217     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
5218   }
5219 
5220   if (!(imm & 0x20)) return MCDisassembler::Fail;
5221 
5222   if (!Check(S, DecodeQPRRegisterClass(Inst, Vd, Address, Decoder)))
5223     return MCDisassembler::Fail;
5224   if (!Check(S, DecodeQPRRegisterClass(Inst, Vm, Address, Decoder)))
5225     return MCDisassembler::Fail;
5226   Inst.addOperand(MCOperand::createImm(64 - imm));
5227 
5228   return S;
5229 }
5230 
5231 static DecodeStatus DecodeNEONComplexLane64Instruction(MCInst &Inst,
5232                                                        unsigned Insn,
5233                                                        uint64_t Address,
5234                                                        const void *Decoder) {
5235   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5236   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5237   unsigned Vn = (fieldFromInstruction(Insn, 16, 4) << 0);
5238   Vn |= (fieldFromInstruction(Insn, 7, 1) << 4);
5239   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5240   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5241   unsigned q = (fieldFromInstruction(Insn, 6, 1) << 0);
5242   unsigned rotate = (fieldFromInstruction(Insn, 20, 2) << 0);
5243 
5244   DecodeStatus S = MCDisassembler::Success;
5245 
5246   auto DestRegDecoder = q ? DecodeQPRRegisterClass : DecodeDPRRegisterClass;
5247 
5248   if (!Check(S, DestRegDecoder(Inst, Vd, Address, Decoder)))
5249     return MCDisassembler::Fail;
5250   if (!Check(S, DestRegDecoder(Inst, Vd, Address, Decoder)))
5251     return MCDisassembler::Fail;
5252   if (!Check(S, DestRegDecoder(Inst, Vn, Address, Decoder)))
5253     return MCDisassembler::Fail;
5254   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
5255     return MCDisassembler::Fail;
5256   // The lane index does not have any bits in the encoding, because it can only
5257   // be 0.
5258   Inst.addOperand(MCOperand::createImm(0));
5259   Inst.addOperand(MCOperand::createImm(rotate));
5260 
5261   return S;
5262 }
5263 
5264 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
5265                                 uint64_t Address, const void *Decoder) {
5266   DecodeStatus S = MCDisassembler::Success;
5267 
5268   unsigned Rn = fieldFromInstruction(Val, 16, 4);
5269   unsigned Rt = fieldFromInstruction(Val, 12, 4);
5270   unsigned Rm = fieldFromInstruction(Val, 0, 4);
5271   Rm |= (fieldFromInstruction(Val, 23, 1) << 4);
5272   unsigned Cond = fieldFromInstruction(Val, 28, 4);
5273 
5274   if (fieldFromInstruction(Val, 8, 4) != 0 || Rn == Rt)
5275     S = MCDisassembler::SoftFail;
5276 
5277   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5278     return MCDisassembler::Fail;
5279   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
5280     return MCDisassembler::Fail;
5281   if (!Check(S, DecodeAddrMode7Operand(Inst, Rn, Address, Decoder)))
5282     return MCDisassembler::Fail;
5283   if (!Check(S, DecodePostIdxReg(Inst, Rm, Address, Decoder)))
5284     return MCDisassembler::Fail;
5285   if (!Check(S, DecodePredicateOperand(Inst, Cond, Address, Decoder)))
5286     return MCDisassembler::Fail;
5287 
5288   return S;
5289 }
5290 
5291 static DecodeStatus DecoderForMRRC2AndMCRR2(MCInst &Inst, unsigned Val,
5292                                             uint64_t Address, const void *Decoder) {
5293   DecodeStatus S = MCDisassembler::Success;
5294 
5295   unsigned CRm = fieldFromInstruction(Val, 0, 4);
5296   unsigned opc1 = fieldFromInstruction(Val, 4, 4);
5297   unsigned cop = fieldFromInstruction(Val, 8, 4);
5298   unsigned Rt = fieldFromInstruction(Val, 12, 4);
5299   unsigned Rt2 = fieldFromInstruction(Val, 16, 4);
5300 
5301   if ((cop & ~0x1) == 0xa)
5302     return MCDisassembler::Fail;
5303 
5304   if (Rt == Rt2)
5305     S = MCDisassembler::SoftFail;
5306 
5307   // We have to check if the instruction is MRRC2
5308   // or MCRR2 when constructing the operands for
5309   // Inst. Reason is because MRRC2 stores to two
5310   // registers so it's tablegen desc has has two
5311   // outputs whereas MCRR doesn't store to any
5312   // registers so all of it's operands are listed
5313   // as inputs, therefore the operand order for
5314   // MRRC2 needs to be [Rt, Rt2, cop, opc1, CRm]
5315   // and MCRR2 operand order is [cop, opc1, Rt, Rt2, CRm]
5316 
5317   if (Inst.getOpcode() == ARM::MRRC2) {
5318     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5319       return MCDisassembler::Fail;
5320     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5321       return MCDisassembler::Fail;
5322   }
5323   Inst.addOperand(MCOperand::createImm(cop));
5324   Inst.addOperand(MCOperand::createImm(opc1));
5325   if (Inst.getOpcode() == ARM::MCRR2) {
5326     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5327       return MCDisassembler::Fail;
5328     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5329       return MCDisassembler::Fail;
5330   }
5331   Inst.addOperand(MCOperand::createImm(CRm));
5332 
5333   return S;
5334 }
5335 
5336 static DecodeStatus DecodeForVMRSandVMSR(MCInst &Inst, unsigned Val,
5337                                          uint64_t Address,
5338                                          const void *Decoder) {
5339   const FeatureBitset &featureBits =
5340       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5341   DecodeStatus S = MCDisassembler::Success;
5342 
5343   unsigned Rt = fieldFromInstruction(Val, 12, 4);
5344 
5345   if (featureBits[ARM::ModeThumb] && !featureBits[ARM::HasV8Ops]) {
5346     if (Rt == 13 || Rt == 15)
5347       S = MCDisassembler::SoftFail;
5348     Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
5349   } else
5350     Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder));
5351 
5352   if (featureBits[ARM::ModeThumb]) {
5353     Inst.addOperand(MCOperand::createImm(ARMCC::AL));
5354     Inst.addOperand(MCOperand::createReg(0));
5355   } else {
5356     unsigned pred = fieldFromInstruction(Val, 28, 4);
5357     if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5358       return MCDisassembler::Fail;
5359   }
5360 
5361   return S;
5362 }
5363