xref: /llvm-project/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (revision c20c37ba7f546e0898e09953f03ca2c28ddc7035)
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(DecodeStatus &, 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 DecodeSPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
169                                    uint64_t Address, const void *Decoder);
170 static DecodeStatus DecodeDPR_VFP2RegisterClass(MCInst &Inst,
171                                                 unsigned RegNo,
172                                                 uint64_t Address,
173                                                 const void *Decoder);
174 static DecodeStatus DecodeQPRRegisterClass(MCInst &Inst, unsigned RegNo,
175                                    uint64_t Address, const void *Decoder);
176 static DecodeStatus DecodeDPairRegisterClass(MCInst &Inst, unsigned RegNo,
177                                    uint64_t Address, const void *Decoder);
178 static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst &Inst,
179                                unsigned RegNo, uint64_t Address,
180                                const void *Decoder);
181 
182 static DecodeStatus DecodePredicateOperand(MCInst &Inst, unsigned Val,
183                                uint64_t Address, const void *Decoder);
184 static DecodeStatus DecodeCCOutOperand(MCInst &Inst, unsigned Val,
185                                uint64_t Address, const void *Decoder);
186 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
187                                uint64_t Address, const void *Decoder);
188 static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
189                                uint64_t Address, const void *Decoder);
190 static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
191                                uint64_t Address, const void *Decoder);
192 
193 static DecodeStatus DecodeBitfieldMaskOperand(MCInst &Inst, unsigned Insn,
194                                uint64_t Address, const void *Decoder);
195 static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
196                                uint64_t Address, const void *Decoder);
197 static DecodeStatus DecodeAddrMode2IdxInstruction(MCInst &Inst,
198                                                   unsigned Insn,
199                                                   uint64_t Address,
200                                                   const void *Decoder);
201 static DecodeStatus DecodeSORegMemOperand(MCInst &Inst, unsigned Insn,
202                                uint64_t Address, const void *Decoder);
203 static DecodeStatus DecodeAddrMode3Instruction(MCInst &Inst,unsigned Insn,
204                                uint64_t Address, const void *Decoder);
205 static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Insn,
206                                uint64_t Address, const void *Decoder);
207 static DecodeStatus DecodeSORegRegOperand(MCInst &Inst, unsigned Insn,
208                                uint64_t Address, const void *Decoder);
209 
210 static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst & Inst,
211                                                   unsigned Insn,
212                                                   uint64_t Adddress,
213                                                   const void *Decoder);
214 static DecodeStatus DecodeT2MOVTWInstruction(MCInst &Inst, unsigned Insn,
215                                uint64_t Address, const void *Decoder);
216 static DecodeStatus DecodeArmMOVTWInstruction(MCInst &Inst, unsigned Insn,
217                                uint64_t Address, const void *Decoder);
218 static DecodeStatus DecodeSMLAInstruction(MCInst &Inst, unsigned Insn,
219                                uint64_t Address, const void *Decoder);
220 static DecodeStatus DecodeHINTInstruction(MCInst &Inst, unsigned Insn,
221                                uint64_t Address, const void *Decoder);
222 static DecodeStatus DecodeCPSInstruction(MCInst &Inst, unsigned Insn,
223                                uint64_t Address, const void *Decoder);
224 static DecodeStatus DecodeTSTInstruction(MCInst &Inst, unsigned Insn,
225                                uint64_t Address, const void *Decoder);
226 static DecodeStatus DecodeSETPANInstruction(MCInst &Inst, unsigned Insn,
227                                uint64_t Address, const void *Decoder);
228 static DecodeStatus DecodeT2CPSInstruction(MCInst &Inst, unsigned Insn,
229                                uint64_t Address, const void *Decoder);
230 static DecodeStatus DecodeAddrModeImm12Operand(MCInst &Inst, unsigned Val,
231                                uint64_t Address, const void *Decoder);
232 static DecodeStatus DecodeAddrMode5Operand(MCInst &Inst, unsigned Val,
233                                uint64_t Address, const void *Decoder);
234 static DecodeStatus DecodeAddrMode5FP16Operand(MCInst &Inst, unsigned Val,
235                                uint64_t Address, const void *Decoder);
236 static DecodeStatus DecodeAddrMode7Operand(MCInst &Inst, unsigned Val,
237                                uint64_t Address, const void *Decoder);
238 static DecodeStatus DecodeT2BInstruction(MCInst &Inst, unsigned Insn,
239                                uint64_t Address, const void *Decoder);
240 static DecodeStatus DecodeBranchImmInstruction(MCInst &Inst,unsigned Insn,
241                                uint64_t Address, const void *Decoder);
242 static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
243                                uint64_t Address, const void *Decoder);
244 static DecodeStatus DecodeVLDST1Instruction(MCInst &Inst, unsigned Val,
245                                uint64_t Address, const void *Decoder);
246 static DecodeStatus DecodeVLDST2Instruction(MCInst &Inst, unsigned Val,
247                                uint64_t Address, const void *Decoder);
248 static DecodeStatus DecodeVLDST3Instruction(MCInst &Inst, unsigned Val,
249                                uint64_t Address, const void *Decoder);
250 static DecodeStatus DecodeVLDST4Instruction(MCInst &Inst, unsigned Val,
251                                uint64_t Address, const void *Decoder);
252 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Val,
253                                uint64_t Address, const void *Decoder);
254 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Val,
255                                uint64_t Address, const void *Decoder);
256 static DecodeStatus DecodeVLD1DupInstruction(MCInst &Inst, unsigned Val,
257                                uint64_t Address, const void *Decoder);
258 static DecodeStatus DecodeVLD2DupInstruction(MCInst &Inst, unsigned Val,
259                                uint64_t Address, const void *Decoder);
260 static DecodeStatus DecodeVLD3DupInstruction(MCInst &Inst, unsigned Val,
261                                uint64_t Address, const void *Decoder);
262 static DecodeStatus DecodeVLD4DupInstruction(MCInst &Inst, unsigned Val,
263                                uint64_t Address, const void *Decoder);
264 static DecodeStatus DecodeNEONModImmInstruction(MCInst &Inst,unsigned Val,
265                                uint64_t Address, const void *Decoder);
266 static DecodeStatus DecodeVSHLMaxInstruction(MCInst &Inst, unsigned Val,
267                                uint64_t Address, const void *Decoder);
268 static DecodeStatus DecodeShiftRight8Imm(MCInst &Inst, unsigned Val,
269                                uint64_t Address, const void *Decoder);
270 static DecodeStatus DecodeShiftRight16Imm(MCInst &Inst, unsigned Val,
271                                uint64_t Address, const void *Decoder);
272 static DecodeStatus DecodeShiftRight32Imm(MCInst &Inst, unsigned Val,
273                                uint64_t Address, const void *Decoder);
274 static DecodeStatus DecodeShiftRight64Imm(MCInst &Inst, unsigned Val,
275                                uint64_t Address, const void *Decoder);
276 static DecodeStatus DecodeTBLInstruction(MCInst &Inst, unsigned Insn,
277                                uint64_t Address, const void *Decoder);
278 static DecodeStatus DecodePostIdxReg(MCInst &Inst, unsigned Insn,
279                                uint64_t Address, const void *Decoder);
280 static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Insn,
281                                uint64_t Address, const void *Decoder);
282 static DecodeStatus DecodeMemBarrierOption(MCInst &Inst, unsigned Insn,
283                                uint64_t Address, const void *Decoder);
284 static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Insn,
285                                uint64_t Address, const void *Decoder);
286 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Insn,
287                                uint64_t Address, const void *Decoder);
288 static DecodeStatus DecodeBankedReg(MCInst &Inst, unsigned Insn,
289                                uint64_t Address, const void *Decoder);
290 static DecodeStatus DecodeDoubleRegLoad(MCInst &Inst, unsigned Insn,
291                                uint64_t Address, const void *Decoder);
292 static DecodeStatus DecodeDoubleRegStore(MCInst &Inst, unsigned Insn,
293                                uint64_t Address, const void *Decoder);
294 static DecodeStatus DecodeLDRPreImm(MCInst &Inst, unsigned Insn,
295                                uint64_t Address, const void *Decoder);
296 static DecodeStatus DecodeLDRPreReg(MCInst &Inst, unsigned Insn,
297                                uint64_t Address, const void *Decoder);
298 static DecodeStatus DecodeSTRPreImm(MCInst &Inst, unsigned Insn,
299                                uint64_t Address, const void *Decoder);
300 static DecodeStatus DecodeSTRPreReg(MCInst &Inst, unsigned Insn,
301                                uint64_t Address, const void *Decoder);
302 static DecodeStatus DecodeVLD1LN(MCInst &Inst, unsigned Insn,
303                                uint64_t Address, const void *Decoder);
304 static DecodeStatus DecodeVLD2LN(MCInst &Inst, unsigned Insn,
305                                uint64_t Address, const void *Decoder);
306 static DecodeStatus DecodeVLD3LN(MCInst &Inst, unsigned Insn,
307                                uint64_t Address, const void *Decoder);
308 static DecodeStatus DecodeVLD4LN(MCInst &Inst, unsigned Insn,
309                                uint64_t Address, const void *Decoder);
310 static DecodeStatus DecodeVST1LN(MCInst &Inst, unsigned Insn,
311                                uint64_t Address, const void *Decoder);
312 static DecodeStatus DecodeVST2LN(MCInst &Inst, unsigned Insn,
313                                uint64_t Address, const void *Decoder);
314 static DecodeStatus DecodeVST3LN(MCInst &Inst, unsigned Insn,
315                                uint64_t Address, const void *Decoder);
316 static DecodeStatus DecodeVST4LN(MCInst &Inst, unsigned Insn,
317                                uint64_t Address, const void *Decoder);
318 static DecodeStatus DecodeVMOVSRR(MCInst &Inst, unsigned Insn,
319                                uint64_t Address, const void *Decoder);
320 static DecodeStatus DecodeVMOVRRS(MCInst &Inst, unsigned Insn,
321                                uint64_t Address, const void *Decoder);
322 static DecodeStatus DecodeSwap(MCInst &Inst, unsigned Insn,
323                                uint64_t Address, const void *Decoder);
324 static DecodeStatus DecodeVCVTD(MCInst &Inst, unsigned Insn,
325                                 uint64_t Address, const void *Decoder);
326 static DecodeStatus DecodeVCVTQ(MCInst &Inst, unsigned Insn,
327                                 uint64_t Address, const void *Decoder);
328 static DecodeStatus DecodeNEONComplexLane64Instruction(MCInst &Inst,
329                                                        unsigned Val,
330                                                        uint64_t Address,
331                                                        const void *Decoder);
332 
333 static DecodeStatus DecodeThumbAddSpecialReg(MCInst &Inst, uint16_t Insn,
334                                uint64_t Address, const void *Decoder);
335 static DecodeStatus DecodeThumbBROperand(MCInst &Inst, unsigned Val,
336                                uint64_t Address, const void *Decoder);
337 static DecodeStatus DecodeT2BROperand(MCInst &Inst, unsigned Val,
338                                uint64_t Address, const void *Decoder);
339 static DecodeStatus DecodeThumbCmpBROperand(MCInst &Inst, unsigned Val,
340                                uint64_t Address, const void *Decoder);
341 static DecodeStatus DecodeThumbAddrModeRR(MCInst &Inst, unsigned Val,
342                                uint64_t Address, const void *Decoder);
343 static DecodeStatus DecodeThumbAddrModeIS(MCInst &Inst, unsigned Val,
344                                uint64_t Address, const void *Decoder);
345 static DecodeStatus DecodeThumbAddrModePC(MCInst &Inst, unsigned Val,
346                                uint64_t Address, const void *Decoder);
347 static DecodeStatus DecodeThumbAddrModeSP(MCInst &Inst, unsigned Val,
348                                uint64_t Address, const void *Decoder);
349 static DecodeStatus DecodeT2AddrModeSOReg(MCInst &Inst, unsigned Val,
350                                uint64_t Address, const void *Decoder);
351 static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Val,
352                                uint64_t Address, const void *Decoder);
353 static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
354                                uint64_t Address, const void* Decoder);
355 static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
356                                uint64_t Address, const void* Decoder);
357 static DecodeStatus DecodeT2LoadT(MCInst &Inst, unsigned Insn,
358                                uint64_t Address, const void* Decoder);
359 static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
360                                uint64_t Address, const void* Decoder);
361 static DecodeStatus DecodeT2Imm8S4(MCInst &Inst, unsigned Val,
362                                uint64_t Address, const void *Decoder);
363 static DecodeStatus DecodeT2AddrModeImm8s4(MCInst &Inst, unsigned Val,
364                                uint64_t Address, const void *Decoder);
365 static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst &Inst,unsigned Val,
366                                uint64_t Address, const void *Decoder);
367 static DecodeStatus DecodeT2Imm8(MCInst &Inst, unsigned Val,
368                                uint64_t Address, const void *Decoder);
369 static DecodeStatus DecodeT2AddrModeImm8(MCInst &Inst, unsigned Val,
370                                uint64_t Address, const void *Decoder);
371 static DecodeStatus DecodeThumbAddSPImm(MCInst &Inst, uint16_t Val,
372                                uint64_t Address, const void *Decoder);
373 static DecodeStatus DecodeThumbAddSPReg(MCInst &Inst, uint16_t Insn,
374                                 uint64_t Address, const void *Decoder);
375 static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
376                                 uint64_t Address, const void *Decoder);
377 static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
378                                 uint64_t Address, const void *Decoder);
379 static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Insn,
380                                 uint64_t Address, const void *Decoder);
381 static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
382                                 uint64_t Address, const void *Decoder);
383 static DecodeStatus DecodeThumbTableBranch(MCInst &Inst, unsigned Val,
384                                 uint64_t Address, const void *Decoder);
385 static DecodeStatus DecodeThumb2BCCInstruction(MCInst &Inst, unsigned Val,
386                                 uint64_t Address, const void *Decoder);
387 static DecodeStatus DecodeT2SOImm(MCInst &Inst, unsigned Val,
388                                 uint64_t Address, const void *Decoder);
389 static DecodeStatus DecodeThumbBCCTargetOperand(MCInst &Inst,unsigned Val,
390                                 uint64_t Address, const void *Decoder);
391 static DecodeStatus DecodeThumbBLTargetOperand(MCInst &Inst, unsigned Val,
392                                 uint64_t Address, const void *Decoder);
393 static DecodeStatus DecodeIT(MCInst &Inst, unsigned Val,
394                                 uint64_t Address, const void *Decoder);
395 static DecodeStatus DecodeT2LDRDPreInstruction(MCInst &Inst,unsigned Insn,
396                                uint64_t Address, const void *Decoder);
397 static DecodeStatus DecodeT2STRDPreInstruction(MCInst &Inst,unsigned Insn,
398                                uint64_t Address, const void *Decoder);
399 static DecodeStatus DecodeT2Adr(MCInst &Inst, unsigned Val,
400                                 uint64_t Address, const void *Decoder);
401 static DecodeStatus DecodeT2LdStPre(MCInst &Inst, unsigned Val,
402                                 uint64_t Address, const void *Decoder);
403 static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, unsigned Val,
404                                 uint64_t Address, const void *Decoder);
405 
406 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
407                                 uint64_t Address, const void *Decoder);
408 static DecodeStatus DecoderForMRRC2AndMCRR2(MCInst &Inst, unsigned Val,
409                                             uint64_t Address, const void *Decoder);
410 static DecodeStatus DecodeForVMRSandVMSR(MCInst &Inst, unsigned Val,
411                                          uint64_t Address, const void *Decoder);
412 
413 #include "ARMGenDisassemblerTables.inc"
414 
415 static MCDisassembler *createARMDisassembler(const Target &T,
416                                              const MCSubtargetInfo &STI,
417                                              MCContext &Ctx) {
418   return new ARMDisassembler(STI, Ctx);
419 }
420 
421 static MCDisassembler *createThumbDisassembler(const Target &T,
422                                                const MCSubtargetInfo &STI,
423                                                MCContext &Ctx) {
424   return new ThumbDisassembler(STI, Ctx);
425 }
426 
427 // Post-decoding checks
428 static DecodeStatus checkDecodedInstruction(MCInst &MI, uint64_t &Size,
429                                             uint64_t Address, raw_ostream &OS,
430                                             raw_ostream &CS,
431                                             uint32_t Insn,
432                                             DecodeStatus Result) {
433   switch (MI.getOpcode()) {
434     case ARM::HVC: {
435       // HVC is undefined if condition = 0xf otherwise upredictable
436       // if condition != 0xe
437       uint32_t Cond = (Insn >> 28) & 0xF;
438       if (Cond == 0xF)
439         return MCDisassembler::Fail;
440       if (Cond != 0xE)
441         return MCDisassembler::SoftFail;
442       return Result;
443     }
444     default: return Result;
445   }
446 }
447 
448 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
449                                              ArrayRef<uint8_t> Bytes,
450                                              uint64_t Address, raw_ostream &OS,
451                                              raw_ostream &CS) const {
452   CommentStream = &CS;
453 
454   assert(!STI.getFeatureBits()[ARM::ModeThumb] &&
455          "Asked to disassemble an ARM instruction but Subtarget is in Thumb "
456          "mode!");
457 
458   // We want to read exactly 4 bytes of data.
459   if (Bytes.size() < 4) {
460     Size = 0;
461     return MCDisassembler::Fail;
462   }
463 
464   // Encoded as a small-endian 32-bit word in the stream.
465   uint32_t Insn =
466       (Bytes[3] << 24) | (Bytes[2] << 16) | (Bytes[1] << 8) | (Bytes[0] << 0);
467 
468   // Calling the auto-generated decoder function.
469   DecodeStatus Result =
470       decodeInstruction(DecoderTableARM32, MI, Insn, Address, this, STI);
471   if (Result != MCDisassembler::Fail) {
472     Size = 4;
473     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
474   }
475 
476   struct DecodeTable {
477     const uint8_t *P;
478     bool DecodePred;
479   };
480 
481   const DecodeTable Tables[] = {
482       {DecoderTableVFP32, false},      {DecoderTableVFPV832, false},
483       {DecoderTableNEONData32, true},  {DecoderTableNEONLoadStore32, true},
484       {DecoderTableNEONDup32, true},   {DecoderTablev8NEON32, false},
485       {DecoderTablev8Crypto32, false},
486   };
487 
488   for (auto Table : Tables) {
489     Result = decodeInstruction(Table.P, MI, Insn, Address, this, STI);
490     if (Result != MCDisassembler::Fail) {
491       Size = 4;
492       // Add a fake predicate operand, because we share these instruction
493       // definitions with Thumb2 where these instructions are predicable.
494       if (Table.DecodePred && !DecodePredicateOperand(MI, 0xE, Address, this))
495         return MCDisassembler::Fail;
496       return Result;
497     }
498   }
499 
500   Result =
501       decodeInstruction(DecoderTableCoProc32, MI, Insn, Address, this, STI);
502   if (Result != MCDisassembler::Fail) {
503     Size = 4;
504     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
505   }
506 
507   Size = 4;
508   return MCDisassembler::Fail;
509 }
510 
511 namespace llvm {
512 
513 extern const MCInstrDesc ARMInsts[];
514 
515 } // end namespace llvm
516 
517 /// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the
518 /// immediate Value in the MCInst.  The immediate Value has had any PC
519 /// adjustment made by the caller.  If the instruction is a branch instruction
520 /// then isBranch is true, else false.  If the getOpInfo() function was set as
521 /// part of the setupForSymbolicDisassembly() call then that function is called
522 /// to get any symbolic information at the Address for this instruction.  If
523 /// that returns non-zero then the symbolic information it returns is used to
524 /// create an MCExpr and that is added as an operand to the MCInst.  If
525 /// getOpInfo() returns zero and isBranch is true then a symbol look up for
526 /// Value is done and if a symbol is found an MCExpr is created with that, else
527 /// an MCExpr with Value is created.  This function returns true if it adds an
528 /// operand to the MCInst and false otherwise.
529 static bool tryAddingSymbolicOperand(uint64_t Address, int32_t Value,
530                                      bool isBranch, uint64_t InstSize,
531                                      MCInst &MI, const void *Decoder) {
532   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
533   // FIXME: Does it make sense for value to be negative?
534   return Dis->tryAddingSymbolicOperand(MI, (uint32_t)Value, Address, isBranch,
535                                        /* Offset */ 0, InstSize);
536 }
537 
538 /// tryAddingPcLoadReferenceComment - trys to add a comment as to what is being
539 /// referenced by a load instruction with the base register that is the Pc.
540 /// These can often be values in a literal pool near the Address of the
541 /// instruction.  The Address of the instruction and its immediate Value are
542 /// used as a possible literal pool entry.  The SymbolLookUp call back will
543 /// return the name of a symbol referenced by the literal pool's entry if
544 /// the referenced address is that of a symbol.  Or it will return a pointer to
545 /// a literal 'C' string if the referenced address of the literal pool's entry
546 /// is an address into a section with 'C' string literals.
547 static void tryAddingPcLoadReferenceComment(uint64_t Address, int Value,
548                                             const void *Decoder) {
549   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
550   Dis->tryAddingPcLoadReferenceComment(Value, Address);
551 }
552 
553 // Thumb1 instructions don't have explicit S bits.  Rather, they
554 // implicitly set CPSR.  Since it's not represented in the encoding, the
555 // auto-generated decoder won't inject the CPSR operand.  We need to fix
556 // that as a post-pass.
557 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
558   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
559   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
560   MCInst::iterator I = MI.begin();
561   for (unsigned i = 0; i < NumOps; ++i, ++I) {
562     if (I == MI.end()) break;
563     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
564       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
565       MI.insert(I, MCOperand::createReg(InITBlock ? 0 : ARM::CPSR));
566       return;
567     }
568   }
569 
570   MI.insert(I, MCOperand::createReg(InITBlock ? 0 : ARM::CPSR));
571 }
572 
573 // Most Thumb instructions don't have explicit predicates in the
574 // encoding, but rather get their predicates from IT context.  We need
575 // to fix up the predicate operands using this context information as a
576 // post-pass.
577 MCDisassembler::DecodeStatus
578 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
579   MCDisassembler::DecodeStatus S = Success;
580 
581   const FeatureBitset &FeatureBits = getSubtargetInfo().getFeatureBits();
582 
583   // A few instructions actually have predicates encoded in them.  Don't
584   // try to overwrite it if we're seeing one of those.
585   switch (MI.getOpcode()) {
586     case ARM::tBcc:
587     case ARM::t2Bcc:
588     case ARM::tCBZ:
589     case ARM::tCBNZ:
590     case ARM::tCPS:
591     case ARM::t2CPS3p:
592     case ARM::t2CPS2p:
593     case ARM::t2CPS1p:
594     case ARM::tMOVSr:
595     case ARM::tSETEND:
596       // Some instructions (mostly conditional branches) are not
597       // allowed in IT blocks.
598       if (ITBlock.instrInITBlock())
599         S = SoftFail;
600       else
601         return Success;
602       break;
603     case ARM::t2HINT:
604       if (MI.getOperand(0).getImm() == 0x10 && (FeatureBits[ARM::FeatureRAS]) != 0)
605         S = SoftFail;
606       break;
607     case ARM::tB:
608     case ARM::t2B:
609     case ARM::t2TBB:
610     case ARM::t2TBH:
611       // Some instructions (mostly unconditional branches) can
612       // only appears at the end of, or outside of, an IT.
613       if (ITBlock.instrInITBlock() && !ITBlock.instrLastInITBlock())
614         S = SoftFail;
615       break;
616     default:
617       break;
618   }
619 
620   // If we're in an IT block, base the predicate on that.  Otherwise,
621   // assume a predicate of AL.
622   unsigned CC;
623   CC = ITBlock.getITCC();
624   if (CC == 0xF)
625     CC = ARMCC::AL;
626   if (ITBlock.instrInITBlock())
627     ITBlock.advanceITState();
628 
629   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
630   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
631   MCInst::iterator I = MI.begin();
632   for (unsigned i = 0; i < NumOps; ++i, ++I) {
633     if (I == MI.end()) break;
634     if (OpInfo[i].isPredicate()) {
635       if (CC != ARMCC::AL && !ARMInsts[MI.getOpcode()].isPredicable())
636         Check(S, SoftFail);
637       I = MI.insert(I, MCOperand::createImm(CC));
638       ++I;
639       if (CC == ARMCC::AL)
640         MI.insert(I, MCOperand::createReg(0));
641       else
642         MI.insert(I, MCOperand::createReg(ARM::CPSR));
643       return S;
644     }
645   }
646 
647   I = MI.insert(I, MCOperand::createImm(CC));
648   ++I;
649   if (CC == ARMCC::AL)
650     MI.insert(I, MCOperand::createReg(0));
651   else
652     MI.insert(I, MCOperand::createReg(ARM::CPSR));
653 
654   return S;
655 }
656 
657 // Thumb VFP instructions are a special case.  Because we share their
658 // encodings between ARM and Thumb modes, and they are predicable in ARM
659 // mode, the auto-generated decoder will give them an (incorrect)
660 // predicate operand.  We need to rewrite these operands based on the IT
661 // context as a post-pass.
662 void ThumbDisassembler::UpdateThumbVFPPredicate(
663   DecodeStatus &S, MCInst &MI) const {
664   unsigned CC;
665   CC = ITBlock.getITCC();
666   if (CC == 0xF)
667     CC = ARMCC::AL;
668   if (ITBlock.instrInITBlock())
669     ITBlock.advanceITState();
670 
671   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
672   MCInst::iterator I = MI.begin();
673   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
674   for (unsigned i = 0; i < NumOps; ++i, ++I) {
675     if (OpInfo[i].isPredicate() ) {
676       if (CC != ARMCC::AL && !ARMInsts[MI.getOpcode()].isPredicable())
677         Check(S, SoftFail);
678       I->setImm(CC);
679       ++I;
680       if (CC == ARMCC::AL)
681         I->setReg(0);
682       else
683         I->setReg(ARM::CPSR);
684       return;
685     }
686   }
687 }
688 
689 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
690                                                ArrayRef<uint8_t> Bytes,
691                                                uint64_t Address,
692                                                raw_ostream &OS,
693                                                raw_ostream &CS) const {
694   CommentStream = &CS;
695 
696   assert(STI.getFeatureBits()[ARM::ModeThumb] &&
697          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
698 
699   // We want to read exactly 2 bytes of data.
700   if (Bytes.size() < 2) {
701     Size = 0;
702     return MCDisassembler::Fail;
703   }
704 
705   uint16_t Insn16 = (Bytes[1] << 8) | Bytes[0];
706   DecodeStatus Result =
707       decodeInstruction(DecoderTableThumb16, MI, Insn16, Address, this, STI);
708   if (Result != MCDisassembler::Fail) {
709     Size = 2;
710     Check(Result, AddThumbPredicate(MI));
711     return Result;
712   }
713 
714   Result = decodeInstruction(DecoderTableThumbSBit16, MI, Insn16, Address, this,
715                              STI);
716   if (Result) {
717     Size = 2;
718     bool InITBlock = ITBlock.instrInITBlock();
719     Check(Result, AddThumbPredicate(MI));
720     AddThumb1SBit(MI, InITBlock);
721     return Result;
722   }
723 
724   Result =
725       decodeInstruction(DecoderTableThumb216, MI, Insn16, Address, this, STI);
726   if (Result != MCDisassembler::Fail) {
727     Size = 2;
728 
729     // Nested IT blocks are UNPREDICTABLE.  Must be checked before we add
730     // the Thumb predicate.
731     if (MI.getOpcode() == ARM::t2IT && ITBlock.instrInITBlock())
732       Result = MCDisassembler::SoftFail;
733 
734     Check(Result, AddThumbPredicate(MI));
735 
736     // If we find an IT instruction, we need to parse its condition
737     // code and mask operands so that we can apply them correctly
738     // to the subsequent instructions.
739     if (MI.getOpcode() == ARM::t2IT) {
740       unsigned Firstcond = MI.getOperand(0).getImm();
741       unsigned Mask = MI.getOperand(1).getImm();
742       ITBlock.setITState(Firstcond, Mask);
743 
744       // An IT instruction that would give a 'NV' predicate is unpredictable.
745       if (Firstcond == ARMCC::AL && !isPowerOf2_32(Mask))
746         CS << "unpredictable IT predicate sequence";
747     }
748 
749     return Result;
750   }
751 
752   // We want to read exactly 4 bytes of data.
753   if (Bytes.size() < 4) {
754     Size = 0;
755     return MCDisassembler::Fail;
756   }
757 
758   uint32_t Insn32 =
759       (Bytes[3] << 8) | (Bytes[2] << 0) | (Bytes[1] << 24) | (Bytes[0] << 16);
760   Result =
761       decodeInstruction(DecoderTableThumb32, MI, Insn32, Address, this, STI);
762   if (Result != MCDisassembler::Fail) {
763     Size = 4;
764     bool InITBlock = ITBlock.instrInITBlock();
765     Check(Result, AddThumbPredicate(MI));
766     AddThumb1SBit(MI, InITBlock);
767     return Result;
768   }
769 
770   Result =
771       decodeInstruction(DecoderTableThumb232, MI, Insn32, Address, this, STI);
772   if (Result != MCDisassembler::Fail) {
773     Size = 4;
774     Check(Result, AddThumbPredicate(MI));
775     return Result;
776   }
777 
778   if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
779     Result =
780         decodeInstruction(DecoderTableVFP32, MI, Insn32, Address, this, STI);
781     if (Result != MCDisassembler::Fail) {
782       Size = 4;
783       UpdateThumbVFPPredicate(Result, MI);
784       return Result;
785     }
786   }
787 
788   Result =
789       decodeInstruction(DecoderTableVFPV832, MI, Insn32, Address, this, STI);
790   if (Result != MCDisassembler::Fail) {
791     Size = 4;
792     return Result;
793   }
794 
795   if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
796     Result = decodeInstruction(DecoderTableNEONDup32, MI, Insn32, Address, this,
797                                STI);
798     if (Result != MCDisassembler::Fail) {
799       Size = 4;
800       Check(Result, AddThumbPredicate(MI));
801       return Result;
802     }
803   }
804 
805   if (fieldFromInstruction(Insn32, 24, 8) == 0xF9) {
806     uint32_t NEONLdStInsn = Insn32;
807     NEONLdStInsn &= 0xF0FFFFFF;
808     NEONLdStInsn |= 0x04000000;
809     Result = decodeInstruction(DecoderTableNEONLoadStore32, MI, NEONLdStInsn,
810                                Address, this, STI);
811     if (Result != MCDisassembler::Fail) {
812       Size = 4;
813       Check(Result, AddThumbPredicate(MI));
814       return Result;
815     }
816   }
817 
818   if (fieldFromInstruction(Insn32, 24, 4) == 0xF) {
819     uint32_t NEONDataInsn = Insn32;
820     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
821     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
822     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
823     Result = decodeInstruction(DecoderTableNEONData32, MI, NEONDataInsn,
824                                Address, this, STI);
825     if (Result != MCDisassembler::Fail) {
826       Size = 4;
827       Check(Result, AddThumbPredicate(MI));
828       return Result;
829     }
830 
831     uint32_t NEONCryptoInsn = Insn32;
832     NEONCryptoInsn &= 0xF0FFFFFF; // Clear bits 27-24
833     NEONCryptoInsn |= (NEONCryptoInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
834     NEONCryptoInsn |= 0x12000000; // Set bits 28 and 25
835     Result = decodeInstruction(DecoderTablev8Crypto32, MI, NEONCryptoInsn,
836                                Address, this, STI);
837     if (Result != MCDisassembler::Fail) {
838       Size = 4;
839       return Result;
840     }
841 
842     uint32_t NEONv8Insn = Insn32;
843     NEONv8Insn &= 0xF3FFFFFF; // Clear bits 27-26
844     Result = decodeInstruction(DecoderTablev8NEON32, MI, NEONv8Insn, Address,
845                                this, STI);
846     if (Result != MCDisassembler::Fail) {
847       Size = 4;
848       return Result;
849     }
850   }
851 
852   Result =
853       decodeInstruction(DecoderTableThumb2CoProc32, MI, Insn32, Address, this, STI);
854   if (Result != MCDisassembler::Fail) {
855     Size = 4;
856     Check(Result, AddThumbPredicate(MI));
857     return Result;
858   }
859 
860   Size = 0;
861   return MCDisassembler::Fail;
862 }
863 
864 extern "C" void LLVMInitializeARMDisassembler() {
865   TargetRegistry::RegisterMCDisassembler(getTheARMLETarget(),
866                                          createARMDisassembler);
867   TargetRegistry::RegisterMCDisassembler(getTheARMBETarget(),
868                                          createARMDisassembler);
869   TargetRegistry::RegisterMCDisassembler(getTheThumbLETarget(),
870                                          createThumbDisassembler);
871   TargetRegistry::RegisterMCDisassembler(getTheThumbBETarget(),
872                                          createThumbDisassembler);
873 }
874 
875 static const uint16_t GPRDecoderTable[] = {
876   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
877   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
878   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
879   ARM::R12, ARM::SP, ARM::LR, ARM::PC
880 };
881 
882 static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
883                                    uint64_t Address, const void *Decoder) {
884   if (RegNo > 15)
885     return MCDisassembler::Fail;
886 
887   unsigned Register = GPRDecoderTable[RegNo];
888   Inst.addOperand(MCOperand::createReg(Register));
889   return MCDisassembler::Success;
890 }
891 
892 static DecodeStatus
893 DecodeGPRnopcRegisterClass(MCInst &Inst, unsigned RegNo,
894                            uint64_t Address, const void *Decoder) {
895   DecodeStatus S = MCDisassembler::Success;
896 
897   if (RegNo == 15)
898     S = MCDisassembler::SoftFail;
899 
900   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
901 
902   return S;
903 }
904 
905 static DecodeStatus
906 DecodeGPRwithAPSRRegisterClass(MCInst &Inst, unsigned RegNo,
907                                uint64_t Address, const void *Decoder) {
908   DecodeStatus S = MCDisassembler::Success;
909 
910   if (RegNo == 15)
911   {
912     Inst.addOperand(MCOperand::createReg(ARM::APSR_NZCV));
913     return MCDisassembler::Success;
914   }
915 
916   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
917   return S;
918 }
919 
920 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
921                                    uint64_t Address, const void *Decoder) {
922   if (RegNo > 7)
923     return MCDisassembler::Fail;
924   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
925 }
926 
927 static const uint16_t GPRPairDecoderTable[] = {
928   ARM::R0_R1, ARM::R2_R3,   ARM::R4_R5,  ARM::R6_R7,
929   ARM::R8_R9, ARM::R10_R11, ARM::R12_SP
930 };
931 
932 static DecodeStatus DecodeGPRPairRegisterClass(MCInst &Inst, unsigned RegNo,
933                                    uint64_t Address, const void *Decoder) {
934   DecodeStatus S = MCDisassembler::Success;
935 
936   if (RegNo > 13)
937     return MCDisassembler::Fail;
938 
939   if ((RegNo & 1) || RegNo == 0xe)
940      S = MCDisassembler::SoftFail;
941 
942   unsigned RegisterPair = GPRPairDecoderTable[RegNo/2];
943   Inst.addOperand(MCOperand::createReg(RegisterPair));
944   return S;
945 }
946 
947 static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
948                                    uint64_t Address, const void *Decoder) {
949   unsigned Register = 0;
950   switch (RegNo) {
951     case 0:
952       Register = ARM::R0;
953       break;
954     case 1:
955       Register = ARM::R1;
956       break;
957     case 2:
958       Register = ARM::R2;
959       break;
960     case 3:
961       Register = ARM::R3;
962       break;
963     case 9:
964       Register = ARM::R9;
965       break;
966     case 12:
967       Register = ARM::R12;
968       break;
969     default:
970       return MCDisassembler::Fail;
971     }
972 
973   Inst.addOperand(MCOperand::createReg(Register));
974   return MCDisassembler::Success;
975 }
976 
977 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
978                                    uint64_t Address, const void *Decoder) {
979   DecodeStatus S = MCDisassembler::Success;
980 
981   const FeatureBitset &featureBits =
982     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
983 
984   if ((RegNo == 13 && !featureBits[ARM::HasV8Ops]) || RegNo == 15)
985     S = MCDisassembler::SoftFail;
986 
987   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
988   return S;
989 }
990 
991 static const uint16_t SPRDecoderTable[] = {
992      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
993      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
994      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
995     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
996     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
997     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
998     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
999     ARM::S28, ARM::S29, ARM::S30, ARM::S31
1000 };
1001 
1002 static DecodeStatus DecodeSPRRegisterClass(MCInst &Inst, unsigned RegNo,
1003                                    uint64_t Address, const void *Decoder) {
1004   if (RegNo > 31)
1005     return MCDisassembler::Fail;
1006 
1007   unsigned Register = SPRDecoderTable[RegNo];
1008   Inst.addOperand(MCOperand::createReg(Register));
1009   return MCDisassembler::Success;
1010 }
1011 
1012 static DecodeStatus DecodeHPRRegisterClass(MCInst &Inst, unsigned RegNo,
1013                                    uint64_t Address, const void *Decoder) {
1014   return DecodeSPRRegisterClass(Inst, RegNo, Address, Decoder);
1015 }
1016 
1017 static const uint16_t DPRDecoderTable[] = {
1018      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
1019      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
1020      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
1021     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
1022     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
1023     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
1024     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
1025     ARM::D28, ARM::D29, ARM::D30, ARM::D31
1026 };
1027 
1028 static DecodeStatus DecodeDPRRegisterClass(MCInst &Inst, unsigned RegNo,
1029                                    uint64_t Address, const void *Decoder) {
1030   const FeatureBitset &featureBits =
1031     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
1032 
1033   bool hasD16 = featureBits[ARM::FeatureD16];
1034 
1035   if (RegNo > 31 || (hasD16 && RegNo > 15))
1036     return MCDisassembler::Fail;
1037 
1038   unsigned Register = DPRDecoderTable[RegNo];
1039   Inst.addOperand(MCOperand::createReg(Register));
1040   return MCDisassembler::Success;
1041 }
1042 
1043 static DecodeStatus DecodeDPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
1044                                    uint64_t Address, const void *Decoder) {
1045   if (RegNo > 7)
1046     return MCDisassembler::Fail;
1047   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
1048 }
1049 
1050 static DecodeStatus DecodeSPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
1051                                    uint64_t Address, const void *Decoder) {
1052   if (RegNo > 15)
1053     return MCDisassembler::Fail;
1054   return DecodeSPRRegisterClass(Inst, RegNo, Address, Decoder);
1055 }
1056 
1057 static DecodeStatus
1058 DecodeDPR_VFP2RegisterClass(MCInst &Inst, unsigned RegNo,
1059                             uint64_t Address, const void *Decoder) {
1060   if (RegNo > 15)
1061     return MCDisassembler::Fail;
1062   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
1063 }
1064 
1065 static const uint16_t QPRDecoderTable[] = {
1066      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
1067      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
1068      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
1069     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
1070 };
1071 
1072 static DecodeStatus DecodeQPRRegisterClass(MCInst &Inst, unsigned RegNo,
1073                                    uint64_t Address, const void *Decoder) {
1074   if (RegNo > 31 || (RegNo & 1) != 0)
1075     return MCDisassembler::Fail;
1076   RegNo >>= 1;
1077 
1078   unsigned Register = QPRDecoderTable[RegNo];
1079   Inst.addOperand(MCOperand::createReg(Register));
1080   return MCDisassembler::Success;
1081 }
1082 
1083 static const uint16_t DPairDecoderTable[] = {
1084   ARM::Q0,  ARM::D1_D2,   ARM::Q1,  ARM::D3_D4,   ARM::Q2,  ARM::D5_D6,
1085   ARM::Q3,  ARM::D7_D8,   ARM::Q4,  ARM::D9_D10,  ARM::Q5,  ARM::D11_D12,
1086   ARM::Q6,  ARM::D13_D14, ARM::Q7,  ARM::D15_D16, ARM::Q8,  ARM::D17_D18,
1087   ARM::Q9,  ARM::D19_D20, ARM::Q10, ARM::D21_D22, ARM::Q11, ARM::D23_D24,
1088   ARM::Q12, ARM::D25_D26, ARM::Q13, ARM::D27_D28, ARM::Q14, ARM::D29_D30,
1089   ARM::Q15
1090 };
1091 
1092 static DecodeStatus DecodeDPairRegisterClass(MCInst &Inst, unsigned RegNo,
1093                                    uint64_t Address, const void *Decoder) {
1094   if (RegNo > 30)
1095     return MCDisassembler::Fail;
1096 
1097   unsigned Register = DPairDecoderTable[RegNo];
1098   Inst.addOperand(MCOperand::createReg(Register));
1099   return MCDisassembler::Success;
1100 }
1101 
1102 static const uint16_t DPairSpacedDecoderTable[] = {
1103   ARM::D0_D2,   ARM::D1_D3,   ARM::D2_D4,   ARM::D3_D5,
1104   ARM::D4_D6,   ARM::D5_D7,   ARM::D6_D8,   ARM::D7_D9,
1105   ARM::D8_D10,  ARM::D9_D11,  ARM::D10_D12, ARM::D11_D13,
1106   ARM::D12_D14, ARM::D13_D15, ARM::D14_D16, ARM::D15_D17,
1107   ARM::D16_D18, ARM::D17_D19, ARM::D18_D20, ARM::D19_D21,
1108   ARM::D20_D22, ARM::D21_D23, ARM::D22_D24, ARM::D23_D25,
1109   ARM::D24_D26, ARM::D25_D27, ARM::D26_D28, ARM::D27_D29,
1110   ARM::D28_D30, ARM::D29_D31
1111 };
1112 
1113 static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst &Inst,
1114                                                    unsigned RegNo,
1115                                                    uint64_t Address,
1116                                                    const void *Decoder) {
1117   if (RegNo > 29)
1118     return MCDisassembler::Fail;
1119 
1120   unsigned Register = DPairSpacedDecoderTable[RegNo];
1121   Inst.addOperand(MCOperand::createReg(Register));
1122   return MCDisassembler::Success;
1123 }
1124 
1125 static DecodeStatus DecodePredicateOperand(MCInst &Inst, unsigned Val,
1126                                uint64_t Address, const void *Decoder) {
1127   DecodeStatus S = MCDisassembler::Success;
1128   if (Val == 0xF) return MCDisassembler::Fail;
1129   // AL predicate is not allowed on Thumb1 branches.
1130   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
1131     return MCDisassembler::Fail;
1132   if (Val != ARMCC::AL && !ARMInsts[Inst.getOpcode()].isPredicable())
1133     Check(S, MCDisassembler::SoftFail);
1134   Inst.addOperand(MCOperand::createImm(Val));
1135   if (Val == ARMCC::AL) {
1136     Inst.addOperand(MCOperand::createReg(0));
1137   } else
1138     Inst.addOperand(MCOperand::createReg(ARM::CPSR));
1139   return S;
1140 }
1141 
1142 static DecodeStatus DecodeCCOutOperand(MCInst &Inst, unsigned Val,
1143                                uint64_t Address, const void *Decoder) {
1144   if (Val)
1145     Inst.addOperand(MCOperand::createReg(ARM::CPSR));
1146   else
1147     Inst.addOperand(MCOperand::createReg(0));
1148   return MCDisassembler::Success;
1149 }
1150 
1151 static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Val,
1152                                uint64_t Address, const void *Decoder) {
1153   DecodeStatus S = MCDisassembler::Success;
1154 
1155   unsigned Rm = fieldFromInstruction(Val, 0, 4);
1156   unsigned type = fieldFromInstruction(Val, 5, 2);
1157   unsigned imm = fieldFromInstruction(Val, 7, 5);
1158 
1159   // Register-immediate
1160   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
1161     return MCDisassembler::Fail;
1162 
1163   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1164   switch (type) {
1165     case 0:
1166       Shift = ARM_AM::lsl;
1167       break;
1168     case 1:
1169       Shift = ARM_AM::lsr;
1170       break;
1171     case 2:
1172       Shift = ARM_AM::asr;
1173       break;
1174     case 3:
1175       Shift = ARM_AM::ror;
1176       break;
1177   }
1178 
1179   if (Shift == ARM_AM::ror && imm == 0)
1180     Shift = ARM_AM::rrx;
1181 
1182   unsigned Op = Shift | (imm << 3);
1183   Inst.addOperand(MCOperand::createImm(Op));
1184 
1185   return S;
1186 }
1187 
1188 static DecodeStatus DecodeSORegRegOperand(MCInst &Inst, unsigned Val,
1189                                uint64_t Address, const void *Decoder) {
1190   DecodeStatus S = MCDisassembler::Success;
1191 
1192   unsigned Rm = fieldFromInstruction(Val, 0, 4);
1193   unsigned type = fieldFromInstruction(Val, 5, 2);
1194   unsigned Rs = fieldFromInstruction(Val, 8, 4);
1195 
1196   // Register-register
1197   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1198     return MCDisassembler::Fail;
1199   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
1200     return MCDisassembler::Fail;
1201 
1202   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
1203   switch (type) {
1204     case 0:
1205       Shift = ARM_AM::lsl;
1206       break;
1207     case 1:
1208       Shift = ARM_AM::lsr;
1209       break;
1210     case 2:
1211       Shift = ARM_AM::asr;
1212       break;
1213     case 3:
1214       Shift = ARM_AM::ror;
1215       break;
1216   }
1217 
1218   Inst.addOperand(MCOperand::createImm(Shift));
1219 
1220   return S;
1221 }
1222 
1223 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
1224                                  uint64_t Address, const void *Decoder) {
1225   DecodeStatus S = MCDisassembler::Success;
1226 
1227   bool NeedDisjointWriteback = false;
1228   unsigned WritebackReg = 0;
1229   switch (Inst.getOpcode()) {
1230   default:
1231     break;
1232   case ARM::LDMIA_UPD:
1233   case ARM::LDMDB_UPD:
1234   case ARM::LDMIB_UPD:
1235   case ARM::LDMDA_UPD:
1236   case ARM::t2LDMIA_UPD:
1237   case ARM::t2LDMDB_UPD:
1238   case ARM::t2STMIA_UPD:
1239   case ARM::t2STMDB_UPD:
1240     NeedDisjointWriteback = true;
1241     WritebackReg = Inst.getOperand(0).getReg();
1242     break;
1243   }
1244 
1245   // Empty register lists are not allowed.
1246   if (Val == 0) return MCDisassembler::Fail;
1247   for (unsigned i = 0; i < 16; ++i) {
1248     if (Val & (1 << i)) {
1249       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
1250         return MCDisassembler::Fail;
1251       // Writeback not allowed if Rn is in the target list.
1252       if (NeedDisjointWriteback && WritebackReg == Inst.end()[-1].getReg())
1253         Check(S, MCDisassembler::SoftFail);
1254     }
1255   }
1256 
1257   return S;
1258 }
1259 
1260 static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
1261                                  uint64_t Address, const void *Decoder) {
1262   DecodeStatus S = MCDisassembler::Success;
1263 
1264   unsigned Vd = fieldFromInstruction(Val, 8, 5);
1265   unsigned regs = fieldFromInstruction(Val, 0, 8);
1266 
1267   // In case of unpredictable encoding, tweak the operands.
1268   if (regs == 0 || (Vd + regs) > 32) {
1269     regs = Vd + regs > 32 ? 32 - Vd : regs;
1270     regs = std::max( 1u, regs);
1271     S = MCDisassembler::SoftFail;
1272   }
1273 
1274   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
1275     return MCDisassembler::Fail;
1276   for (unsigned i = 0; i < (regs - 1); ++i) {
1277     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1278       return MCDisassembler::Fail;
1279   }
1280 
1281   return S;
1282 }
1283 
1284 static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
1285                                  uint64_t Address, const void *Decoder) {
1286   DecodeStatus S = MCDisassembler::Success;
1287 
1288   unsigned Vd = fieldFromInstruction(Val, 8, 5);
1289   unsigned regs = fieldFromInstruction(Val, 1, 7);
1290 
1291   // In case of unpredictable encoding, tweak the operands.
1292   if (regs == 0 || regs > 16 || (Vd + regs) > 32) {
1293     regs = Vd + regs > 32 ? 32 - Vd : regs;
1294     regs = std::max( 1u, regs);
1295     regs = std::min(16u, regs);
1296     S = MCDisassembler::SoftFail;
1297   }
1298 
1299   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
1300       return MCDisassembler::Fail;
1301   for (unsigned i = 0; i < (regs - 1); ++i) {
1302     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
1303       return MCDisassembler::Fail;
1304   }
1305 
1306   return S;
1307 }
1308 
1309 static DecodeStatus DecodeBitfieldMaskOperand(MCInst &Inst, unsigned Val,
1310                                       uint64_t Address, const void *Decoder) {
1311   // This operand encodes a mask of contiguous zeros between a specified MSB
1312   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
1313   // the mask of all bits LSB-and-lower, and then xor them to create
1314   // the mask of that's all ones on [msb, lsb].  Finally we not it to
1315   // create the final mask.
1316   unsigned msb = fieldFromInstruction(Val, 5, 5);
1317   unsigned lsb = fieldFromInstruction(Val, 0, 5);
1318 
1319   DecodeStatus S = MCDisassembler::Success;
1320   if (lsb > msb) {
1321     Check(S, MCDisassembler::SoftFail);
1322     // The check above will cause the warning for the "potentially undefined
1323     // instruction encoding" but we can't build a bad MCOperand value here
1324     // with a lsb > msb or else printing the MCInst will cause a crash.
1325     lsb = msb;
1326   }
1327 
1328   uint32_t msb_mask = 0xFFFFFFFF;
1329   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;
1330   uint32_t lsb_mask = (1U << lsb) - 1;
1331 
1332   Inst.addOperand(MCOperand::createImm(~(msb_mask ^ lsb_mask)));
1333   return S;
1334 }
1335 
1336 static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
1337                                   uint64_t Address, const void *Decoder) {
1338   DecodeStatus S = MCDisassembler::Success;
1339 
1340   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1341   unsigned CRd = fieldFromInstruction(Insn, 12, 4);
1342   unsigned coproc = fieldFromInstruction(Insn, 8, 4);
1343   unsigned imm = fieldFromInstruction(Insn, 0, 8);
1344   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1345   unsigned U = fieldFromInstruction(Insn, 23, 1);
1346 
1347   switch (Inst.getOpcode()) {
1348     case ARM::LDC_OFFSET:
1349     case ARM::LDC_PRE:
1350     case ARM::LDC_POST:
1351     case ARM::LDC_OPTION:
1352     case ARM::LDCL_OFFSET:
1353     case ARM::LDCL_PRE:
1354     case ARM::LDCL_POST:
1355     case ARM::LDCL_OPTION:
1356     case ARM::STC_OFFSET:
1357     case ARM::STC_PRE:
1358     case ARM::STC_POST:
1359     case ARM::STC_OPTION:
1360     case ARM::STCL_OFFSET:
1361     case ARM::STCL_PRE:
1362     case ARM::STCL_POST:
1363     case ARM::STCL_OPTION:
1364     case ARM::t2LDC_OFFSET:
1365     case ARM::t2LDC_PRE:
1366     case ARM::t2LDC_POST:
1367     case ARM::t2LDC_OPTION:
1368     case ARM::t2LDCL_OFFSET:
1369     case ARM::t2LDCL_PRE:
1370     case ARM::t2LDCL_POST:
1371     case ARM::t2LDCL_OPTION:
1372     case ARM::t2STC_OFFSET:
1373     case ARM::t2STC_PRE:
1374     case ARM::t2STC_POST:
1375     case ARM::t2STC_OPTION:
1376     case ARM::t2STCL_OFFSET:
1377     case ARM::t2STCL_PRE:
1378     case ARM::t2STCL_POST:
1379     case ARM::t2STCL_OPTION:
1380       if (coproc == 0xA || coproc == 0xB)
1381         return MCDisassembler::Fail;
1382       break;
1383     default:
1384       break;
1385   }
1386 
1387   const FeatureBitset &featureBits =
1388     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
1389   if (featureBits[ARM::HasV8Ops] && (coproc != 14))
1390     return MCDisassembler::Fail;
1391 
1392   Inst.addOperand(MCOperand::createImm(coproc));
1393   Inst.addOperand(MCOperand::createImm(CRd));
1394   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1395     return MCDisassembler::Fail;
1396 
1397   switch (Inst.getOpcode()) {
1398     case ARM::t2LDC2_OFFSET:
1399     case ARM::t2LDC2L_OFFSET:
1400     case ARM::t2LDC2_PRE:
1401     case ARM::t2LDC2L_PRE:
1402     case ARM::t2STC2_OFFSET:
1403     case ARM::t2STC2L_OFFSET:
1404     case ARM::t2STC2_PRE:
1405     case ARM::t2STC2L_PRE:
1406     case ARM::LDC2_OFFSET:
1407     case ARM::LDC2L_OFFSET:
1408     case ARM::LDC2_PRE:
1409     case ARM::LDC2L_PRE:
1410     case ARM::STC2_OFFSET:
1411     case ARM::STC2L_OFFSET:
1412     case ARM::STC2_PRE:
1413     case ARM::STC2L_PRE:
1414     case ARM::t2LDC_OFFSET:
1415     case ARM::t2LDCL_OFFSET:
1416     case ARM::t2LDC_PRE:
1417     case ARM::t2LDCL_PRE:
1418     case ARM::t2STC_OFFSET:
1419     case ARM::t2STCL_OFFSET:
1420     case ARM::t2STC_PRE:
1421     case ARM::t2STCL_PRE:
1422     case ARM::LDC_OFFSET:
1423     case ARM::LDCL_OFFSET:
1424     case ARM::LDC_PRE:
1425     case ARM::LDCL_PRE:
1426     case ARM::STC_OFFSET:
1427     case ARM::STCL_OFFSET:
1428     case ARM::STC_PRE:
1429     case ARM::STCL_PRE:
1430       imm = ARM_AM::getAM5Opc(U ? ARM_AM::add : ARM_AM::sub, imm);
1431       Inst.addOperand(MCOperand::createImm(imm));
1432       break;
1433     case ARM::t2LDC2_POST:
1434     case ARM::t2LDC2L_POST:
1435     case ARM::t2STC2_POST:
1436     case ARM::t2STC2L_POST:
1437     case ARM::LDC2_POST:
1438     case ARM::LDC2L_POST:
1439     case ARM::STC2_POST:
1440     case ARM::STC2L_POST:
1441     case ARM::t2LDC_POST:
1442     case ARM::t2LDCL_POST:
1443     case ARM::t2STC_POST:
1444     case ARM::t2STCL_POST:
1445     case ARM::LDC_POST:
1446     case ARM::LDCL_POST:
1447     case ARM::STC_POST:
1448     case ARM::STCL_POST:
1449       imm |= U << 8;
1450       LLVM_FALLTHROUGH;
1451     default:
1452       // The 'option' variant doesn't encode 'U' in the immediate since
1453       // the immediate is unsigned [0,255].
1454       Inst.addOperand(MCOperand::createImm(imm));
1455       break;
1456   }
1457 
1458   switch (Inst.getOpcode()) {
1459     case ARM::LDC_OFFSET:
1460     case ARM::LDC_PRE:
1461     case ARM::LDC_POST:
1462     case ARM::LDC_OPTION:
1463     case ARM::LDCL_OFFSET:
1464     case ARM::LDCL_PRE:
1465     case ARM::LDCL_POST:
1466     case ARM::LDCL_OPTION:
1467     case ARM::STC_OFFSET:
1468     case ARM::STC_PRE:
1469     case ARM::STC_POST:
1470     case ARM::STC_OPTION:
1471     case ARM::STCL_OFFSET:
1472     case ARM::STCL_PRE:
1473     case ARM::STCL_POST:
1474     case ARM::STCL_OPTION:
1475       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1476         return MCDisassembler::Fail;
1477       break;
1478     default:
1479       break;
1480   }
1481 
1482   return S;
1483 }
1484 
1485 static DecodeStatus
1486 DecodeAddrMode2IdxInstruction(MCInst &Inst, unsigned Insn,
1487                               uint64_t Address, const void *Decoder) {
1488   DecodeStatus S = MCDisassembler::Success;
1489 
1490   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1491   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
1492   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1493   unsigned imm = fieldFromInstruction(Insn, 0, 12);
1494   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1495   unsigned reg = fieldFromInstruction(Insn, 25, 1);
1496   unsigned P = fieldFromInstruction(Insn, 24, 1);
1497   unsigned W = fieldFromInstruction(Insn, 21, 1);
1498 
1499   // On stores, the writeback operand precedes Rt.
1500   switch (Inst.getOpcode()) {
1501     case ARM::STR_POST_IMM:
1502     case ARM::STR_POST_REG:
1503     case ARM::STRB_POST_IMM:
1504     case ARM::STRB_POST_REG:
1505     case ARM::STRT_POST_REG:
1506     case ARM::STRT_POST_IMM:
1507     case ARM::STRBT_POST_REG:
1508     case ARM::STRBT_POST_IMM:
1509       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1510         return MCDisassembler::Fail;
1511       break;
1512     default:
1513       break;
1514   }
1515 
1516   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1517     return MCDisassembler::Fail;
1518 
1519   // On loads, the writeback operand comes after Rt.
1520   switch (Inst.getOpcode()) {
1521     case ARM::LDR_POST_IMM:
1522     case ARM::LDR_POST_REG:
1523     case ARM::LDRB_POST_IMM:
1524     case ARM::LDRB_POST_REG:
1525     case ARM::LDRBT_POST_REG:
1526     case ARM::LDRBT_POST_IMM:
1527     case ARM::LDRT_POST_REG:
1528     case ARM::LDRT_POST_IMM:
1529       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1530         return MCDisassembler::Fail;
1531       break;
1532     default:
1533       break;
1534   }
1535 
1536   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1537     return MCDisassembler::Fail;
1538 
1539   ARM_AM::AddrOpc Op = ARM_AM::add;
1540   if (!fieldFromInstruction(Insn, 23, 1))
1541     Op = ARM_AM::sub;
1542 
1543   bool writeback = (P == 0) || (W == 1);
1544   unsigned idx_mode = 0;
1545   if (P && writeback)
1546     idx_mode = ARMII::IndexModePre;
1547   else if (!P && writeback)
1548     idx_mode = ARMII::IndexModePost;
1549 
1550   if (writeback && (Rn == 15 || Rn == Rt))
1551     S = MCDisassembler::SoftFail; // UNPREDICTABLE
1552 
1553   if (reg) {
1554     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1555       return MCDisassembler::Fail;
1556     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
1557     switch( fieldFromInstruction(Insn, 5, 2)) {
1558       case 0:
1559         Opc = ARM_AM::lsl;
1560         break;
1561       case 1:
1562         Opc = ARM_AM::lsr;
1563         break;
1564       case 2:
1565         Opc = ARM_AM::asr;
1566         break;
1567       case 3:
1568         Opc = ARM_AM::ror;
1569         break;
1570       default:
1571         return MCDisassembler::Fail;
1572     }
1573     unsigned amt = fieldFromInstruction(Insn, 7, 5);
1574     if (Opc == ARM_AM::ror && amt == 0)
1575       Opc = ARM_AM::rrx;
1576     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
1577 
1578     Inst.addOperand(MCOperand::createImm(imm));
1579   } else {
1580     Inst.addOperand(MCOperand::createReg(0));
1581     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
1582     Inst.addOperand(MCOperand::createImm(tmp));
1583   }
1584 
1585   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1586     return MCDisassembler::Fail;
1587 
1588   return S;
1589 }
1590 
1591 static DecodeStatus DecodeSORegMemOperand(MCInst &Inst, unsigned Val,
1592                                   uint64_t Address, const void *Decoder) {
1593   DecodeStatus S = MCDisassembler::Success;
1594 
1595   unsigned Rn = fieldFromInstruction(Val, 13, 4);
1596   unsigned Rm = fieldFromInstruction(Val,  0, 4);
1597   unsigned type = fieldFromInstruction(Val, 5, 2);
1598   unsigned imm = fieldFromInstruction(Val, 7, 5);
1599   unsigned U = fieldFromInstruction(Val, 12, 1);
1600 
1601   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
1602   switch (type) {
1603     case 0:
1604       ShOp = ARM_AM::lsl;
1605       break;
1606     case 1:
1607       ShOp = ARM_AM::lsr;
1608       break;
1609     case 2:
1610       ShOp = ARM_AM::asr;
1611       break;
1612     case 3:
1613       ShOp = ARM_AM::ror;
1614       break;
1615   }
1616 
1617   if (ShOp == ARM_AM::ror && imm == 0)
1618     ShOp = ARM_AM::rrx;
1619 
1620   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1621     return MCDisassembler::Fail;
1622   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1623     return MCDisassembler::Fail;
1624   unsigned shift;
1625   if (U)
1626     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
1627   else
1628     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
1629   Inst.addOperand(MCOperand::createImm(shift));
1630 
1631   return S;
1632 }
1633 
1634 static DecodeStatus
1635 DecodeAddrMode3Instruction(MCInst &Inst, unsigned Insn,
1636                            uint64_t Address, const void *Decoder) {
1637   DecodeStatus S = MCDisassembler::Success;
1638 
1639   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
1640   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1641   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1642   unsigned type = fieldFromInstruction(Insn, 22, 1);
1643   unsigned imm = fieldFromInstruction(Insn, 8, 4);
1644   unsigned U = ((~fieldFromInstruction(Insn, 23, 1)) & 1) << 8;
1645   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1646   unsigned W = fieldFromInstruction(Insn, 21, 1);
1647   unsigned P = fieldFromInstruction(Insn, 24, 1);
1648   unsigned Rt2 = Rt + 1;
1649 
1650   bool writeback = (W == 1) | (P == 0);
1651 
1652   // For {LD,ST}RD, Rt must be even, else undefined.
1653   switch (Inst.getOpcode()) {
1654     case ARM::STRD:
1655     case ARM::STRD_PRE:
1656     case ARM::STRD_POST:
1657     case ARM::LDRD:
1658     case ARM::LDRD_PRE:
1659     case ARM::LDRD_POST:
1660       if (Rt & 0x1) S = MCDisassembler::SoftFail;
1661       break;
1662     default:
1663       break;
1664   }
1665   switch (Inst.getOpcode()) {
1666     case ARM::STRD:
1667     case ARM::STRD_PRE:
1668     case ARM::STRD_POST:
1669       if (P == 0 && W == 1)
1670         S = MCDisassembler::SoftFail;
1671 
1672       if (writeback && (Rn == 15 || Rn == Rt || Rn == Rt2))
1673         S = MCDisassembler::SoftFail;
1674       if (type && Rm == 15)
1675         S = MCDisassembler::SoftFail;
1676       if (Rt2 == 15)
1677         S = MCDisassembler::SoftFail;
1678       if (!type && fieldFromInstruction(Insn, 8, 4))
1679         S = MCDisassembler::SoftFail;
1680       break;
1681     case ARM::STRH:
1682     case ARM::STRH_PRE:
1683     case ARM::STRH_POST:
1684       if (Rt == 15)
1685         S = MCDisassembler::SoftFail;
1686       if (writeback && (Rn == 15 || Rn == Rt))
1687         S = MCDisassembler::SoftFail;
1688       if (!type && Rm == 15)
1689         S = MCDisassembler::SoftFail;
1690       break;
1691     case ARM::LDRD:
1692     case ARM::LDRD_PRE:
1693     case ARM::LDRD_POST:
1694       if (type && Rn == 15) {
1695         if (Rt2 == 15)
1696           S = MCDisassembler::SoftFail;
1697         break;
1698       }
1699       if (P == 0 && W == 1)
1700         S = MCDisassembler::SoftFail;
1701       if (!type && (Rt2 == 15 || Rm == 15 || Rm == Rt || Rm == Rt2))
1702         S = MCDisassembler::SoftFail;
1703       if (!type && writeback && Rn == 15)
1704         S = MCDisassembler::SoftFail;
1705       if (writeback && (Rn == Rt || Rn == Rt2))
1706         S = MCDisassembler::SoftFail;
1707       break;
1708     case ARM::LDRH:
1709     case ARM::LDRH_PRE:
1710     case ARM::LDRH_POST:
1711       if (type && Rn == 15) {
1712         if (Rt == 15)
1713           S = MCDisassembler::SoftFail;
1714         break;
1715       }
1716       if (Rt == 15)
1717         S = MCDisassembler::SoftFail;
1718       if (!type && Rm == 15)
1719         S = MCDisassembler::SoftFail;
1720       if (!type && writeback && (Rn == 15 || Rn == Rt))
1721         S = MCDisassembler::SoftFail;
1722       break;
1723     case ARM::LDRSH:
1724     case ARM::LDRSH_PRE:
1725     case ARM::LDRSH_POST:
1726     case ARM::LDRSB:
1727     case ARM::LDRSB_PRE:
1728     case ARM::LDRSB_POST:
1729       if (type && Rn == 15) {
1730         if (Rt == 15)
1731           S = MCDisassembler::SoftFail;
1732         break;
1733       }
1734       if (type && (Rt == 15 || (writeback && Rn == Rt)))
1735         S = MCDisassembler::SoftFail;
1736       if (!type && (Rt == 15 || Rm == 15))
1737         S = MCDisassembler::SoftFail;
1738       if (!type && writeback && (Rn == 15 || Rn == Rt))
1739         S = MCDisassembler::SoftFail;
1740       break;
1741     default:
1742       break;
1743   }
1744 
1745   if (writeback) { // Writeback
1746     if (P)
1747       U |= ARMII::IndexModePre << 9;
1748     else
1749       U |= ARMII::IndexModePost << 9;
1750 
1751     // On stores, the writeback operand precedes Rt.
1752     switch (Inst.getOpcode()) {
1753     case ARM::STRD:
1754     case ARM::STRD_PRE:
1755     case ARM::STRD_POST:
1756     case ARM::STRH:
1757     case ARM::STRH_PRE:
1758     case ARM::STRH_POST:
1759       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1760         return MCDisassembler::Fail;
1761       break;
1762     default:
1763       break;
1764     }
1765   }
1766 
1767   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
1768     return MCDisassembler::Fail;
1769   switch (Inst.getOpcode()) {
1770     case ARM::STRD:
1771     case ARM::STRD_PRE:
1772     case ARM::STRD_POST:
1773     case ARM::LDRD:
1774     case ARM::LDRD_PRE:
1775     case ARM::LDRD_POST:
1776       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
1777         return MCDisassembler::Fail;
1778       break;
1779     default:
1780       break;
1781   }
1782 
1783   if (writeback) {
1784     // On loads, the writeback operand comes after Rt.
1785     switch (Inst.getOpcode()) {
1786     case ARM::LDRD:
1787     case ARM::LDRD_PRE:
1788     case ARM::LDRD_POST:
1789     case ARM::LDRH:
1790     case ARM::LDRH_PRE:
1791     case ARM::LDRH_POST:
1792     case ARM::LDRSH:
1793     case ARM::LDRSH_PRE:
1794     case ARM::LDRSH_POST:
1795     case ARM::LDRSB:
1796     case ARM::LDRSB_PRE:
1797     case ARM::LDRSB_POST:
1798     case ARM::LDRHTr:
1799     case ARM::LDRSBTr:
1800       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1801         return MCDisassembler::Fail;
1802       break;
1803     default:
1804       break;
1805     }
1806   }
1807 
1808   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1809     return MCDisassembler::Fail;
1810 
1811   if (type) {
1812     Inst.addOperand(MCOperand::createReg(0));
1813     Inst.addOperand(MCOperand::createImm(U | (imm << 4) | Rm));
1814   } else {
1815     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
1816     return MCDisassembler::Fail;
1817     Inst.addOperand(MCOperand::createImm(U));
1818   }
1819 
1820   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1821     return MCDisassembler::Fail;
1822 
1823   return S;
1824 }
1825 
1826 static DecodeStatus DecodeRFEInstruction(MCInst &Inst, unsigned Insn,
1827                                  uint64_t Address, const void *Decoder) {
1828   DecodeStatus S = MCDisassembler::Success;
1829 
1830   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1831   unsigned mode = fieldFromInstruction(Insn, 23, 2);
1832 
1833   switch (mode) {
1834     case 0:
1835       mode = ARM_AM::da;
1836       break;
1837     case 1:
1838       mode = ARM_AM::ia;
1839       break;
1840     case 2:
1841       mode = ARM_AM::db;
1842       break;
1843     case 3:
1844       mode = ARM_AM::ib;
1845       break;
1846   }
1847 
1848   Inst.addOperand(MCOperand::createImm(mode));
1849   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1850     return MCDisassembler::Fail;
1851 
1852   return S;
1853 }
1854 
1855 static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
1856                                uint64_t Address, const void *Decoder) {
1857   DecodeStatus S = MCDisassembler::Success;
1858 
1859   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
1860   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
1861   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1862   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1863 
1864   if (pred == 0xF)
1865     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
1866 
1867   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
1868     return MCDisassembler::Fail;
1869   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
1870     return MCDisassembler::Fail;
1871   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
1872     return MCDisassembler::Fail;
1873   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1874     return MCDisassembler::Fail;
1875   return S;
1876 }
1877 
1878 static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst &Inst,
1879                                   unsigned Insn,
1880                                   uint64_t Address, const void *Decoder) {
1881   DecodeStatus S = MCDisassembler::Success;
1882 
1883   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
1884   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1885   unsigned reglist = fieldFromInstruction(Insn, 0, 16);
1886 
1887   if (pred == 0xF) {
1888     // Ambiguous with RFE and SRS
1889     switch (Inst.getOpcode()) {
1890       case ARM::LDMDA:
1891         Inst.setOpcode(ARM::RFEDA);
1892         break;
1893       case ARM::LDMDA_UPD:
1894         Inst.setOpcode(ARM::RFEDA_UPD);
1895         break;
1896       case ARM::LDMDB:
1897         Inst.setOpcode(ARM::RFEDB);
1898         break;
1899       case ARM::LDMDB_UPD:
1900         Inst.setOpcode(ARM::RFEDB_UPD);
1901         break;
1902       case ARM::LDMIA:
1903         Inst.setOpcode(ARM::RFEIA);
1904         break;
1905       case ARM::LDMIA_UPD:
1906         Inst.setOpcode(ARM::RFEIA_UPD);
1907         break;
1908       case ARM::LDMIB:
1909         Inst.setOpcode(ARM::RFEIB);
1910         break;
1911       case ARM::LDMIB_UPD:
1912         Inst.setOpcode(ARM::RFEIB_UPD);
1913         break;
1914       case ARM::STMDA:
1915         Inst.setOpcode(ARM::SRSDA);
1916         break;
1917       case ARM::STMDA_UPD:
1918         Inst.setOpcode(ARM::SRSDA_UPD);
1919         break;
1920       case ARM::STMDB:
1921         Inst.setOpcode(ARM::SRSDB);
1922         break;
1923       case ARM::STMDB_UPD:
1924         Inst.setOpcode(ARM::SRSDB_UPD);
1925         break;
1926       case ARM::STMIA:
1927         Inst.setOpcode(ARM::SRSIA);
1928         break;
1929       case ARM::STMIA_UPD:
1930         Inst.setOpcode(ARM::SRSIA_UPD);
1931         break;
1932       case ARM::STMIB:
1933         Inst.setOpcode(ARM::SRSIB);
1934         break;
1935       case ARM::STMIB_UPD:
1936         Inst.setOpcode(ARM::SRSIB_UPD);
1937         break;
1938       default:
1939         return MCDisassembler::Fail;
1940     }
1941 
1942     // For stores (which become SRS's, the only operand is the mode.
1943     if (fieldFromInstruction(Insn, 20, 1) == 0) {
1944       // Check SRS encoding constraints
1945       if (!(fieldFromInstruction(Insn, 22, 1) == 1 &&
1946             fieldFromInstruction(Insn, 20, 1) == 0))
1947         return MCDisassembler::Fail;
1948 
1949       Inst.addOperand(
1950           MCOperand::createImm(fieldFromInstruction(Insn, 0, 4)));
1951       return S;
1952     }
1953 
1954     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
1955   }
1956 
1957   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1958     return MCDisassembler::Fail;
1959   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
1960     return MCDisassembler::Fail; // Tied
1961   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1962     return MCDisassembler::Fail;
1963   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
1964     return MCDisassembler::Fail;
1965 
1966   return S;
1967 }
1968 
1969 // Check for UNPREDICTABLE predicated ESB instruction
1970 static DecodeStatus DecodeHINTInstruction(MCInst &Inst, unsigned Insn,
1971                                  uint64_t Address, const void *Decoder) {
1972   unsigned pred = fieldFromInstruction(Insn, 28, 4);
1973   unsigned imm8 = fieldFromInstruction(Insn, 0, 8);
1974   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
1975   const FeatureBitset &FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
1976 
1977   DecodeStatus S = MCDisassembler::Success;
1978 
1979   Inst.addOperand(MCOperand::createImm(imm8));
1980 
1981   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
1982     return MCDisassembler::Fail;
1983 
1984   // ESB is unpredictable if pred != AL. Without the RAS extension, it is a NOP,
1985   // so all predicates should be allowed.
1986   if (imm8 == 0x10 && pred != 0xe && ((FeatureBits[ARM::FeatureRAS]) != 0))
1987     S = MCDisassembler::SoftFail;
1988 
1989   return S;
1990 }
1991 
1992 static DecodeStatus DecodeCPSInstruction(MCInst &Inst, unsigned Insn,
1993                                  uint64_t Address, const void *Decoder) {
1994   unsigned imod = fieldFromInstruction(Insn, 18, 2);
1995   unsigned M = fieldFromInstruction(Insn, 17, 1);
1996   unsigned iflags = fieldFromInstruction(Insn, 6, 3);
1997   unsigned mode = fieldFromInstruction(Insn, 0, 5);
1998 
1999   DecodeStatus S = MCDisassembler::Success;
2000 
2001   // This decoder is called from multiple location that do not check
2002   // the full encoding is valid before they do.
2003   if (fieldFromInstruction(Insn, 5, 1) != 0 ||
2004       fieldFromInstruction(Insn, 16, 1) != 0 ||
2005       fieldFromInstruction(Insn, 20, 8) != 0x10)
2006     return MCDisassembler::Fail;
2007 
2008   // imod == '01' --> UNPREDICTABLE
2009   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
2010   // return failure here.  The '01' imod value is unprintable, so there's
2011   // nothing useful we could do even if we returned UNPREDICTABLE.
2012 
2013   if (imod == 1) return MCDisassembler::Fail;
2014 
2015   if (imod && M) {
2016     Inst.setOpcode(ARM::CPS3p);
2017     Inst.addOperand(MCOperand::createImm(imod));
2018     Inst.addOperand(MCOperand::createImm(iflags));
2019     Inst.addOperand(MCOperand::createImm(mode));
2020   } else if (imod && !M) {
2021     Inst.setOpcode(ARM::CPS2p);
2022     Inst.addOperand(MCOperand::createImm(imod));
2023     Inst.addOperand(MCOperand::createImm(iflags));
2024     if (mode) S = MCDisassembler::SoftFail;
2025   } else if (!imod && M) {
2026     Inst.setOpcode(ARM::CPS1p);
2027     Inst.addOperand(MCOperand::createImm(mode));
2028     if (iflags) S = MCDisassembler::SoftFail;
2029   } else {
2030     // imod == '00' && M == '0' --> UNPREDICTABLE
2031     Inst.setOpcode(ARM::CPS1p);
2032     Inst.addOperand(MCOperand::createImm(mode));
2033     S = MCDisassembler::SoftFail;
2034   }
2035 
2036   return S;
2037 }
2038 
2039 static DecodeStatus DecodeT2CPSInstruction(MCInst &Inst, unsigned Insn,
2040                                  uint64_t Address, const void *Decoder) {
2041   unsigned imod = fieldFromInstruction(Insn, 9, 2);
2042   unsigned M = fieldFromInstruction(Insn, 8, 1);
2043   unsigned iflags = fieldFromInstruction(Insn, 5, 3);
2044   unsigned mode = fieldFromInstruction(Insn, 0, 5);
2045 
2046   DecodeStatus S = MCDisassembler::Success;
2047 
2048   // imod == '01' --> UNPREDICTABLE
2049   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
2050   // return failure here.  The '01' imod value is unprintable, so there's
2051   // nothing useful we could do even if we returned UNPREDICTABLE.
2052 
2053   if (imod == 1) return MCDisassembler::Fail;
2054 
2055   if (imod && M) {
2056     Inst.setOpcode(ARM::t2CPS3p);
2057     Inst.addOperand(MCOperand::createImm(imod));
2058     Inst.addOperand(MCOperand::createImm(iflags));
2059     Inst.addOperand(MCOperand::createImm(mode));
2060   } else if (imod && !M) {
2061     Inst.setOpcode(ARM::t2CPS2p);
2062     Inst.addOperand(MCOperand::createImm(imod));
2063     Inst.addOperand(MCOperand::createImm(iflags));
2064     if (mode) S = MCDisassembler::SoftFail;
2065   } else if (!imod && M) {
2066     Inst.setOpcode(ARM::t2CPS1p);
2067     Inst.addOperand(MCOperand::createImm(mode));
2068     if (iflags) S = MCDisassembler::SoftFail;
2069   } else {
2070     // imod == '00' && M == '0' --> this is a HINT instruction
2071     int imm = fieldFromInstruction(Insn, 0, 8);
2072     // HINT are defined only for immediate in [0..4]
2073     if(imm > 4) return MCDisassembler::Fail;
2074     Inst.setOpcode(ARM::t2HINT);
2075     Inst.addOperand(MCOperand::createImm(imm));
2076   }
2077 
2078   return S;
2079 }
2080 
2081 static DecodeStatus DecodeT2MOVTWInstruction(MCInst &Inst, unsigned Insn,
2082                                  uint64_t Address, const void *Decoder) {
2083   DecodeStatus S = MCDisassembler::Success;
2084 
2085   unsigned Rd = fieldFromInstruction(Insn, 8, 4);
2086   unsigned imm = 0;
2087 
2088   imm |= (fieldFromInstruction(Insn, 0, 8) << 0);
2089   imm |= (fieldFromInstruction(Insn, 12, 3) << 8);
2090   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
2091   imm |= (fieldFromInstruction(Insn, 26, 1) << 11);
2092 
2093   if (Inst.getOpcode() == ARM::t2MOVTi16)
2094     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2095       return MCDisassembler::Fail;
2096   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
2097     return MCDisassembler::Fail;
2098 
2099   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
2100     Inst.addOperand(MCOperand::createImm(imm));
2101 
2102   return S;
2103 }
2104 
2105 static DecodeStatus DecodeArmMOVTWInstruction(MCInst &Inst, unsigned Insn,
2106                                  uint64_t Address, const void *Decoder) {
2107   DecodeStatus S = MCDisassembler::Success;
2108 
2109   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2110   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2111   unsigned imm = 0;
2112 
2113   imm |= (fieldFromInstruction(Insn, 0, 12) << 0);
2114   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
2115 
2116   if (Inst.getOpcode() == ARM::MOVTi16)
2117     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2118       return MCDisassembler::Fail;
2119 
2120   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2121     return MCDisassembler::Fail;
2122 
2123   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
2124     Inst.addOperand(MCOperand::createImm(imm));
2125 
2126   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2127     return MCDisassembler::Fail;
2128 
2129   return S;
2130 }
2131 
2132 static DecodeStatus DecodeSMLAInstruction(MCInst &Inst, unsigned Insn,
2133                                  uint64_t Address, const void *Decoder) {
2134   DecodeStatus S = MCDisassembler::Success;
2135 
2136   unsigned Rd = fieldFromInstruction(Insn, 16, 4);
2137   unsigned Rn = fieldFromInstruction(Insn, 0, 4);
2138   unsigned Rm = fieldFromInstruction(Insn, 8, 4);
2139   unsigned Ra = fieldFromInstruction(Insn, 12, 4);
2140   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2141 
2142   if (pred == 0xF)
2143     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
2144 
2145   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
2146     return MCDisassembler::Fail;
2147   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
2148     return MCDisassembler::Fail;
2149   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
2150     return MCDisassembler::Fail;
2151   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
2152     return MCDisassembler::Fail;
2153 
2154   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2155     return MCDisassembler::Fail;
2156 
2157   return S;
2158 }
2159 
2160 static DecodeStatus DecodeTSTInstruction(MCInst &Inst, unsigned Insn,
2161                                   uint64_t Address, const void *Decoder) {
2162   DecodeStatus S = MCDisassembler::Success;
2163 
2164   unsigned Pred = fieldFromInstruction(Insn, 28, 4);
2165   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2166   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2167 
2168   if (Pred == 0xF)
2169     return DecodeSETPANInstruction(Inst, Insn, Address, Decoder);
2170 
2171   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2172     return MCDisassembler::Fail;
2173   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2174     return MCDisassembler::Fail;
2175   if (!Check(S, DecodePredicateOperand(Inst, Pred, Address, Decoder)))
2176     return MCDisassembler::Fail;
2177 
2178   return S;
2179 }
2180 
2181 static DecodeStatus DecodeSETPANInstruction(MCInst &Inst, unsigned Insn,
2182                                   uint64_t Address, const void *Decoder) {
2183   DecodeStatus S = MCDisassembler::Success;
2184 
2185   unsigned Imm = fieldFromInstruction(Insn, 9, 1);
2186 
2187   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
2188   const FeatureBitset &FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
2189 
2190   if (!FeatureBits[ARM::HasV8_1aOps] ||
2191       !FeatureBits[ARM::HasV8Ops])
2192     return MCDisassembler::Fail;
2193 
2194   // Decoder can be called from DecodeTST, which does not check the full
2195   // encoding is valid.
2196   if (fieldFromInstruction(Insn, 20,12) != 0xf11 ||
2197       fieldFromInstruction(Insn, 4,4) != 0)
2198     return MCDisassembler::Fail;
2199   if (fieldFromInstruction(Insn, 10,10) != 0 ||
2200       fieldFromInstruction(Insn, 0,4) != 0)
2201     S = MCDisassembler::SoftFail;
2202 
2203   Inst.setOpcode(ARM::SETPAN);
2204   Inst.addOperand(MCOperand::createImm(Imm));
2205 
2206   return S;
2207 }
2208 
2209 static DecodeStatus DecodeAddrModeImm12Operand(MCInst &Inst, unsigned Val,
2210                            uint64_t Address, const void *Decoder) {
2211   DecodeStatus S = MCDisassembler::Success;
2212 
2213   unsigned add = fieldFromInstruction(Val, 12, 1);
2214   unsigned imm = fieldFromInstruction(Val, 0, 12);
2215   unsigned Rn = fieldFromInstruction(Val, 13, 4);
2216 
2217   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2218     return MCDisassembler::Fail;
2219 
2220   if (!add) imm *= -1;
2221   if (imm == 0 && !add) imm = INT32_MIN;
2222   Inst.addOperand(MCOperand::createImm(imm));
2223   if (Rn == 15)
2224     tryAddingPcLoadReferenceComment(Address, Address + imm + 8, Decoder);
2225 
2226   return S;
2227 }
2228 
2229 static DecodeStatus DecodeAddrMode5Operand(MCInst &Inst, unsigned Val,
2230                                    uint64_t Address, const void *Decoder) {
2231   DecodeStatus S = MCDisassembler::Success;
2232 
2233   unsigned Rn = fieldFromInstruction(Val, 9, 4);
2234   // U == 1 to add imm, 0 to subtract it.
2235   unsigned U = fieldFromInstruction(Val, 8, 1);
2236   unsigned imm = fieldFromInstruction(Val, 0, 8);
2237 
2238   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2239     return MCDisassembler::Fail;
2240 
2241   if (U)
2242     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
2243   else
2244     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
2245 
2246   return S;
2247 }
2248 
2249 static DecodeStatus DecodeAddrMode5FP16Operand(MCInst &Inst, unsigned Val,
2250                                    uint64_t Address, const void *Decoder) {
2251   DecodeStatus S = MCDisassembler::Success;
2252 
2253   unsigned Rn = fieldFromInstruction(Val, 9, 4);
2254   // U == 1 to add imm, 0 to subtract it.
2255   unsigned U = fieldFromInstruction(Val, 8, 1);
2256   unsigned imm = fieldFromInstruction(Val, 0, 8);
2257 
2258   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2259     return MCDisassembler::Fail;
2260 
2261   if (U)
2262     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5FP16Opc(ARM_AM::add, imm)));
2263   else
2264     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5FP16Opc(ARM_AM::sub, imm)));
2265 
2266   return S;
2267 }
2268 
2269 static DecodeStatus DecodeAddrMode7Operand(MCInst &Inst, unsigned Val,
2270                                    uint64_t Address, const void *Decoder) {
2271   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
2272 }
2273 
2274 static DecodeStatus
2275 DecodeT2BInstruction(MCInst &Inst, unsigned Insn,
2276                      uint64_t Address, const void *Decoder) {
2277   DecodeStatus Status = MCDisassembler::Success;
2278 
2279   // Note the J1 and J2 values are from the encoded instruction.  So here
2280   // change them to I1 and I2 values via as documented:
2281   // I1 = NOT(J1 EOR S);
2282   // I2 = NOT(J2 EOR S);
2283   // and build the imm32 with one trailing zero as documented:
2284   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
2285   unsigned S = fieldFromInstruction(Insn, 26, 1);
2286   unsigned J1 = fieldFromInstruction(Insn, 13, 1);
2287   unsigned J2 = fieldFromInstruction(Insn, 11, 1);
2288   unsigned I1 = !(J1 ^ S);
2289   unsigned I2 = !(J2 ^ S);
2290   unsigned imm10 = fieldFromInstruction(Insn, 16, 10);
2291   unsigned imm11 = fieldFromInstruction(Insn, 0, 11);
2292   unsigned tmp = (S << 23) | (I1 << 22) | (I2 << 21) | (imm10 << 11) | imm11;
2293   int imm32 = SignExtend32<25>(tmp << 1);
2294   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
2295                                 true, 4, Inst, Decoder))
2296     Inst.addOperand(MCOperand::createImm(imm32));
2297 
2298   return Status;
2299 }
2300 
2301 static DecodeStatus
2302 DecodeBranchImmInstruction(MCInst &Inst, unsigned Insn,
2303                            uint64_t Address, const void *Decoder) {
2304   DecodeStatus S = MCDisassembler::Success;
2305 
2306   unsigned pred = fieldFromInstruction(Insn, 28, 4);
2307   unsigned imm = fieldFromInstruction(Insn, 0, 24) << 2;
2308 
2309   if (pred == 0xF) {
2310     Inst.setOpcode(ARM::BLXi);
2311     imm |= fieldFromInstruction(Insn, 24, 1) << 1;
2312     if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
2313                                   true, 4, Inst, Decoder))
2314     Inst.addOperand(MCOperand::createImm(SignExtend32<26>(imm)));
2315     return S;
2316   }
2317 
2318   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
2319                                 true, 4, Inst, Decoder))
2320     Inst.addOperand(MCOperand::createImm(SignExtend32<26>(imm)));
2321   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
2322     return MCDisassembler::Fail;
2323 
2324   return S;
2325 }
2326 
2327 static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
2328                                    uint64_t Address, const void *Decoder) {
2329   DecodeStatus S = MCDisassembler::Success;
2330 
2331   unsigned Rm = fieldFromInstruction(Val, 0, 4);
2332   unsigned align = fieldFromInstruction(Val, 4, 2);
2333 
2334   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2335     return MCDisassembler::Fail;
2336   if (!align)
2337     Inst.addOperand(MCOperand::createImm(0));
2338   else
2339     Inst.addOperand(MCOperand::createImm(4 << align));
2340 
2341   return S;
2342 }
2343 
2344 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Insn,
2345                                    uint64_t Address, const void *Decoder) {
2346   DecodeStatus S = MCDisassembler::Success;
2347 
2348   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2349   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2350   unsigned wb = fieldFromInstruction(Insn, 16, 4);
2351   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2352   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
2353   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2354 
2355   // First output register
2356   switch (Inst.getOpcode()) {
2357   case ARM::VLD1q16: case ARM::VLD1q32: case ARM::VLD1q64: case ARM::VLD1q8:
2358   case ARM::VLD1q16wb_fixed: case ARM::VLD1q16wb_register:
2359   case ARM::VLD1q32wb_fixed: case ARM::VLD1q32wb_register:
2360   case ARM::VLD1q64wb_fixed: case ARM::VLD1q64wb_register:
2361   case ARM::VLD1q8wb_fixed: case ARM::VLD1q8wb_register:
2362   case ARM::VLD2d16: case ARM::VLD2d32: case ARM::VLD2d8:
2363   case ARM::VLD2d16wb_fixed: case ARM::VLD2d16wb_register:
2364   case ARM::VLD2d32wb_fixed: case ARM::VLD2d32wb_register:
2365   case ARM::VLD2d8wb_fixed: case ARM::VLD2d8wb_register:
2366     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2367       return MCDisassembler::Fail;
2368     break;
2369   case ARM::VLD2b16:
2370   case ARM::VLD2b32:
2371   case ARM::VLD2b8:
2372   case ARM::VLD2b16wb_fixed:
2373   case ARM::VLD2b16wb_register:
2374   case ARM::VLD2b32wb_fixed:
2375   case ARM::VLD2b32wb_register:
2376   case ARM::VLD2b8wb_fixed:
2377   case ARM::VLD2b8wb_register:
2378     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
2379       return MCDisassembler::Fail;
2380     break;
2381   default:
2382     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2383       return MCDisassembler::Fail;
2384   }
2385 
2386   // Second output register
2387   switch (Inst.getOpcode()) {
2388     case ARM::VLD3d8:
2389     case ARM::VLD3d16:
2390     case ARM::VLD3d32:
2391     case ARM::VLD3d8_UPD:
2392     case ARM::VLD3d16_UPD:
2393     case ARM::VLD3d32_UPD:
2394     case ARM::VLD4d8:
2395     case ARM::VLD4d16:
2396     case ARM::VLD4d32:
2397     case ARM::VLD4d8_UPD:
2398     case ARM::VLD4d16_UPD:
2399     case ARM::VLD4d32_UPD:
2400       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2401         return MCDisassembler::Fail;
2402       break;
2403     case ARM::VLD3q8:
2404     case ARM::VLD3q16:
2405     case ARM::VLD3q32:
2406     case ARM::VLD3q8_UPD:
2407     case ARM::VLD3q16_UPD:
2408     case ARM::VLD3q32_UPD:
2409     case ARM::VLD4q8:
2410     case ARM::VLD4q16:
2411     case ARM::VLD4q32:
2412     case ARM::VLD4q8_UPD:
2413     case ARM::VLD4q16_UPD:
2414     case ARM::VLD4q32_UPD:
2415       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2416         return MCDisassembler::Fail;
2417       break;
2418     default:
2419       break;
2420   }
2421 
2422   // Third output register
2423   switch(Inst.getOpcode()) {
2424     case ARM::VLD3d8:
2425     case ARM::VLD3d16:
2426     case ARM::VLD3d32:
2427     case ARM::VLD3d8_UPD:
2428     case ARM::VLD3d16_UPD:
2429     case ARM::VLD3d32_UPD:
2430     case ARM::VLD4d8:
2431     case ARM::VLD4d16:
2432     case ARM::VLD4d32:
2433     case ARM::VLD4d8_UPD:
2434     case ARM::VLD4d16_UPD:
2435     case ARM::VLD4d32_UPD:
2436       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2437         return MCDisassembler::Fail;
2438       break;
2439     case ARM::VLD3q8:
2440     case ARM::VLD3q16:
2441     case ARM::VLD3q32:
2442     case ARM::VLD3q8_UPD:
2443     case ARM::VLD3q16_UPD:
2444     case ARM::VLD3q32_UPD:
2445     case ARM::VLD4q8:
2446     case ARM::VLD4q16:
2447     case ARM::VLD4q32:
2448     case ARM::VLD4q8_UPD:
2449     case ARM::VLD4q16_UPD:
2450     case ARM::VLD4q32_UPD:
2451       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2452         return MCDisassembler::Fail;
2453       break;
2454     default:
2455       break;
2456   }
2457 
2458   // Fourth output register
2459   switch (Inst.getOpcode()) {
2460     case ARM::VLD4d8:
2461     case ARM::VLD4d16:
2462     case ARM::VLD4d32:
2463     case ARM::VLD4d8_UPD:
2464     case ARM::VLD4d16_UPD:
2465     case ARM::VLD4d32_UPD:
2466       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2467         return MCDisassembler::Fail;
2468       break;
2469     case ARM::VLD4q8:
2470     case ARM::VLD4q16:
2471     case ARM::VLD4q32:
2472     case ARM::VLD4q8_UPD:
2473     case ARM::VLD4q16_UPD:
2474     case ARM::VLD4q32_UPD:
2475       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2476         return MCDisassembler::Fail;
2477       break;
2478     default:
2479       break;
2480   }
2481 
2482   // Writeback operand
2483   switch (Inst.getOpcode()) {
2484     case ARM::VLD1d8wb_fixed:
2485     case ARM::VLD1d16wb_fixed:
2486     case ARM::VLD1d32wb_fixed:
2487     case ARM::VLD1d64wb_fixed:
2488     case ARM::VLD1d8wb_register:
2489     case ARM::VLD1d16wb_register:
2490     case ARM::VLD1d32wb_register:
2491     case ARM::VLD1d64wb_register:
2492     case ARM::VLD1q8wb_fixed:
2493     case ARM::VLD1q16wb_fixed:
2494     case ARM::VLD1q32wb_fixed:
2495     case ARM::VLD1q64wb_fixed:
2496     case ARM::VLD1q8wb_register:
2497     case ARM::VLD1q16wb_register:
2498     case ARM::VLD1q32wb_register:
2499     case ARM::VLD1q64wb_register:
2500     case ARM::VLD1d8Twb_fixed:
2501     case ARM::VLD1d8Twb_register:
2502     case ARM::VLD1d16Twb_fixed:
2503     case ARM::VLD1d16Twb_register:
2504     case ARM::VLD1d32Twb_fixed:
2505     case ARM::VLD1d32Twb_register:
2506     case ARM::VLD1d64Twb_fixed:
2507     case ARM::VLD1d64Twb_register:
2508     case ARM::VLD1d8Qwb_fixed:
2509     case ARM::VLD1d8Qwb_register:
2510     case ARM::VLD1d16Qwb_fixed:
2511     case ARM::VLD1d16Qwb_register:
2512     case ARM::VLD1d32Qwb_fixed:
2513     case ARM::VLD1d32Qwb_register:
2514     case ARM::VLD1d64Qwb_fixed:
2515     case ARM::VLD1d64Qwb_register:
2516     case ARM::VLD2d8wb_fixed:
2517     case ARM::VLD2d16wb_fixed:
2518     case ARM::VLD2d32wb_fixed:
2519     case ARM::VLD2q8wb_fixed:
2520     case ARM::VLD2q16wb_fixed:
2521     case ARM::VLD2q32wb_fixed:
2522     case ARM::VLD2d8wb_register:
2523     case ARM::VLD2d16wb_register:
2524     case ARM::VLD2d32wb_register:
2525     case ARM::VLD2q8wb_register:
2526     case ARM::VLD2q16wb_register:
2527     case ARM::VLD2q32wb_register:
2528     case ARM::VLD2b8wb_fixed:
2529     case ARM::VLD2b16wb_fixed:
2530     case ARM::VLD2b32wb_fixed:
2531     case ARM::VLD2b8wb_register:
2532     case ARM::VLD2b16wb_register:
2533     case ARM::VLD2b32wb_register:
2534       Inst.addOperand(MCOperand::createImm(0));
2535       break;
2536     case ARM::VLD3d8_UPD:
2537     case ARM::VLD3d16_UPD:
2538     case ARM::VLD3d32_UPD:
2539     case ARM::VLD3q8_UPD:
2540     case ARM::VLD3q16_UPD:
2541     case ARM::VLD3q32_UPD:
2542     case ARM::VLD4d8_UPD:
2543     case ARM::VLD4d16_UPD:
2544     case ARM::VLD4d32_UPD:
2545     case ARM::VLD4q8_UPD:
2546     case ARM::VLD4q16_UPD:
2547     case ARM::VLD4q32_UPD:
2548       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2549         return MCDisassembler::Fail;
2550       break;
2551     default:
2552       break;
2553   }
2554 
2555   // AddrMode6 Base (register+alignment)
2556   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2557     return MCDisassembler::Fail;
2558 
2559   // AddrMode6 Offset (register)
2560   switch (Inst.getOpcode()) {
2561   default:
2562     // The below have been updated to have explicit am6offset split
2563     // between fixed and register offset. For those instructions not
2564     // yet updated, we need to add an additional reg0 operand for the
2565     // fixed variant.
2566     //
2567     // The fixed offset encodes as Rm == 0xd, so we check for that.
2568     if (Rm == 0xd) {
2569       Inst.addOperand(MCOperand::createReg(0));
2570       break;
2571     }
2572     // Fall through to handle the register offset variant.
2573     LLVM_FALLTHROUGH;
2574   case ARM::VLD1d8wb_fixed:
2575   case ARM::VLD1d16wb_fixed:
2576   case ARM::VLD1d32wb_fixed:
2577   case ARM::VLD1d64wb_fixed:
2578   case ARM::VLD1d8Twb_fixed:
2579   case ARM::VLD1d16Twb_fixed:
2580   case ARM::VLD1d32Twb_fixed:
2581   case ARM::VLD1d64Twb_fixed:
2582   case ARM::VLD1d8Qwb_fixed:
2583   case ARM::VLD1d16Qwb_fixed:
2584   case ARM::VLD1d32Qwb_fixed:
2585   case ARM::VLD1d64Qwb_fixed:
2586   case ARM::VLD1d8wb_register:
2587   case ARM::VLD1d16wb_register:
2588   case ARM::VLD1d32wb_register:
2589   case ARM::VLD1d64wb_register:
2590   case ARM::VLD1q8wb_fixed:
2591   case ARM::VLD1q16wb_fixed:
2592   case ARM::VLD1q32wb_fixed:
2593   case ARM::VLD1q64wb_fixed:
2594   case ARM::VLD1q8wb_register:
2595   case ARM::VLD1q16wb_register:
2596   case ARM::VLD1q32wb_register:
2597   case ARM::VLD1q64wb_register:
2598     // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2599     // variant encodes Rm == 0xf. Anything else is a register offset post-
2600     // increment and we need to add the register operand to the instruction.
2601     if (Rm != 0xD && Rm != 0xF &&
2602         !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2603       return MCDisassembler::Fail;
2604     break;
2605   case ARM::VLD2d8wb_fixed:
2606   case ARM::VLD2d16wb_fixed:
2607   case ARM::VLD2d32wb_fixed:
2608   case ARM::VLD2b8wb_fixed:
2609   case ARM::VLD2b16wb_fixed:
2610   case ARM::VLD2b32wb_fixed:
2611   case ARM::VLD2q8wb_fixed:
2612   case ARM::VLD2q16wb_fixed:
2613   case ARM::VLD2q32wb_fixed:
2614     break;
2615   }
2616 
2617   return S;
2618 }
2619 
2620 static DecodeStatus DecodeVLDST1Instruction(MCInst &Inst, unsigned Insn,
2621                                    uint64_t Address, const void *Decoder) {
2622   unsigned type = fieldFromInstruction(Insn, 8, 4);
2623   unsigned align = fieldFromInstruction(Insn, 4, 2);
2624   if (type == 6 && (align & 2)) return MCDisassembler::Fail;
2625   if (type == 7 && (align & 2)) return MCDisassembler::Fail;
2626   if (type == 10 && align == 3) return MCDisassembler::Fail;
2627 
2628   unsigned load = fieldFromInstruction(Insn, 21, 1);
2629   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2630               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2631 }
2632 
2633 static DecodeStatus DecodeVLDST2Instruction(MCInst &Inst, unsigned Insn,
2634                                    uint64_t Address, const void *Decoder) {
2635   unsigned size = fieldFromInstruction(Insn, 6, 2);
2636   if (size == 3) return MCDisassembler::Fail;
2637 
2638   unsigned type = fieldFromInstruction(Insn, 8, 4);
2639   unsigned align = fieldFromInstruction(Insn, 4, 2);
2640   if (type == 8 && align == 3) return MCDisassembler::Fail;
2641   if (type == 9 && align == 3) return MCDisassembler::Fail;
2642 
2643   unsigned load = fieldFromInstruction(Insn, 21, 1);
2644   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2645               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2646 }
2647 
2648 static DecodeStatus DecodeVLDST3Instruction(MCInst &Inst, unsigned Insn,
2649                                    uint64_t Address, const void *Decoder) {
2650   unsigned size = fieldFromInstruction(Insn, 6, 2);
2651   if (size == 3) return MCDisassembler::Fail;
2652 
2653   unsigned align = fieldFromInstruction(Insn, 4, 2);
2654   if (align & 2) return MCDisassembler::Fail;
2655 
2656   unsigned load = fieldFromInstruction(Insn, 21, 1);
2657   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2658               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2659 }
2660 
2661 static DecodeStatus DecodeVLDST4Instruction(MCInst &Inst, unsigned Insn,
2662                                    uint64_t Address, const void *Decoder) {
2663   unsigned size = fieldFromInstruction(Insn, 6, 2);
2664   if (size == 3) return MCDisassembler::Fail;
2665 
2666   unsigned load = fieldFromInstruction(Insn, 21, 1);
2667   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
2668               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
2669 }
2670 
2671 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Insn,
2672                                  uint64_t Address, const void *Decoder) {
2673   DecodeStatus S = MCDisassembler::Success;
2674 
2675   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2676   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2677   unsigned wb = fieldFromInstruction(Insn, 16, 4);
2678   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2679   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
2680   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2681 
2682   // Writeback Operand
2683   switch (Inst.getOpcode()) {
2684     case ARM::VST1d8wb_fixed:
2685     case ARM::VST1d16wb_fixed:
2686     case ARM::VST1d32wb_fixed:
2687     case ARM::VST1d64wb_fixed:
2688     case ARM::VST1d8wb_register:
2689     case ARM::VST1d16wb_register:
2690     case ARM::VST1d32wb_register:
2691     case ARM::VST1d64wb_register:
2692     case ARM::VST1q8wb_fixed:
2693     case ARM::VST1q16wb_fixed:
2694     case ARM::VST1q32wb_fixed:
2695     case ARM::VST1q64wb_fixed:
2696     case ARM::VST1q8wb_register:
2697     case ARM::VST1q16wb_register:
2698     case ARM::VST1q32wb_register:
2699     case ARM::VST1q64wb_register:
2700     case ARM::VST1d8Twb_fixed:
2701     case ARM::VST1d16Twb_fixed:
2702     case ARM::VST1d32Twb_fixed:
2703     case ARM::VST1d64Twb_fixed:
2704     case ARM::VST1d8Twb_register:
2705     case ARM::VST1d16Twb_register:
2706     case ARM::VST1d32Twb_register:
2707     case ARM::VST1d64Twb_register:
2708     case ARM::VST1d8Qwb_fixed:
2709     case ARM::VST1d16Qwb_fixed:
2710     case ARM::VST1d32Qwb_fixed:
2711     case ARM::VST1d64Qwb_fixed:
2712     case ARM::VST1d8Qwb_register:
2713     case ARM::VST1d16Qwb_register:
2714     case ARM::VST1d32Qwb_register:
2715     case ARM::VST1d64Qwb_register:
2716     case ARM::VST2d8wb_fixed:
2717     case ARM::VST2d16wb_fixed:
2718     case ARM::VST2d32wb_fixed:
2719     case ARM::VST2d8wb_register:
2720     case ARM::VST2d16wb_register:
2721     case ARM::VST2d32wb_register:
2722     case ARM::VST2q8wb_fixed:
2723     case ARM::VST2q16wb_fixed:
2724     case ARM::VST2q32wb_fixed:
2725     case ARM::VST2q8wb_register:
2726     case ARM::VST2q16wb_register:
2727     case ARM::VST2q32wb_register:
2728     case ARM::VST2b8wb_fixed:
2729     case ARM::VST2b16wb_fixed:
2730     case ARM::VST2b32wb_fixed:
2731     case ARM::VST2b8wb_register:
2732     case ARM::VST2b16wb_register:
2733     case ARM::VST2b32wb_register:
2734       if (Rm == 0xF)
2735         return MCDisassembler::Fail;
2736       Inst.addOperand(MCOperand::createImm(0));
2737       break;
2738     case ARM::VST3d8_UPD:
2739     case ARM::VST3d16_UPD:
2740     case ARM::VST3d32_UPD:
2741     case ARM::VST3q8_UPD:
2742     case ARM::VST3q16_UPD:
2743     case ARM::VST3q32_UPD:
2744     case ARM::VST4d8_UPD:
2745     case ARM::VST4d16_UPD:
2746     case ARM::VST4d32_UPD:
2747     case ARM::VST4q8_UPD:
2748     case ARM::VST4q16_UPD:
2749     case ARM::VST4q32_UPD:
2750       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
2751         return MCDisassembler::Fail;
2752       break;
2753     default:
2754       break;
2755   }
2756 
2757   // AddrMode6 Base (register+alignment)
2758   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
2759     return MCDisassembler::Fail;
2760 
2761   // AddrMode6 Offset (register)
2762   switch (Inst.getOpcode()) {
2763     default:
2764       if (Rm == 0xD)
2765         Inst.addOperand(MCOperand::createReg(0));
2766       else if (Rm != 0xF) {
2767         if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2768           return MCDisassembler::Fail;
2769       }
2770       break;
2771     case ARM::VST1d8wb_fixed:
2772     case ARM::VST1d16wb_fixed:
2773     case ARM::VST1d32wb_fixed:
2774     case ARM::VST1d64wb_fixed:
2775     case ARM::VST1q8wb_fixed:
2776     case ARM::VST1q16wb_fixed:
2777     case ARM::VST1q32wb_fixed:
2778     case ARM::VST1q64wb_fixed:
2779     case ARM::VST1d8Twb_fixed:
2780     case ARM::VST1d16Twb_fixed:
2781     case ARM::VST1d32Twb_fixed:
2782     case ARM::VST1d64Twb_fixed:
2783     case ARM::VST1d8Qwb_fixed:
2784     case ARM::VST1d16Qwb_fixed:
2785     case ARM::VST1d32Qwb_fixed:
2786     case ARM::VST1d64Qwb_fixed:
2787     case ARM::VST2d8wb_fixed:
2788     case ARM::VST2d16wb_fixed:
2789     case ARM::VST2d32wb_fixed:
2790     case ARM::VST2q8wb_fixed:
2791     case ARM::VST2q16wb_fixed:
2792     case ARM::VST2q32wb_fixed:
2793     case ARM::VST2b8wb_fixed:
2794     case ARM::VST2b16wb_fixed:
2795     case ARM::VST2b32wb_fixed:
2796       break;
2797   }
2798 
2799   // First input register
2800   switch (Inst.getOpcode()) {
2801   case ARM::VST1q16:
2802   case ARM::VST1q32:
2803   case ARM::VST1q64:
2804   case ARM::VST1q8:
2805   case ARM::VST1q16wb_fixed:
2806   case ARM::VST1q16wb_register:
2807   case ARM::VST1q32wb_fixed:
2808   case ARM::VST1q32wb_register:
2809   case ARM::VST1q64wb_fixed:
2810   case ARM::VST1q64wb_register:
2811   case ARM::VST1q8wb_fixed:
2812   case ARM::VST1q8wb_register:
2813   case ARM::VST2d16:
2814   case ARM::VST2d32:
2815   case ARM::VST2d8:
2816   case ARM::VST2d16wb_fixed:
2817   case ARM::VST2d16wb_register:
2818   case ARM::VST2d32wb_fixed:
2819   case ARM::VST2d32wb_register:
2820   case ARM::VST2d8wb_fixed:
2821   case ARM::VST2d8wb_register:
2822     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2823       return MCDisassembler::Fail;
2824     break;
2825   case ARM::VST2b16:
2826   case ARM::VST2b32:
2827   case ARM::VST2b8:
2828   case ARM::VST2b16wb_fixed:
2829   case ARM::VST2b16wb_register:
2830   case ARM::VST2b32wb_fixed:
2831   case ARM::VST2b32wb_register:
2832   case ARM::VST2b8wb_fixed:
2833   case ARM::VST2b8wb_register:
2834     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
2835       return MCDisassembler::Fail;
2836     break;
2837   default:
2838     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2839       return MCDisassembler::Fail;
2840   }
2841 
2842   // Second input register
2843   switch (Inst.getOpcode()) {
2844     case ARM::VST3d8:
2845     case ARM::VST3d16:
2846     case ARM::VST3d32:
2847     case ARM::VST3d8_UPD:
2848     case ARM::VST3d16_UPD:
2849     case ARM::VST3d32_UPD:
2850     case ARM::VST4d8:
2851     case ARM::VST4d16:
2852     case ARM::VST4d32:
2853     case ARM::VST4d8_UPD:
2854     case ARM::VST4d16_UPD:
2855     case ARM::VST4d32_UPD:
2856       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
2857         return MCDisassembler::Fail;
2858       break;
2859     case ARM::VST3q8:
2860     case ARM::VST3q16:
2861     case ARM::VST3q32:
2862     case ARM::VST3q8_UPD:
2863     case ARM::VST3q16_UPD:
2864     case ARM::VST3q32_UPD:
2865     case ARM::VST4q8:
2866     case ARM::VST4q16:
2867     case ARM::VST4q32:
2868     case ARM::VST4q8_UPD:
2869     case ARM::VST4q16_UPD:
2870     case ARM::VST4q32_UPD:
2871       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2872         return MCDisassembler::Fail;
2873       break;
2874     default:
2875       break;
2876   }
2877 
2878   // Third input register
2879   switch (Inst.getOpcode()) {
2880     case ARM::VST3d8:
2881     case ARM::VST3d16:
2882     case ARM::VST3d32:
2883     case ARM::VST3d8_UPD:
2884     case ARM::VST3d16_UPD:
2885     case ARM::VST3d32_UPD:
2886     case ARM::VST4d8:
2887     case ARM::VST4d16:
2888     case ARM::VST4d32:
2889     case ARM::VST4d8_UPD:
2890     case ARM::VST4d16_UPD:
2891     case ARM::VST4d32_UPD:
2892       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
2893         return MCDisassembler::Fail;
2894       break;
2895     case ARM::VST3q8:
2896     case ARM::VST3q16:
2897     case ARM::VST3q32:
2898     case ARM::VST3q8_UPD:
2899     case ARM::VST3q16_UPD:
2900     case ARM::VST3q32_UPD:
2901     case ARM::VST4q8:
2902     case ARM::VST4q16:
2903     case ARM::VST4q32:
2904     case ARM::VST4q8_UPD:
2905     case ARM::VST4q16_UPD:
2906     case ARM::VST4q32_UPD:
2907       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
2908         return MCDisassembler::Fail;
2909       break;
2910     default:
2911       break;
2912   }
2913 
2914   // Fourth input register
2915   switch (Inst.getOpcode()) {
2916     case ARM::VST4d8:
2917     case ARM::VST4d16:
2918     case ARM::VST4d32:
2919     case ARM::VST4d8_UPD:
2920     case ARM::VST4d16_UPD:
2921     case ARM::VST4d32_UPD:
2922       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
2923         return MCDisassembler::Fail;
2924       break;
2925     case ARM::VST4q8:
2926     case ARM::VST4q16:
2927     case ARM::VST4q32:
2928     case ARM::VST4q8_UPD:
2929     case ARM::VST4q16_UPD:
2930     case ARM::VST4q32_UPD:
2931       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
2932         return MCDisassembler::Fail;
2933       break;
2934     default:
2935       break;
2936   }
2937 
2938   return S;
2939 }
2940 
2941 static DecodeStatus DecodeVLD1DupInstruction(MCInst &Inst, unsigned Insn,
2942                                     uint64_t Address, const void *Decoder) {
2943   DecodeStatus S = MCDisassembler::Success;
2944 
2945   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2946   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2947   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2948   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2949   unsigned align = fieldFromInstruction(Insn, 4, 1);
2950   unsigned size = fieldFromInstruction(Insn, 6, 2);
2951 
2952   if (size == 0 && align == 1)
2953     return MCDisassembler::Fail;
2954   align *= (1 << size);
2955 
2956   switch (Inst.getOpcode()) {
2957   case ARM::VLD1DUPq16: case ARM::VLD1DUPq32: case ARM::VLD1DUPq8:
2958   case ARM::VLD1DUPq16wb_fixed: case ARM::VLD1DUPq16wb_register:
2959   case ARM::VLD1DUPq32wb_fixed: case ARM::VLD1DUPq32wb_register:
2960   case ARM::VLD1DUPq8wb_fixed: case ARM::VLD1DUPq8wb_register:
2961     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
2962       return MCDisassembler::Fail;
2963     break;
2964   default:
2965     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
2966       return MCDisassembler::Fail;
2967     break;
2968   }
2969   if (Rm != 0xF) {
2970     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2971       return MCDisassembler::Fail;
2972   }
2973 
2974   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
2975     return MCDisassembler::Fail;
2976   Inst.addOperand(MCOperand::createImm(align));
2977 
2978   // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
2979   // variant encodes Rm == 0xf. Anything else is a register offset post-
2980   // increment and we need to add the register operand to the instruction.
2981   if (Rm != 0xD && Rm != 0xF &&
2982       !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
2983     return MCDisassembler::Fail;
2984 
2985   return S;
2986 }
2987 
2988 static DecodeStatus DecodeVLD2DupInstruction(MCInst &Inst, unsigned Insn,
2989                                     uint64_t Address, const void *Decoder) {
2990   DecodeStatus S = MCDisassembler::Success;
2991 
2992   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
2993   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
2994   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
2995   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
2996   unsigned align = fieldFromInstruction(Insn, 4, 1);
2997   unsigned size = 1 << fieldFromInstruction(Insn, 6, 2);
2998   align *= 2*size;
2999 
3000   switch (Inst.getOpcode()) {
3001   case ARM::VLD2DUPd16: case ARM::VLD2DUPd32: case ARM::VLD2DUPd8:
3002   case ARM::VLD2DUPd16wb_fixed: case ARM::VLD2DUPd16wb_register:
3003   case ARM::VLD2DUPd32wb_fixed: case ARM::VLD2DUPd32wb_register:
3004   case ARM::VLD2DUPd8wb_fixed: case ARM::VLD2DUPd8wb_register:
3005     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
3006       return MCDisassembler::Fail;
3007     break;
3008   case ARM::VLD2DUPd16x2: case ARM::VLD2DUPd32x2: case ARM::VLD2DUPd8x2:
3009   case ARM::VLD2DUPd16x2wb_fixed: case ARM::VLD2DUPd16x2wb_register:
3010   case ARM::VLD2DUPd32x2wb_fixed: case ARM::VLD2DUPd32x2wb_register:
3011   case ARM::VLD2DUPd8x2wb_fixed: case ARM::VLD2DUPd8x2wb_register:
3012     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
3013       return MCDisassembler::Fail;
3014     break;
3015   default:
3016     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3017       return MCDisassembler::Fail;
3018     break;
3019   }
3020 
3021   if (Rm != 0xF)
3022     Inst.addOperand(MCOperand::createImm(0));
3023 
3024   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3025     return MCDisassembler::Fail;
3026   Inst.addOperand(MCOperand::createImm(align));
3027 
3028   if (Rm != 0xD && Rm != 0xF) {
3029     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3030       return MCDisassembler::Fail;
3031   }
3032 
3033   return S;
3034 }
3035 
3036 static DecodeStatus DecodeVLD3DupInstruction(MCInst &Inst, unsigned Insn,
3037                                     uint64_t Address, const void *Decoder) {
3038   DecodeStatus S = MCDisassembler::Success;
3039 
3040   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3041   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3042   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3043   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3044   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
3045 
3046   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3047     return MCDisassembler::Fail;
3048   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
3049     return MCDisassembler::Fail;
3050   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
3051     return MCDisassembler::Fail;
3052   if (Rm != 0xF) {
3053     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3054       return MCDisassembler::Fail;
3055   }
3056 
3057   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3058     return MCDisassembler::Fail;
3059   Inst.addOperand(MCOperand::createImm(0));
3060 
3061   if (Rm == 0xD)
3062     Inst.addOperand(MCOperand::createReg(0));
3063   else if (Rm != 0xF) {
3064     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3065       return MCDisassembler::Fail;
3066   }
3067 
3068   return S;
3069 }
3070 
3071 static DecodeStatus DecodeVLD4DupInstruction(MCInst &Inst, unsigned Insn,
3072                                     uint64_t Address, const void *Decoder) {
3073   DecodeStatus S = MCDisassembler::Success;
3074 
3075   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3076   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3077   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3078   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3079   unsigned size = fieldFromInstruction(Insn, 6, 2);
3080   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
3081   unsigned align = fieldFromInstruction(Insn, 4, 1);
3082 
3083   if (size == 0x3) {
3084     if (align == 0)
3085       return MCDisassembler::Fail;
3086     align = 16;
3087   } else {
3088     if (size == 2) {
3089       align *= 8;
3090     } else {
3091       size = 1 << size;
3092       align *= 4*size;
3093     }
3094   }
3095 
3096   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3097     return MCDisassembler::Fail;
3098   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
3099     return MCDisassembler::Fail;
3100   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
3101     return MCDisassembler::Fail;
3102   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
3103     return MCDisassembler::Fail;
3104   if (Rm != 0xF) {
3105     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3106       return MCDisassembler::Fail;
3107   }
3108 
3109   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3110     return MCDisassembler::Fail;
3111   Inst.addOperand(MCOperand::createImm(align));
3112 
3113   if (Rm == 0xD)
3114     Inst.addOperand(MCOperand::createReg(0));
3115   else if (Rm != 0xF) {
3116     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3117       return MCDisassembler::Fail;
3118   }
3119 
3120   return S;
3121 }
3122 
3123 static DecodeStatus
3124 DecodeNEONModImmInstruction(MCInst &Inst, unsigned Insn,
3125                             uint64_t Address, const void *Decoder) {
3126   DecodeStatus S = MCDisassembler::Success;
3127 
3128   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3129   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3130   unsigned imm = fieldFromInstruction(Insn, 0, 4);
3131   imm |= fieldFromInstruction(Insn, 16, 3) << 4;
3132   imm |= fieldFromInstruction(Insn, 24, 1) << 7;
3133   imm |= fieldFromInstruction(Insn, 8, 4) << 8;
3134   imm |= fieldFromInstruction(Insn, 5, 1) << 12;
3135   unsigned Q = fieldFromInstruction(Insn, 6, 1);
3136 
3137   if (Q) {
3138     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3139     return MCDisassembler::Fail;
3140   } else {
3141     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3142     return MCDisassembler::Fail;
3143   }
3144 
3145   Inst.addOperand(MCOperand::createImm(imm));
3146 
3147   switch (Inst.getOpcode()) {
3148     case ARM::VORRiv4i16:
3149     case ARM::VORRiv2i32:
3150     case ARM::VBICiv4i16:
3151     case ARM::VBICiv2i32:
3152       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3153         return MCDisassembler::Fail;
3154       break;
3155     case ARM::VORRiv8i16:
3156     case ARM::VORRiv4i32:
3157     case ARM::VBICiv8i16:
3158     case ARM::VBICiv4i32:
3159       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3160         return MCDisassembler::Fail;
3161       break;
3162     default:
3163       break;
3164   }
3165 
3166   return S;
3167 }
3168 
3169 static DecodeStatus DecodeVSHLMaxInstruction(MCInst &Inst, unsigned Insn,
3170                                         uint64_t Address, const void *Decoder) {
3171   DecodeStatus S = MCDisassembler::Success;
3172 
3173   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3174   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3175   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3176   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
3177   unsigned size = fieldFromInstruction(Insn, 18, 2);
3178 
3179   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
3180     return MCDisassembler::Fail;
3181   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
3182     return MCDisassembler::Fail;
3183   Inst.addOperand(MCOperand::createImm(8 << size));
3184 
3185   return S;
3186 }
3187 
3188 static DecodeStatus DecodeShiftRight8Imm(MCInst &Inst, unsigned Val,
3189                                uint64_t Address, const void *Decoder) {
3190   Inst.addOperand(MCOperand::createImm(8 - Val));
3191   return MCDisassembler::Success;
3192 }
3193 
3194 static DecodeStatus DecodeShiftRight16Imm(MCInst &Inst, unsigned Val,
3195                                uint64_t Address, const void *Decoder) {
3196   Inst.addOperand(MCOperand::createImm(16 - Val));
3197   return MCDisassembler::Success;
3198 }
3199 
3200 static DecodeStatus DecodeShiftRight32Imm(MCInst &Inst, unsigned Val,
3201                                uint64_t Address, const void *Decoder) {
3202   Inst.addOperand(MCOperand::createImm(32 - Val));
3203   return MCDisassembler::Success;
3204 }
3205 
3206 static DecodeStatus DecodeShiftRight64Imm(MCInst &Inst, unsigned Val,
3207                                uint64_t Address, const void *Decoder) {
3208   Inst.addOperand(MCOperand::createImm(64 - Val));
3209   return MCDisassembler::Success;
3210 }
3211 
3212 static DecodeStatus DecodeTBLInstruction(MCInst &Inst, unsigned Insn,
3213                                uint64_t Address, const void *Decoder) {
3214   DecodeStatus S = MCDisassembler::Success;
3215 
3216   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
3217   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
3218   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3219   Rn |= fieldFromInstruction(Insn, 7, 1) << 4;
3220   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3221   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
3222   unsigned op = fieldFromInstruction(Insn, 6, 1);
3223 
3224   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3225     return MCDisassembler::Fail;
3226   if (op) {
3227     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
3228     return MCDisassembler::Fail; // Writeback
3229   }
3230 
3231   switch (Inst.getOpcode()) {
3232   case ARM::VTBL2:
3233   case ARM::VTBX2:
3234     if (!Check(S, DecodeDPairRegisterClass(Inst, Rn, Address, Decoder)))
3235       return MCDisassembler::Fail;
3236     break;
3237   default:
3238     if (!Check(S, DecodeDPRRegisterClass(Inst, Rn, Address, Decoder)))
3239       return MCDisassembler::Fail;
3240   }
3241 
3242   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
3243     return MCDisassembler::Fail;
3244 
3245   return S;
3246 }
3247 
3248 static DecodeStatus DecodeThumbAddSpecialReg(MCInst &Inst, uint16_t Insn,
3249                                      uint64_t Address, const void *Decoder) {
3250   DecodeStatus S = MCDisassembler::Success;
3251 
3252   unsigned dst = fieldFromInstruction(Insn, 8, 3);
3253   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3254 
3255   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
3256     return MCDisassembler::Fail;
3257 
3258   switch(Inst.getOpcode()) {
3259     default:
3260       return MCDisassembler::Fail;
3261     case ARM::tADR:
3262       break; // tADR does not explicitly represent the PC as an operand.
3263     case ARM::tADDrSPi:
3264       Inst.addOperand(MCOperand::createReg(ARM::SP));
3265       break;
3266   }
3267 
3268   Inst.addOperand(MCOperand::createImm(imm));
3269   return S;
3270 }
3271 
3272 static DecodeStatus DecodeThumbBROperand(MCInst &Inst, unsigned Val,
3273                                  uint64_t Address, const void *Decoder) {
3274   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<12>(Val<<1) + 4,
3275                                 true, 2, Inst, Decoder))
3276     Inst.addOperand(MCOperand::createImm(SignExtend32<12>(Val << 1)));
3277   return MCDisassembler::Success;
3278 }
3279 
3280 static DecodeStatus DecodeT2BROperand(MCInst &Inst, unsigned Val,
3281                                  uint64_t Address, const void *Decoder) {
3282   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<21>(Val) + 4,
3283                                 true, 4, Inst, Decoder))
3284     Inst.addOperand(MCOperand::createImm(SignExtend32<21>(Val)));
3285   return MCDisassembler::Success;
3286 }
3287 
3288 static DecodeStatus DecodeThumbCmpBROperand(MCInst &Inst, unsigned Val,
3289                                  uint64_t Address, const void *Decoder) {
3290   if (!tryAddingSymbolicOperand(Address, Address + (Val<<1) + 4,
3291                                 true, 2, Inst, Decoder))
3292     Inst.addOperand(MCOperand::createImm(Val << 1));
3293   return MCDisassembler::Success;
3294 }
3295 
3296 static DecodeStatus DecodeThumbAddrModeRR(MCInst &Inst, unsigned Val,
3297                                  uint64_t Address, const void *Decoder) {
3298   DecodeStatus S = MCDisassembler::Success;
3299 
3300   unsigned Rn = fieldFromInstruction(Val, 0, 3);
3301   unsigned Rm = fieldFromInstruction(Val, 3, 3);
3302 
3303   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
3304     return MCDisassembler::Fail;
3305   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
3306     return MCDisassembler::Fail;
3307 
3308   return S;
3309 }
3310 
3311 static DecodeStatus DecodeThumbAddrModeIS(MCInst &Inst, unsigned Val,
3312                                   uint64_t Address, const void *Decoder) {
3313   DecodeStatus S = MCDisassembler::Success;
3314 
3315   unsigned Rn = fieldFromInstruction(Val, 0, 3);
3316   unsigned imm = fieldFromInstruction(Val, 3, 5);
3317 
3318   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
3319     return MCDisassembler::Fail;
3320   Inst.addOperand(MCOperand::createImm(imm));
3321 
3322   return S;
3323 }
3324 
3325 static DecodeStatus DecodeThumbAddrModePC(MCInst &Inst, unsigned Val,
3326                                   uint64_t Address, const void *Decoder) {
3327   unsigned imm = Val << 2;
3328 
3329   Inst.addOperand(MCOperand::createImm(imm));
3330   tryAddingPcLoadReferenceComment(Address, (Address & ~2u) + imm + 4, Decoder);
3331 
3332   return MCDisassembler::Success;
3333 }
3334 
3335 static DecodeStatus DecodeThumbAddrModeSP(MCInst &Inst, unsigned Val,
3336                                   uint64_t Address, const void *Decoder) {
3337   Inst.addOperand(MCOperand::createReg(ARM::SP));
3338   Inst.addOperand(MCOperand::createImm(Val));
3339 
3340   return MCDisassembler::Success;
3341 }
3342 
3343 static DecodeStatus DecodeT2AddrModeSOReg(MCInst &Inst, unsigned Val,
3344                                   uint64_t Address, const void *Decoder) {
3345   DecodeStatus S = MCDisassembler::Success;
3346 
3347   unsigned Rn = fieldFromInstruction(Val, 6, 4);
3348   unsigned Rm = fieldFromInstruction(Val, 2, 4);
3349   unsigned imm = fieldFromInstruction(Val, 0, 2);
3350 
3351   // Thumb stores cannot use PC as dest register.
3352   switch (Inst.getOpcode()) {
3353   case ARM::t2STRHs:
3354   case ARM::t2STRBs:
3355   case ARM::t2STRs:
3356     if (Rn == 15)
3357       return MCDisassembler::Fail;
3358     break;
3359   default:
3360     break;
3361   }
3362 
3363   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3364     return MCDisassembler::Fail;
3365   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
3366     return MCDisassembler::Fail;
3367   Inst.addOperand(MCOperand::createImm(imm));
3368 
3369   return S;
3370 }
3371 
3372 static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Insn,
3373                               uint64_t Address, const void *Decoder) {
3374   DecodeStatus S = MCDisassembler::Success;
3375 
3376   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3377   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3378 
3379   const FeatureBitset &featureBits =
3380     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3381 
3382   bool hasMP = featureBits[ARM::FeatureMP];
3383   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3384 
3385   if (Rn == 15) {
3386     switch (Inst.getOpcode()) {
3387     case ARM::t2LDRBs:
3388       Inst.setOpcode(ARM::t2LDRBpci);
3389       break;
3390     case ARM::t2LDRHs:
3391       Inst.setOpcode(ARM::t2LDRHpci);
3392       break;
3393     case ARM::t2LDRSHs:
3394       Inst.setOpcode(ARM::t2LDRSHpci);
3395       break;
3396     case ARM::t2LDRSBs:
3397       Inst.setOpcode(ARM::t2LDRSBpci);
3398       break;
3399     case ARM::t2LDRs:
3400       Inst.setOpcode(ARM::t2LDRpci);
3401       break;
3402     case ARM::t2PLDs:
3403       Inst.setOpcode(ARM::t2PLDpci);
3404       break;
3405     case ARM::t2PLIs:
3406       Inst.setOpcode(ARM::t2PLIpci);
3407       break;
3408     default:
3409       return MCDisassembler::Fail;
3410     }
3411 
3412     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3413   }
3414 
3415   if (Rt == 15) {
3416     switch (Inst.getOpcode()) {
3417     case ARM::t2LDRSHs:
3418       return MCDisassembler::Fail;
3419     case ARM::t2LDRHs:
3420       Inst.setOpcode(ARM::t2PLDWs);
3421       break;
3422     case ARM::t2LDRSBs:
3423       Inst.setOpcode(ARM::t2PLIs);
3424       break;
3425     default:
3426       break;
3427     }
3428   }
3429 
3430   switch (Inst.getOpcode()) {
3431     case ARM::t2PLDs:
3432       break;
3433     case ARM::t2PLIs:
3434       if (!hasV7Ops)
3435         return MCDisassembler::Fail;
3436       break;
3437     case ARM::t2PLDWs:
3438       if (!hasV7Ops || !hasMP)
3439         return MCDisassembler::Fail;
3440       break;
3441     default:
3442       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3443         return MCDisassembler::Fail;
3444   }
3445 
3446   unsigned addrmode = fieldFromInstruction(Insn, 4, 2);
3447   addrmode |= fieldFromInstruction(Insn, 0, 4) << 2;
3448   addrmode |= fieldFromInstruction(Insn, 16, 4) << 6;
3449   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
3450     return MCDisassembler::Fail;
3451 
3452   return S;
3453 }
3454 
3455 static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
3456                                 uint64_t Address, const void* Decoder) {
3457   DecodeStatus S = MCDisassembler::Success;
3458 
3459   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3460   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3461   unsigned U = fieldFromInstruction(Insn, 9, 1);
3462   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3463   imm |= (U << 8);
3464   imm |= (Rn << 9);
3465   unsigned add = fieldFromInstruction(Insn, 9, 1);
3466 
3467   const FeatureBitset &featureBits =
3468     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3469 
3470   bool hasMP = featureBits[ARM::FeatureMP];
3471   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3472 
3473   if (Rn == 15) {
3474     switch (Inst.getOpcode()) {
3475     case ARM::t2LDRi8:
3476       Inst.setOpcode(ARM::t2LDRpci);
3477       break;
3478     case ARM::t2LDRBi8:
3479       Inst.setOpcode(ARM::t2LDRBpci);
3480       break;
3481     case ARM::t2LDRSBi8:
3482       Inst.setOpcode(ARM::t2LDRSBpci);
3483       break;
3484     case ARM::t2LDRHi8:
3485       Inst.setOpcode(ARM::t2LDRHpci);
3486       break;
3487     case ARM::t2LDRSHi8:
3488       Inst.setOpcode(ARM::t2LDRSHpci);
3489       break;
3490     case ARM::t2PLDi8:
3491       Inst.setOpcode(ARM::t2PLDpci);
3492       break;
3493     case ARM::t2PLIi8:
3494       Inst.setOpcode(ARM::t2PLIpci);
3495       break;
3496     default:
3497       return MCDisassembler::Fail;
3498     }
3499     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3500   }
3501 
3502   if (Rt == 15) {
3503     switch (Inst.getOpcode()) {
3504     case ARM::t2LDRSHi8:
3505       return MCDisassembler::Fail;
3506     case ARM::t2LDRHi8:
3507       if (!add)
3508         Inst.setOpcode(ARM::t2PLDWi8);
3509       break;
3510     case ARM::t2LDRSBi8:
3511       Inst.setOpcode(ARM::t2PLIi8);
3512       break;
3513     default:
3514       break;
3515     }
3516   }
3517 
3518   switch (Inst.getOpcode()) {
3519   case ARM::t2PLDi8:
3520     break;
3521   case ARM::t2PLIi8:
3522     if (!hasV7Ops)
3523       return MCDisassembler::Fail;
3524     break;
3525   case ARM::t2PLDWi8:
3526       if (!hasV7Ops || !hasMP)
3527         return MCDisassembler::Fail;
3528       break;
3529   default:
3530     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3531       return MCDisassembler::Fail;
3532   }
3533 
3534   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
3535     return MCDisassembler::Fail;
3536   return S;
3537 }
3538 
3539 static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
3540                                 uint64_t Address, const void* Decoder) {
3541   DecodeStatus S = MCDisassembler::Success;
3542 
3543   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3544   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3545   unsigned imm = fieldFromInstruction(Insn, 0, 12);
3546   imm |= (Rn << 13);
3547 
3548   const FeatureBitset &featureBits =
3549     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3550 
3551   bool hasMP = featureBits[ARM::FeatureMP];
3552   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3553 
3554   if (Rn == 15) {
3555     switch (Inst.getOpcode()) {
3556     case ARM::t2LDRi12:
3557       Inst.setOpcode(ARM::t2LDRpci);
3558       break;
3559     case ARM::t2LDRHi12:
3560       Inst.setOpcode(ARM::t2LDRHpci);
3561       break;
3562     case ARM::t2LDRSHi12:
3563       Inst.setOpcode(ARM::t2LDRSHpci);
3564       break;
3565     case ARM::t2LDRBi12:
3566       Inst.setOpcode(ARM::t2LDRBpci);
3567       break;
3568     case ARM::t2LDRSBi12:
3569       Inst.setOpcode(ARM::t2LDRSBpci);
3570       break;
3571     case ARM::t2PLDi12:
3572       Inst.setOpcode(ARM::t2PLDpci);
3573       break;
3574     case ARM::t2PLIi12:
3575       Inst.setOpcode(ARM::t2PLIpci);
3576       break;
3577     default:
3578       return MCDisassembler::Fail;
3579     }
3580     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3581   }
3582 
3583   if (Rt == 15) {
3584     switch (Inst.getOpcode()) {
3585     case ARM::t2LDRSHi12:
3586       return MCDisassembler::Fail;
3587     case ARM::t2LDRHi12:
3588       Inst.setOpcode(ARM::t2PLDWi12);
3589       break;
3590     case ARM::t2LDRSBi12:
3591       Inst.setOpcode(ARM::t2PLIi12);
3592       break;
3593     default:
3594       break;
3595     }
3596   }
3597 
3598   switch (Inst.getOpcode()) {
3599   case ARM::t2PLDi12:
3600     break;
3601   case ARM::t2PLIi12:
3602     if (!hasV7Ops)
3603       return MCDisassembler::Fail;
3604     break;
3605   case ARM::t2PLDWi12:
3606       if (!hasV7Ops || !hasMP)
3607         return MCDisassembler::Fail;
3608       break;
3609   default:
3610     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3611       return MCDisassembler::Fail;
3612   }
3613 
3614   if (!Check(S, DecodeT2AddrModeImm12(Inst, imm, Address, Decoder)))
3615     return MCDisassembler::Fail;
3616   return S;
3617 }
3618 
3619 static DecodeStatus DecodeT2LoadT(MCInst &Inst, unsigned Insn,
3620                                 uint64_t Address, const void* Decoder) {
3621   DecodeStatus S = MCDisassembler::Success;
3622 
3623   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3624   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3625   unsigned imm = fieldFromInstruction(Insn, 0, 8);
3626   imm |= (Rn << 9);
3627 
3628   if (Rn == 15) {
3629     switch (Inst.getOpcode()) {
3630     case ARM::t2LDRT:
3631       Inst.setOpcode(ARM::t2LDRpci);
3632       break;
3633     case ARM::t2LDRBT:
3634       Inst.setOpcode(ARM::t2LDRBpci);
3635       break;
3636     case ARM::t2LDRHT:
3637       Inst.setOpcode(ARM::t2LDRHpci);
3638       break;
3639     case ARM::t2LDRSBT:
3640       Inst.setOpcode(ARM::t2LDRSBpci);
3641       break;
3642     case ARM::t2LDRSHT:
3643       Inst.setOpcode(ARM::t2LDRSHpci);
3644       break;
3645     default:
3646       return MCDisassembler::Fail;
3647     }
3648     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3649   }
3650 
3651   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
3652     return MCDisassembler::Fail;
3653   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
3654     return MCDisassembler::Fail;
3655   return S;
3656 }
3657 
3658 static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
3659                                 uint64_t Address, const void* Decoder) {
3660   DecodeStatus S = MCDisassembler::Success;
3661 
3662   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3663   unsigned U = fieldFromInstruction(Insn, 23, 1);
3664   int imm = fieldFromInstruction(Insn, 0, 12);
3665 
3666   const FeatureBitset &featureBits =
3667     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3668 
3669   bool hasV7Ops = featureBits[ARM::HasV7Ops];
3670 
3671   if (Rt == 15) {
3672     switch (Inst.getOpcode()) {
3673       case ARM::t2LDRBpci:
3674       case ARM::t2LDRHpci:
3675         Inst.setOpcode(ARM::t2PLDpci);
3676         break;
3677       case ARM::t2LDRSBpci:
3678         Inst.setOpcode(ARM::t2PLIpci);
3679         break;
3680       case ARM::t2LDRSHpci:
3681         return MCDisassembler::Fail;
3682       default:
3683         break;
3684     }
3685   }
3686 
3687   switch(Inst.getOpcode()) {
3688   case ARM::t2PLDpci:
3689     break;
3690   case ARM::t2PLIpci:
3691     if (!hasV7Ops)
3692       return MCDisassembler::Fail;
3693     break;
3694   default:
3695     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3696       return MCDisassembler::Fail;
3697   }
3698 
3699   if (!U) {
3700     // Special case for #-0.
3701     if (imm == 0)
3702       imm = INT32_MIN;
3703     else
3704       imm = -imm;
3705   }
3706   Inst.addOperand(MCOperand::createImm(imm));
3707 
3708   return S;
3709 }
3710 
3711 static DecodeStatus DecodeT2Imm8S4(MCInst &Inst, unsigned Val,
3712                            uint64_t Address, const void *Decoder) {
3713   if (Val == 0)
3714     Inst.addOperand(MCOperand::createImm(INT32_MIN));
3715   else {
3716     int imm = Val & 0xFF;
3717 
3718     if (!(Val & 0x100)) imm *= -1;
3719     Inst.addOperand(MCOperand::createImm(imm * 4));
3720   }
3721 
3722   return MCDisassembler::Success;
3723 }
3724 
3725 static DecodeStatus DecodeT2AddrModeImm8s4(MCInst &Inst, unsigned Val,
3726                                    uint64_t Address, const void *Decoder) {
3727   DecodeStatus S = MCDisassembler::Success;
3728 
3729   unsigned Rn = fieldFromInstruction(Val, 9, 4);
3730   unsigned imm = fieldFromInstruction(Val, 0, 9);
3731 
3732   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3733     return MCDisassembler::Fail;
3734   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
3735     return MCDisassembler::Fail;
3736 
3737   return S;
3738 }
3739 
3740 static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst &Inst,unsigned Val,
3741                                    uint64_t Address, const void *Decoder) {
3742   DecodeStatus S = MCDisassembler::Success;
3743 
3744   unsigned Rn = fieldFromInstruction(Val, 8, 4);
3745   unsigned imm = fieldFromInstruction(Val, 0, 8);
3746 
3747   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
3748     return MCDisassembler::Fail;
3749 
3750   Inst.addOperand(MCOperand::createImm(imm));
3751 
3752   return S;
3753 }
3754 
3755 static DecodeStatus DecodeT2Imm8(MCInst &Inst, unsigned Val,
3756                          uint64_t Address, const void *Decoder) {
3757   int imm = Val & 0xFF;
3758   if (Val == 0)
3759     imm = INT32_MIN;
3760   else if (!(Val & 0x100))
3761     imm *= -1;
3762   Inst.addOperand(MCOperand::createImm(imm));
3763 
3764   return MCDisassembler::Success;
3765 }
3766 
3767 static DecodeStatus DecodeT2AddrModeImm8(MCInst &Inst, unsigned Val,
3768                                  uint64_t Address, const void *Decoder) {
3769   DecodeStatus S = MCDisassembler::Success;
3770 
3771   unsigned Rn = fieldFromInstruction(Val, 9, 4);
3772   unsigned imm = fieldFromInstruction(Val, 0, 9);
3773 
3774   // Thumb stores cannot use PC as dest register.
3775   switch (Inst.getOpcode()) {
3776   case ARM::t2STRT:
3777   case ARM::t2STRBT:
3778   case ARM::t2STRHT:
3779   case ARM::t2STRi8:
3780   case ARM::t2STRHi8:
3781   case ARM::t2STRBi8:
3782     if (Rn == 15)
3783       return MCDisassembler::Fail;
3784     break;
3785   default:
3786     break;
3787   }
3788 
3789   // Some instructions always use an additive offset.
3790   switch (Inst.getOpcode()) {
3791     case ARM::t2LDRT:
3792     case ARM::t2LDRBT:
3793     case ARM::t2LDRHT:
3794     case ARM::t2LDRSBT:
3795     case ARM::t2LDRSHT:
3796     case ARM::t2STRT:
3797     case ARM::t2STRBT:
3798     case ARM::t2STRHT:
3799       imm |= 0x100;
3800       break;
3801     default:
3802       break;
3803   }
3804 
3805   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3806     return MCDisassembler::Fail;
3807   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
3808     return MCDisassembler::Fail;
3809 
3810   return S;
3811 }
3812 
3813 static DecodeStatus DecodeT2LdStPre(MCInst &Inst, unsigned Insn,
3814                                     uint64_t Address, const void *Decoder) {
3815   DecodeStatus S = MCDisassembler::Success;
3816 
3817   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
3818   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
3819   unsigned addr = fieldFromInstruction(Insn, 0, 8);
3820   addr |= fieldFromInstruction(Insn, 9, 1) << 8;
3821   addr |= Rn << 9;
3822   unsigned load = fieldFromInstruction(Insn, 20, 1);
3823 
3824   if (Rn == 15) {
3825     switch (Inst.getOpcode()) {
3826     case ARM::t2LDR_PRE:
3827     case ARM::t2LDR_POST:
3828       Inst.setOpcode(ARM::t2LDRpci);
3829       break;
3830     case ARM::t2LDRB_PRE:
3831     case ARM::t2LDRB_POST:
3832       Inst.setOpcode(ARM::t2LDRBpci);
3833       break;
3834     case ARM::t2LDRH_PRE:
3835     case ARM::t2LDRH_POST:
3836       Inst.setOpcode(ARM::t2LDRHpci);
3837       break;
3838     case ARM::t2LDRSB_PRE:
3839     case ARM::t2LDRSB_POST:
3840       if (Rt == 15)
3841         Inst.setOpcode(ARM::t2PLIpci);
3842       else
3843         Inst.setOpcode(ARM::t2LDRSBpci);
3844       break;
3845     case ARM::t2LDRSH_PRE:
3846     case ARM::t2LDRSH_POST:
3847       Inst.setOpcode(ARM::t2LDRSHpci);
3848       break;
3849     default:
3850       return MCDisassembler::Fail;
3851     }
3852     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
3853   }
3854 
3855   if (!load) {
3856     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3857       return MCDisassembler::Fail;
3858   }
3859 
3860   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
3861     return MCDisassembler::Fail;
3862 
3863   if (load) {
3864     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3865       return MCDisassembler::Fail;
3866   }
3867 
3868   if (!Check(S, DecodeT2AddrModeImm8(Inst, addr, Address, Decoder)))
3869     return MCDisassembler::Fail;
3870 
3871   return S;
3872 }
3873 
3874 static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
3875                                   uint64_t Address, const void *Decoder) {
3876   DecodeStatus S = MCDisassembler::Success;
3877 
3878   unsigned Rn = fieldFromInstruction(Val, 13, 4);
3879   unsigned imm = fieldFromInstruction(Val, 0, 12);
3880 
3881   // Thumb stores cannot use PC as dest register.
3882   switch (Inst.getOpcode()) {
3883   case ARM::t2STRi12:
3884   case ARM::t2STRBi12:
3885   case ARM::t2STRHi12:
3886     if (Rn == 15)
3887       return MCDisassembler::Fail;
3888     break;
3889   default:
3890     break;
3891   }
3892 
3893   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
3894     return MCDisassembler::Fail;
3895   Inst.addOperand(MCOperand::createImm(imm));
3896 
3897   return S;
3898 }
3899 
3900 static DecodeStatus DecodeThumbAddSPImm(MCInst &Inst, uint16_t Insn,
3901                                 uint64_t Address, const void *Decoder) {
3902   unsigned imm = fieldFromInstruction(Insn, 0, 7);
3903 
3904   Inst.addOperand(MCOperand::createReg(ARM::SP));
3905   Inst.addOperand(MCOperand::createReg(ARM::SP));
3906   Inst.addOperand(MCOperand::createImm(imm));
3907 
3908   return MCDisassembler::Success;
3909 }
3910 
3911 static DecodeStatus DecodeThumbAddSPReg(MCInst &Inst, uint16_t Insn,
3912                                 uint64_t Address, const void *Decoder) {
3913   DecodeStatus S = MCDisassembler::Success;
3914 
3915   if (Inst.getOpcode() == ARM::tADDrSP) {
3916     unsigned Rdm = fieldFromInstruction(Insn, 0, 3);
3917     Rdm |= fieldFromInstruction(Insn, 7, 1) << 3;
3918 
3919     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
3920     return MCDisassembler::Fail;
3921     Inst.addOperand(MCOperand::createReg(ARM::SP));
3922     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
3923     return MCDisassembler::Fail;
3924   } else if (Inst.getOpcode() == ARM::tADDspr) {
3925     unsigned Rm = fieldFromInstruction(Insn, 3, 4);
3926 
3927     Inst.addOperand(MCOperand::createReg(ARM::SP));
3928     Inst.addOperand(MCOperand::createReg(ARM::SP));
3929     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
3930     return MCDisassembler::Fail;
3931   }
3932 
3933   return S;
3934 }
3935 
3936 static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
3937                            uint64_t Address, const void *Decoder) {
3938   unsigned imod = fieldFromInstruction(Insn, 4, 1) | 0x2;
3939   unsigned flags = fieldFromInstruction(Insn, 0, 3);
3940 
3941   Inst.addOperand(MCOperand::createImm(imod));
3942   Inst.addOperand(MCOperand::createImm(flags));
3943 
3944   return MCDisassembler::Success;
3945 }
3946 
3947 static DecodeStatus DecodePostIdxReg(MCInst &Inst, unsigned Insn,
3948                              uint64_t Address, const void *Decoder) {
3949   DecodeStatus S = MCDisassembler::Success;
3950   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
3951   unsigned add = fieldFromInstruction(Insn, 4, 1);
3952 
3953   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
3954     return MCDisassembler::Fail;
3955   Inst.addOperand(MCOperand::createImm(add));
3956 
3957   return S;
3958 }
3959 
3960 static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Val,
3961                                  uint64_t Address, const void *Decoder) {
3962   // Val is passed in as S:J1:J2:imm10H:imm10L:'0'
3963   // Note only one trailing zero not two.  Also the J1 and J2 values are from
3964   // the encoded instruction.  So here change to I1 and I2 values via:
3965   // I1 = NOT(J1 EOR S);
3966   // I2 = NOT(J2 EOR S);
3967   // and build the imm32 with two trailing zeros as documented:
3968   // imm32 = SignExtend(S:I1:I2:imm10H:imm10L:'00', 32);
3969   unsigned S = (Val >> 23) & 1;
3970   unsigned J1 = (Val >> 22) & 1;
3971   unsigned J2 = (Val >> 21) & 1;
3972   unsigned I1 = !(J1 ^ S);
3973   unsigned I2 = !(J2 ^ S);
3974   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
3975   int imm32 = SignExtend32<25>(tmp << 1);
3976 
3977   if (!tryAddingSymbolicOperand(Address,
3978                                 (Address & ~2u) + imm32 + 4,
3979                                 true, 4, Inst, Decoder))
3980     Inst.addOperand(MCOperand::createImm(imm32));
3981   return MCDisassembler::Success;
3982 }
3983 
3984 static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Val,
3985                               uint64_t Address, const void *Decoder) {
3986   if (Val == 0xA || Val == 0xB)
3987     return MCDisassembler::Fail;
3988 
3989   const FeatureBitset &featureBits =
3990     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
3991 
3992   if (featureBits[ARM::HasV8Ops] && !(Val == 14 || Val == 15))
3993     return MCDisassembler::Fail;
3994 
3995   Inst.addOperand(MCOperand::createImm(Val));
3996   return MCDisassembler::Success;
3997 }
3998 
3999 static DecodeStatus
4000 DecodeThumbTableBranch(MCInst &Inst, unsigned Insn,
4001                        uint64_t Address, const void *Decoder) {
4002   DecodeStatus S = MCDisassembler::Success;
4003 
4004   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4005   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4006 
4007   if (Rn == ARM::SP) S = MCDisassembler::SoftFail;
4008   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4009     return MCDisassembler::Fail;
4010   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
4011     return MCDisassembler::Fail;
4012   return S;
4013 }
4014 
4015 static DecodeStatus
4016 DecodeThumb2BCCInstruction(MCInst &Inst, unsigned Insn,
4017                            uint64_t Address, const void *Decoder) {
4018   DecodeStatus S = MCDisassembler::Success;
4019 
4020   unsigned pred = fieldFromInstruction(Insn, 22, 4);
4021   if (pred == 0xE || pred == 0xF) {
4022     unsigned opc = fieldFromInstruction(Insn, 4, 28);
4023     switch (opc) {
4024       default:
4025         return MCDisassembler::Fail;
4026       case 0xf3bf8f4:
4027         Inst.setOpcode(ARM::t2DSB);
4028         break;
4029       case 0xf3bf8f5:
4030         Inst.setOpcode(ARM::t2DMB);
4031         break;
4032       case 0xf3bf8f6:
4033         Inst.setOpcode(ARM::t2ISB);
4034         break;
4035     }
4036 
4037     unsigned imm = fieldFromInstruction(Insn, 0, 4);
4038     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
4039   }
4040 
4041   unsigned brtarget = fieldFromInstruction(Insn, 0, 11) << 1;
4042   brtarget |= fieldFromInstruction(Insn, 11, 1) << 19;
4043   brtarget |= fieldFromInstruction(Insn, 13, 1) << 18;
4044   brtarget |= fieldFromInstruction(Insn, 16, 6) << 12;
4045   brtarget |= fieldFromInstruction(Insn, 26, 1) << 20;
4046 
4047   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
4048     return MCDisassembler::Fail;
4049   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4050     return MCDisassembler::Fail;
4051 
4052   return S;
4053 }
4054 
4055 // Decode a shifted immediate operand.  These basically consist
4056 // of an 8-bit value, and a 4-bit directive that specifies either
4057 // a splat operation or a rotation.
4058 static DecodeStatus DecodeT2SOImm(MCInst &Inst, unsigned Val,
4059                           uint64_t Address, const void *Decoder) {
4060   unsigned ctrl = fieldFromInstruction(Val, 10, 2);
4061   if (ctrl == 0) {
4062     unsigned byte = fieldFromInstruction(Val, 8, 2);
4063     unsigned imm = fieldFromInstruction(Val, 0, 8);
4064     switch (byte) {
4065       case 0:
4066         Inst.addOperand(MCOperand::createImm(imm));
4067         break;
4068       case 1:
4069         Inst.addOperand(MCOperand::createImm((imm << 16) | imm));
4070         break;
4071       case 2:
4072         Inst.addOperand(MCOperand::createImm((imm << 24) | (imm << 8)));
4073         break;
4074       case 3:
4075         Inst.addOperand(MCOperand::createImm((imm << 24) | (imm << 16) |
4076                                              (imm << 8)  |  imm));
4077         break;
4078     }
4079   } else {
4080     unsigned unrot = fieldFromInstruction(Val, 0, 7) | 0x80;
4081     unsigned rot = fieldFromInstruction(Val, 7, 5);
4082     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
4083     Inst.addOperand(MCOperand::createImm(imm));
4084   }
4085 
4086   return MCDisassembler::Success;
4087 }
4088 
4089 static DecodeStatus
4090 DecodeThumbBCCTargetOperand(MCInst &Inst, unsigned Val,
4091                             uint64_t Address, const void *Decoder) {
4092   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<9>(Val<<1) + 4,
4093                                 true, 2, Inst, Decoder))
4094     Inst.addOperand(MCOperand::createImm(SignExtend32<9>(Val << 1)));
4095   return MCDisassembler::Success;
4096 }
4097 
4098 static DecodeStatus DecodeThumbBLTargetOperand(MCInst &Inst, unsigned Val,
4099                                                uint64_t Address,
4100                                                const void *Decoder) {
4101   // Val is passed in as S:J1:J2:imm10:imm11
4102   // Note no trailing zero after imm11.  Also the J1 and J2 values are from
4103   // the encoded instruction.  So here change to I1 and I2 values via:
4104   // I1 = NOT(J1 EOR S);
4105   // I2 = NOT(J2 EOR S);
4106   // and build the imm32 with one trailing zero as documented:
4107   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
4108   unsigned S = (Val >> 23) & 1;
4109   unsigned J1 = (Val >> 22) & 1;
4110   unsigned J2 = (Val >> 21) & 1;
4111   unsigned I1 = !(J1 ^ S);
4112   unsigned I2 = !(J2 ^ S);
4113   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
4114   int imm32 = SignExtend32<25>(tmp << 1);
4115 
4116   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
4117                                 true, 4, Inst, Decoder))
4118     Inst.addOperand(MCOperand::createImm(imm32));
4119   return MCDisassembler::Success;
4120 }
4121 
4122 static DecodeStatus DecodeMemBarrierOption(MCInst &Inst, unsigned Val,
4123                                    uint64_t Address, const void *Decoder) {
4124   if (Val & ~0xf)
4125     return MCDisassembler::Fail;
4126 
4127   Inst.addOperand(MCOperand::createImm(Val));
4128   return MCDisassembler::Success;
4129 }
4130 
4131 static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Val,
4132                                         uint64_t Address, const void *Decoder) {
4133   if (Val & ~0xf)
4134     return MCDisassembler::Fail;
4135 
4136   Inst.addOperand(MCOperand::createImm(Val));
4137   return MCDisassembler::Success;
4138 }
4139 
4140 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val,
4141                           uint64_t Address, const void *Decoder) {
4142   DecodeStatus S = MCDisassembler::Success;
4143   const FeatureBitset &FeatureBits =
4144     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
4145 
4146   if (FeatureBits[ARM::FeatureMClass]) {
4147     unsigned ValLow = Val & 0xff;
4148 
4149     // Validate the SYSm value first.
4150     switch (ValLow) {
4151     case  0: // apsr
4152     case  1: // iapsr
4153     case  2: // eapsr
4154     case  3: // xpsr
4155     case  5: // ipsr
4156     case  6: // epsr
4157     case  7: // iepsr
4158     case  8: // msp
4159     case  9: // psp
4160     case 16: // primask
4161     case 20: // control
4162       break;
4163     case 17: // basepri
4164     case 18: // basepri_max
4165     case 19: // faultmask
4166       if (!(FeatureBits[ARM::HasV7Ops]))
4167         // Values basepri, basepri_max and faultmask are only valid for v7m.
4168         return MCDisassembler::Fail;
4169       break;
4170     case 0x8a: // msplim_ns
4171     case 0x8b: // psplim_ns
4172     case 0x91: // basepri_ns
4173     case 0x93: // faultmask_ns
4174       if (!(FeatureBits[ARM::HasV8MMainlineOps]))
4175         return MCDisassembler::Fail;
4176       LLVM_FALLTHROUGH;
4177     case 10:   // msplim
4178     case 11:   // psplim
4179     case 0x88: // msp_ns
4180     case 0x89: // psp_ns
4181     case 0x90: // primask_ns
4182     case 0x94: // control_ns
4183     case 0x98: // sp_ns
4184       if (!(FeatureBits[ARM::Feature8MSecExt]))
4185         return MCDisassembler::Fail;
4186       break;
4187     default:
4188       // Architecturally defined as unpredictable
4189       S = MCDisassembler::SoftFail;
4190       break;
4191     }
4192 
4193     if (Inst.getOpcode() == ARM::t2MSR_M) {
4194       unsigned Mask = fieldFromInstruction(Val, 10, 2);
4195       if (!(FeatureBits[ARM::HasV7Ops])) {
4196         // The ARMv6-M MSR bits {11-10} can be only 0b10, other values are
4197         // unpredictable.
4198         if (Mask != 2)
4199           S = MCDisassembler::SoftFail;
4200       }
4201       else {
4202         // The ARMv7-M architecture stores an additional 2-bit mask value in
4203         // MSR bits {11-10}. The mask is used only with apsr, iapsr, eapsr and
4204         // xpsr, it has to be 0b10 in other cases. Bit mask{1} indicates if
4205         // the NZCVQ bits should be moved by the instruction. Bit mask{0}
4206         // indicates the move for the GE{3:0} bits, the mask{0} bit can be set
4207         // only if the processor includes the DSP extension.
4208         if (Mask == 0 || (Mask != 2 && ValLow > 3) ||
4209             (!(FeatureBits[ARM::FeatureDSP]) && (Mask & 1)))
4210           S = MCDisassembler::SoftFail;
4211       }
4212     }
4213   } else {
4214     // A/R class
4215     if (Val == 0)
4216       return MCDisassembler::Fail;
4217   }
4218   Inst.addOperand(MCOperand::createImm(Val));
4219   return S;
4220 }
4221 
4222 static DecodeStatus DecodeBankedReg(MCInst &Inst, unsigned Val,
4223                                     uint64_t Address, const void *Decoder) {
4224   unsigned R = fieldFromInstruction(Val, 5, 1);
4225   unsigned SysM = fieldFromInstruction(Val, 0, 5);
4226 
4227   // The table of encodings for these banked registers comes from B9.2.3 of the
4228   // ARM ARM. There are patterns, but nothing regular enough to make this logic
4229   // neater. So by fiat, these values are UNPREDICTABLE:
4230   if (!ARMBankedReg::lookupBankedRegByEncoding((R << 5) | SysM))
4231     return MCDisassembler::Fail;
4232 
4233   Inst.addOperand(MCOperand::createImm(Val));
4234   return MCDisassembler::Success;
4235 }
4236 
4237 static DecodeStatus DecodeDoubleRegLoad(MCInst &Inst, unsigned Insn,
4238                                         uint64_t Address, const void *Decoder) {
4239   DecodeStatus S = MCDisassembler::Success;
4240 
4241   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4242   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4243   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4244 
4245   if (Rn == 0xF)
4246     S = MCDisassembler::SoftFail;
4247 
4248   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
4249     return MCDisassembler::Fail;
4250   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4251     return MCDisassembler::Fail;
4252   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4253     return MCDisassembler::Fail;
4254 
4255   return S;
4256 }
4257 
4258 static DecodeStatus DecodeDoubleRegStore(MCInst &Inst, unsigned Insn,
4259                                          uint64_t Address,
4260                                          const void *Decoder) {
4261   DecodeStatus S = MCDisassembler::Success;
4262 
4263   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4264   unsigned Rt = fieldFromInstruction(Insn, 0, 4);
4265   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4266   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4267 
4268   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
4269     return MCDisassembler::Fail;
4270 
4271   if (Rn == 0xF || Rd == Rn || Rd == Rt || Rd == Rt+1)
4272     S = MCDisassembler::SoftFail;
4273 
4274   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
4275     return MCDisassembler::Fail;
4276   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4277     return MCDisassembler::Fail;
4278   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4279     return MCDisassembler::Fail;
4280 
4281   return S;
4282 }
4283 
4284 static DecodeStatus DecodeLDRPreImm(MCInst &Inst, unsigned Insn,
4285                             uint64_t Address, const void *Decoder) {
4286   DecodeStatus S = MCDisassembler::Success;
4287 
4288   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4289   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4290   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4291   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4292   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4293   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4294 
4295   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4296 
4297   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4298     return MCDisassembler::Fail;
4299   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4300     return MCDisassembler::Fail;
4301   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
4302     return MCDisassembler::Fail;
4303   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4304     return MCDisassembler::Fail;
4305 
4306   return S;
4307 }
4308 
4309 static DecodeStatus DecodeLDRPreReg(MCInst &Inst, unsigned Insn,
4310                             uint64_t Address, const void *Decoder) {
4311   DecodeStatus S = MCDisassembler::Success;
4312 
4313   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4314   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4315   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4316   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4317   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4318   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4319   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4320 
4321   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4322   if (Rm == 0xF) S = MCDisassembler::SoftFail;
4323 
4324   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4325     return MCDisassembler::Fail;
4326   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4327     return MCDisassembler::Fail;
4328   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
4329     return MCDisassembler::Fail;
4330   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4331     return MCDisassembler::Fail;
4332 
4333   return S;
4334 }
4335 
4336 static DecodeStatus DecodeSTRPreImm(MCInst &Inst, unsigned Insn,
4337                             uint64_t Address, const void *Decoder) {
4338   DecodeStatus S = MCDisassembler::Success;
4339 
4340   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4341   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4342   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4343   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4344   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4345   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4346 
4347   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4348 
4349   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4350     return MCDisassembler::Fail;
4351   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4352     return MCDisassembler::Fail;
4353   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
4354     return MCDisassembler::Fail;
4355   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4356     return MCDisassembler::Fail;
4357 
4358   return S;
4359 }
4360 
4361 static DecodeStatus DecodeSTRPreReg(MCInst &Inst, unsigned Insn,
4362                             uint64_t Address, const void *Decoder) {
4363   DecodeStatus S = MCDisassembler::Success;
4364 
4365   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4366   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
4367   unsigned imm = fieldFromInstruction(Insn, 0, 12);
4368   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
4369   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
4370   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4371 
4372   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
4373 
4374   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4375     return MCDisassembler::Fail;
4376   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
4377     return MCDisassembler::Fail;
4378   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
4379     return MCDisassembler::Fail;
4380   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4381     return MCDisassembler::Fail;
4382 
4383   return S;
4384 }
4385 
4386 static DecodeStatus DecodeVLD1LN(MCInst &Inst, unsigned Insn,
4387                          uint64_t Address, const void *Decoder) {
4388   DecodeStatus S = MCDisassembler::Success;
4389 
4390   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4391   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4392   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4393   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4394   unsigned size = fieldFromInstruction(Insn, 10, 2);
4395 
4396   unsigned align = 0;
4397   unsigned index = 0;
4398   switch (size) {
4399     default:
4400       return MCDisassembler::Fail;
4401     case 0:
4402       if (fieldFromInstruction(Insn, 4, 1))
4403         return MCDisassembler::Fail; // UNDEFINED
4404       index = fieldFromInstruction(Insn, 5, 3);
4405       break;
4406     case 1:
4407       if (fieldFromInstruction(Insn, 5, 1))
4408         return MCDisassembler::Fail; // UNDEFINED
4409       index = fieldFromInstruction(Insn, 6, 2);
4410       if (fieldFromInstruction(Insn, 4, 1))
4411         align = 2;
4412       break;
4413     case 2:
4414       if (fieldFromInstruction(Insn, 6, 1))
4415         return MCDisassembler::Fail; // UNDEFINED
4416       index = fieldFromInstruction(Insn, 7, 1);
4417 
4418       switch (fieldFromInstruction(Insn, 4, 2)) {
4419         case 0 :
4420           align = 0; break;
4421         case 3:
4422           align = 4; break;
4423         default:
4424           return MCDisassembler::Fail;
4425       }
4426       break;
4427   }
4428 
4429   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4430     return MCDisassembler::Fail;
4431   if (Rm != 0xF) { // Writeback
4432     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4433       return MCDisassembler::Fail;
4434   }
4435   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4436     return MCDisassembler::Fail;
4437   Inst.addOperand(MCOperand::createImm(align));
4438   if (Rm != 0xF) {
4439     if (Rm != 0xD) {
4440       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4441         return MCDisassembler::Fail;
4442     } else
4443       Inst.addOperand(MCOperand::createReg(0));
4444   }
4445 
4446   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4447     return MCDisassembler::Fail;
4448   Inst.addOperand(MCOperand::createImm(index));
4449 
4450   return S;
4451 }
4452 
4453 static DecodeStatus DecodeVST1LN(MCInst &Inst, unsigned Insn,
4454                          uint64_t Address, const void *Decoder) {
4455   DecodeStatus S = MCDisassembler::Success;
4456 
4457   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4458   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4459   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4460   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4461   unsigned size = fieldFromInstruction(Insn, 10, 2);
4462 
4463   unsigned align = 0;
4464   unsigned index = 0;
4465   switch (size) {
4466     default:
4467       return MCDisassembler::Fail;
4468     case 0:
4469       if (fieldFromInstruction(Insn, 4, 1))
4470         return MCDisassembler::Fail; // UNDEFINED
4471       index = fieldFromInstruction(Insn, 5, 3);
4472       break;
4473     case 1:
4474       if (fieldFromInstruction(Insn, 5, 1))
4475         return MCDisassembler::Fail; // UNDEFINED
4476       index = fieldFromInstruction(Insn, 6, 2);
4477       if (fieldFromInstruction(Insn, 4, 1))
4478         align = 2;
4479       break;
4480     case 2:
4481       if (fieldFromInstruction(Insn, 6, 1))
4482         return MCDisassembler::Fail; // UNDEFINED
4483       index = fieldFromInstruction(Insn, 7, 1);
4484 
4485       switch (fieldFromInstruction(Insn, 4, 2)) {
4486         case 0:
4487           align = 0; break;
4488         case 3:
4489           align = 4; break;
4490         default:
4491           return MCDisassembler::Fail;
4492       }
4493       break;
4494   }
4495 
4496   if (Rm != 0xF) { // Writeback
4497     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4498     return MCDisassembler::Fail;
4499   }
4500   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4501     return MCDisassembler::Fail;
4502   Inst.addOperand(MCOperand::createImm(align));
4503   if (Rm != 0xF) {
4504     if (Rm != 0xD) {
4505       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4506     return MCDisassembler::Fail;
4507     } else
4508       Inst.addOperand(MCOperand::createReg(0));
4509   }
4510 
4511   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4512     return MCDisassembler::Fail;
4513   Inst.addOperand(MCOperand::createImm(index));
4514 
4515   return S;
4516 }
4517 
4518 static DecodeStatus DecodeVLD2LN(MCInst &Inst, unsigned Insn,
4519                          uint64_t Address, const void *Decoder) {
4520   DecodeStatus S = MCDisassembler::Success;
4521 
4522   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4523   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4524   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4525   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4526   unsigned size = fieldFromInstruction(Insn, 10, 2);
4527 
4528   unsigned align = 0;
4529   unsigned index = 0;
4530   unsigned inc = 1;
4531   switch (size) {
4532     default:
4533       return MCDisassembler::Fail;
4534     case 0:
4535       index = fieldFromInstruction(Insn, 5, 3);
4536       if (fieldFromInstruction(Insn, 4, 1))
4537         align = 2;
4538       break;
4539     case 1:
4540       index = fieldFromInstruction(Insn, 6, 2);
4541       if (fieldFromInstruction(Insn, 4, 1))
4542         align = 4;
4543       if (fieldFromInstruction(Insn, 5, 1))
4544         inc = 2;
4545       break;
4546     case 2:
4547       if (fieldFromInstruction(Insn, 5, 1))
4548         return MCDisassembler::Fail; // UNDEFINED
4549       index = fieldFromInstruction(Insn, 7, 1);
4550       if (fieldFromInstruction(Insn, 4, 1) != 0)
4551         align = 8;
4552       if (fieldFromInstruction(Insn, 6, 1))
4553         inc = 2;
4554       break;
4555   }
4556 
4557   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4558     return MCDisassembler::Fail;
4559   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4560     return MCDisassembler::Fail;
4561   if (Rm != 0xF) { // Writeback
4562     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4563       return MCDisassembler::Fail;
4564   }
4565   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4566     return MCDisassembler::Fail;
4567   Inst.addOperand(MCOperand::createImm(align));
4568   if (Rm != 0xF) {
4569     if (Rm != 0xD) {
4570       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4571         return MCDisassembler::Fail;
4572     } else
4573       Inst.addOperand(MCOperand::createReg(0));
4574   }
4575 
4576   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4577     return MCDisassembler::Fail;
4578   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4579     return MCDisassembler::Fail;
4580   Inst.addOperand(MCOperand::createImm(index));
4581 
4582   return S;
4583 }
4584 
4585 static DecodeStatus DecodeVST2LN(MCInst &Inst, unsigned Insn,
4586                          uint64_t Address, const void *Decoder) {
4587   DecodeStatus S = MCDisassembler::Success;
4588 
4589   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4590   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4591   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4592   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4593   unsigned size = fieldFromInstruction(Insn, 10, 2);
4594 
4595   unsigned align = 0;
4596   unsigned index = 0;
4597   unsigned inc = 1;
4598   switch (size) {
4599     default:
4600       return MCDisassembler::Fail;
4601     case 0:
4602       index = fieldFromInstruction(Insn, 5, 3);
4603       if (fieldFromInstruction(Insn, 4, 1))
4604         align = 2;
4605       break;
4606     case 1:
4607       index = fieldFromInstruction(Insn, 6, 2);
4608       if (fieldFromInstruction(Insn, 4, 1))
4609         align = 4;
4610       if (fieldFromInstruction(Insn, 5, 1))
4611         inc = 2;
4612       break;
4613     case 2:
4614       if (fieldFromInstruction(Insn, 5, 1))
4615         return MCDisassembler::Fail; // UNDEFINED
4616       index = fieldFromInstruction(Insn, 7, 1);
4617       if (fieldFromInstruction(Insn, 4, 1) != 0)
4618         align = 8;
4619       if (fieldFromInstruction(Insn, 6, 1))
4620         inc = 2;
4621       break;
4622   }
4623 
4624   if (Rm != 0xF) { // Writeback
4625     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4626       return MCDisassembler::Fail;
4627   }
4628   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4629     return MCDisassembler::Fail;
4630   Inst.addOperand(MCOperand::createImm(align));
4631   if (Rm != 0xF) {
4632     if (Rm != 0xD) {
4633       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4634         return MCDisassembler::Fail;
4635     } else
4636       Inst.addOperand(MCOperand::createReg(0));
4637   }
4638 
4639   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4640     return MCDisassembler::Fail;
4641   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4642     return MCDisassembler::Fail;
4643   Inst.addOperand(MCOperand::createImm(index));
4644 
4645   return S;
4646 }
4647 
4648 static DecodeStatus DecodeVLD3LN(MCInst &Inst, unsigned Insn,
4649                          uint64_t Address, const void *Decoder) {
4650   DecodeStatus S = MCDisassembler::Success;
4651 
4652   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4653   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4654   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4655   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4656   unsigned size = fieldFromInstruction(Insn, 10, 2);
4657 
4658   unsigned align = 0;
4659   unsigned index = 0;
4660   unsigned inc = 1;
4661   switch (size) {
4662     default:
4663       return MCDisassembler::Fail;
4664     case 0:
4665       if (fieldFromInstruction(Insn, 4, 1))
4666         return MCDisassembler::Fail; // UNDEFINED
4667       index = fieldFromInstruction(Insn, 5, 3);
4668       break;
4669     case 1:
4670       if (fieldFromInstruction(Insn, 4, 1))
4671         return MCDisassembler::Fail; // UNDEFINED
4672       index = fieldFromInstruction(Insn, 6, 2);
4673       if (fieldFromInstruction(Insn, 5, 1))
4674         inc = 2;
4675       break;
4676     case 2:
4677       if (fieldFromInstruction(Insn, 4, 2))
4678         return MCDisassembler::Fail; // UNDEFINED
4679       index = fieldFromInstruction(Insn, 7, 1);
4680       if (fieldFromInstruction(Insn, 6, 1))
4681         inc = 2;
4682       break;
4683   }
4684 
4685   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4686     return MCDisassembler::Fail;
4687   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4688     return MCDisassembler::Fail;
4689   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4690     return MCDisassembler::Fail;
4691 
4692   if (Rm != 0xF) { // Writeback
4693     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4694     return MCDisassembler::Fail;
4695   }
4696   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4697     return MCDisassembler::Fail;
4698   Inst.addOperand(MCOperand::createImm(align));
4699   if (Rm != 0xF) {
4700     if (Rm != 0xD) {
4701       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4702     return MCDisassembler::Fail;
4703     } else
4704       Inst.addOperand(MCOperand::createReg(0));
4705   }
4706 
4707   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4708     return MCDisassembler::Fail;
4709   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4710     return MCDisassembler::Fail;
4711   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4712     return MCDisassembler::Fail;
4713   Inst.addOperand(MCOperand::createImm(index));
4714 
4715   return S;
4716 }
4717 
4718 static DecodeStatus DecodeVST3LN(MCInst &Inst, unsigned Insn,
4719                          uint64_t Address, const void *Decoder) {
4720   DecodeStatus S = MCDisassembler::Success;
4721 
4722   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4723   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4724   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4725   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4726   unsigned size = fieldFromInstruction(Insn, 10, 2);
4727 
4728   unsigned align = 0;
4729   unsigned index = 0;
4730   unsigned inc = 1;
4731   switch (size) {
4732     default:
4733       return MCDisassembler::Fail;
4734     case 0:
4735       if (fieldFromInstruction(Insn, 4, 1))
4736         return MCDisassembler::Fail; // UNDEFINED
4737       index = fieldFromInstruction(Insn, 5, 3);
4738       break;
4739     case 1:
4740       if (fieldFromInstruction(Insn, 4, 1))
4741         return MCDisassembler::Fail; // UNDEFINED
4742       index = fieldFromInstruction(Insn, 6, 2);
4743       if (fieldFromInstruction(Insn, 5, 1))
4744         inc = 2;
4745       break;
4746     case 2:
4747       if (fieldFromInstruction(Insn, 4, 2))
4748         return MCDisassembler::Fail; // UNDEFINED
4749       index = fieldFromInstruction(Insn, 7, 1);
4750       if (fieldFromInstruction(Insn, 6, 1))
4751         inc = 2;
4752       break;
4753   }
4754 
4755   if (Rm != 0xF) { // Writeback
4756     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4757     return MCDisassembler::Fail;
4758   }
4759   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4760     return MCDisassembler::Fail;
4761   Inst.addOperand(MCOperand::createImm(align));
4762   if (Rm != 0xF) {
4763     if (Rm != 0xD) {
4764       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4765     return MCDisassembler::Fail;
4766     } else
4767       Inst.addOperand(MCOperand::createReg(0));
4768   }
4769 
4770   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4771     return MCDisassembler::Fail;
4772   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4773     return MCDisassembler::Fail;
4774   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4775     return MCDisassembler::Fail;
4776   Inst.addOperand(MCOperand::createImm(index));
4777 
4778   return S;
4779 }
4780 
4781 static DecodeStatus DecodeVLD4LN(MCInst &Inst, unsigned Insn,
4782                          uint64_t Address, const void *Decoder) {
4783   DecodeStatus S = MCDisassembler::Success;
4784 
4785   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4786   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4787   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4788   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4789   unsigned size = fieldFromInstruction(Insn, 10, 2);
4790 
4791   unsigned align = 0;
4792   unsigned index = 0;
4793   unsigned inc = 1;
4794   switch (size) {
4795     default:
4796       return MCDisassembler::Fail;
4797     case 0:
4798       if (fieldFromInstruction(Insn, 4, 1))
4799         align = 4;
4800       index = fieldFromInstruction(Insn, 5, 3);
4801       break;
4802     case 1:
4803       if (fieldFromInstruction(Insn, 4, 1))
4804         align = 8;
4805       index = fieldFromInstruction(Insn, 6, 2);
4806       if (fieldFromInstruction(Insn, 5, 1))
4807         inc = 2;
4808       break;
4809     case 2:
4810       switch (fieldFromInstruction(Insn, 4, 2)) {
4811         case 0:
4812           align = 0; break;
4813         case 3:
4814           return MCDisassembler::Fail;
4815         default:
4816           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
4817       }
4818 
4819       index = fieldFromInstruction(Insn, 7, 1);
4820       if (fieldFromInstruction(Insn, 6, 1))
4821         inc = 2;
4822       break;
4823   }
4824 
4825   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4826     return MCDisassembler::Fail;
4827   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4828     return MCDisassembler::Fail;
4829   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4830     return MCDisassembler::Fail;
4831   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
4832     return MCDisassembler::Fail;
4833 
4834   if (Rm != 0xF) { // Writeback
4835     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4836       return MCDisassembler::Fail;
4837   }
4838   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4839     return MCDisassembler::Fail;
4840   Inst.addOperand(MCOperand::createImm(align));
4841   if (Rm != 0xF) {
4842     if (Rm != 0xD) {
4843       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4844         return MCDisassembler::Fail;
4845     } else
4846       Inst.addOperand(MCOperand::createReg(0));
4847   }
4848 
4849   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4850     return MCDisassembler::Fail;
4851   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4852     return MCDisassembler::Fail;
4853   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4854     return MCDisassembler::Fail;
4855   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
4856     return MCDisassembler::Fail;
4857   Inst.addOperand(MCOperand::createImm(index));
4858 
4859   return S;
4860 }
4861 
4862 static DecodeStatus DecodeVST4LN(MCInst &Inst, unsigned Insn,
4863                          uint64_t Address, const void *Decoder) {
4864   DecodeStatus S = MCDisassembler::Success;
4865 
4866   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
4867   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
4868   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
4869   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
4870   unsigned size = fieldFromInstruction(Insn, 10, 2);
4871 
4872   unsigned align = 0;
4873   unsigned index = 0;
4874   unsigned inc = 1;
4875   switch (size) {
4876     default:
4877       return MCDisassembler::Fail;
4878     case 0:
4879       if (fieldFromInstruction(Insn, 4, 1))
4880         align = 4;
4881       index = fieldFromInstruction(Insn, 5, 3);
4882       break;
4883     case 1:
4884       if (fieldFromInstruction(Insn, 4, 1))
4885         align = 8;
4886       index = fieldFromInstruction(Insn, 6, 2);
4887       if (fieldFromInstruction(Insn, 5, 1))
4888         inc = 2;
4889       break;
4890     case 2:
4891       switch (fieldFromInstruction(Insn, 4, 2)) {
4892         case 0:
4893           align = 0; break;
4894         case 3:
4895           return MCDisassembler::Fail;
4896         default:
4897           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
4898       }
4899 
4900       index = fieldFromInstruction(Insn, 7, 1);
4901       if (fieldFromInstruction(Insn, 6, 1))
4902         inc = 2;
4903       break;
4904   }
4905 
4906   if (Rm != 0xF) { // Writeback
4907     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4908     return MCDisassembler::Fail;
4909   }
4910   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
4911     return MCDisassembler::Fail;
4912   Inst.addOperand(MCOperand::createImm(align));
4913   if (Rm != 0xF) {
4914     if (Rm != 0xD) {
4915       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
4916     return MCDisassembler::Fail;
4917     } else
4918       Inst.addOperand(MCOperand::createReg(0));
4919   }
4920 
4921   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
4922     return MCDisassembler::Fail;
4923   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
4924     return MCDisassembler::Fail;
4925   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
4926     return MCDisassembler::Fail;
4927   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
4928     return MCDisassembler::Fail;
4929   Inst.addOperand(MCOperand::createImm(index));
4930 
4931   return S;
4932 }
4933 
4934 static DecodeStatus DecodeVMOVSRR(MCInst &Inst, unsigned Insn,
4935                                   uint64_t Address, const void *Decoder) {
4936   DecodeStatus S = MCDisassembler::Success;
4937   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
4938   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
4939   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
4940   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4941   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
4942 
4943   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
4944     S = MCDisassembler::SoftFail;
4945 
4946   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
4947     return MCDisassembler::Fail;
4948   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
4949     return MCDisassembler::Fail;
4950   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
4951     return MCDisassembler::Fail;
4952   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
4953     return MCDisassembler::Fail;
4954   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4955     return MCDisassembler::Fail;
4956 
4957   return S;
4958 }
4959 
4960 static DecodeStatus DecodeVMOVRRS(MCInst &Inst, unsigned Insn,
4961                                   uint64_t Address, const void *Decoder) {
4962   DecodeStatus S = MCDisassembler::Success;
4963   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
4964   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
4965   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
4966   unsigned pred = fieldFromInstruction(Insn, 28, 4);
4967   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
4968 
4969   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
4970     S = MCDisassembler::SoftFail;
4971 
4972   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
4973     return MCDisassembler::Fail;
4974   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
4975     return MCDisassembler::Fail;
4976   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
4977     return MCDisassembler::Fail;
4978   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
4979     return MCDisassembler::Fail;
4980   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
4981     return MCDisassembler::Fail;
4982 
4983   return S;
4984 }
4985 
4986 static DecodeStatus DecodeIT(MCInst &Inst, unsigned Insn,
4987                              uint64_t Address, const void *Decoder) {
4988   DecodeStatus S = MCDisassembler::Success;
4989   unsigned pred = fieldFromInstruction(Insn, 4, 4);
4990   unsigned mask = fieldFromInstruction(Insn, 0, 4);
4991 
4992   if (pred == 0xF) {
4993     pred = 0xE;
4994     S = MCDisassembler::SoftFail;
4995   }
4996 
4997   if (mask == 0x0)
4998     return MCDisassembler::Fail;
4999 
5000   Inst.addOperand(MCOperand::createImm(pred));
5001   Inst.addOperand(MCOperand::createImm(mask));
5002   return S;
5003 }
5004 
5005 static DecodeStatus
5006 DecodeT2LDRDPreInstruction(MCInst &Inst, unsigned Insn,
5007                            uint64_t Address, const void *Decoder) {
5008   DecodeStatus S = MCDisassembler::Success;
5009 
5010   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
5011   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
5012   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5013   unsigned addr = fieldFromInstruction(Insn, 0, 8);
5014   unsigned W = fieldFromInstruction(Insn, 21, 1);
5015   unsigned U = fieldFromInstruction(Insn, 23, 1);
5016   unsigned P = fieldFromInstruction(Insn, 24, 1);
5017   bool writeback = (W == 1) | (P == 0);
5018 
5019   addr |= (U << 8) | (Rn << 9);
5020 
5021   if (writeback && (Rn == Rt || Rn == Rt2))
5022     Check(S, MCDisassembler::SoftFail);
5023   if (Rt == Rt2)
5024     Check(S, MCDisassembler::SoftFail);
5025 
5026   // Rt
5027   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
5028     return MCDisassembler::Fail;
5029   // Rt2
5030   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
5031     return MCDisassembler::Fail;
5032   // Writeback operand
5033   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
5034     return MCDisassembler::Fail;
5035   // addr
5036   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
5037     return MCDisassembler::Fail;
5038 
5039   return S;
5040 }
5041 
5042 static DecodeStatus
5043 DecodeT2STRDPreInstruction(MCInst &Inst, unsigned Insn,
5044                            uint64_t Address, const void *Decoder) {
5045   DecodeStatus S = MCDisassembler::Success;
5046 
5047   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
5048   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
5049   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
5050   unsigned addr = fieldFromInstruction(Insn, 0, 8);
5051   unsigned W = fieldFromInstruction(Insn, 21, 1);
5052   unsigned U = fieldFromInstruction(Insn, 23, 1);
5053   unsigned P = fieldFromInstruction(Insn, 24, 1);
5054   bool writeback = (W == 1) | (P == 0);
5055 
5056   addr |= (U << 8) | (Rn << 9);
5057 
5058   if (writeback && (Rn == Rt || Rn == Rt2))
5059     Check(S, MCDisassembler::SoftFail);
5060 
5061   // Writeback operand
5062   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
5063     return MCDisassembler::Fail;
5064   // Rt
5065   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
5066     return MCDisassembler::Fail;
5067   // Rt2
5068   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
5069     return MCDisassembler::Fail;
5070   // addr
5071   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
5072     return MCDisassembler::Fail;
5073 
5074   return S;
5075 }
5076 
5077 static DecodeStatus DecodeT2Adr(MCInst &Inst, uint32_t Insn,
5078                                 uint64_t Address, const void *Decoder) {
5079   unsigned sign1 = fieldFromInstruction(Insn, 21, 1);
5080   unsigned sign2 = fieldFromInstruction(Insn, 23, 1);
5081   if (sign1 != sign2) return MCDisassembler::Fail;
5082 
5083   unsigned Val = fieldFromInstruction(Insn, 0, 8);
5084   Val |= fieldFromInstruction(Insn, 12, 3) << 8;
5085   Val |= fieldFromInstruction(Insn, 26, 1) << 11;
5086   Val |= sign1 << 12;
5087   Inst.addOperand(MCOperand::createImm(SignExtend32<13>(Val)));
5088 
5089   return MCDisassembler::Success;
5090 }
5091 
5092 static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, uint32_t Val,
5093                                               uint64_t Address,
5094                                               const void *Decoder) {
5095   DecodeStatus S = MCDisassembler::Success;
5096 
5097   // Shift of "asr #32" is not allowed in Thumb2 mode.
5098   if (Val == 0x20) S = MCDisassembler::Fail;
5099   Inst.addOperand(MCOperand::createImm(Val));
5100   return S;
5101 }
5102 
5103 static DecodeStatus DecodeSwap(MCInst &Inst, unsigned Insn,
5104                                uint64_t Address, const void *Decoder) {
5105   unsigned Rt   = fieldFromInstruction(Insn, 12, 4);
5106   unsigned Rt2  = fieldFromInstruction(Insn, 0,  4);
5107   unsigned Rn   = fieldFromInstruction(Insn, 16, 4);
5108   unsigned pred = fieldFromInstruction(Insn, 28, 4);
5109 
5110   if (pred == 0xF)
5111     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
5112 
5113   DecodeStatus S = MCDisassembler::Success;
5114 
5115   if (Rt == Rn || Rn == Rt2)
5116     S = MCDisassembler::SoftFail;
5117 
5118   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5119     return MCDisassembler::Fail;
5120   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5121     return MCDisassembler::Fail;
5122   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
5123     return MCDisassembler::Fail;
5124   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5125     return MCDisassembler::Fail;
5126 
5127   return S;
5128 }
5129 
5130 static DecodeStatus DecodeVCVTD(MCInst &Inst, unsigned Insn,
5131                                 uint64_t Address, const void *Decoder) {
5132   const FeatureBitset &featureBits =
5133       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5134   bool hasFullFP16 = featureBits[ARM::FeatureFullFP16];
5135 
5136   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5137   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5138   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5139   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5140   unsigned imm = fieldFromInstruction(Insn, 16, 6);
5141   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
5142   unsigned op = fieldFromInstruction(Insn, 5, 1);
5143 
5144   DecodeStatus S = MCDisassembler::Success;
5145 
5146   // If the top 3 bits of imm are clear, this is a VMOV (immediate)
5147   if (!(imm & 0x38)) {
5148     if (cmode == 0xF) {
5149       if (op == 1) return MCDisassembler::Fail;
5150       Inst.setOpcode(ARM::VMOVv2f32);
5151     }
5152     if (hasFullFP16) {
5153       if (cmode == 0xE) {
5154         if (op == 1) {
5155           Inst.setOpcode(ARM::VMOVv1i64);
5156         } else {
5157           Inst.setOpcode(ARM::VMOVv8i8);
5158         }
5159       }
5160       if (cmode == 0xD) {
5161         if (op == 1) {
5162           Inst.setOpcode(ARM::VMVNv2i32);
5163         } else {
5164           Inst.setOpcode(ARM::VMOVv2i32);
5165         }
5166       }
5167       if (cmode == 0xC) {
5168         if (op == 1) {
5169           Inst.setOpcode(ARM::VMVNv2i32);
5170         } else {
5171           Inst.setOpcode(ARM::VMOVv2i32);
5172         }
5173       }
5174     }
5175     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
5176   }
5177 
5178   if (!(imm & 0x20)) return MCDisassembler::Fail;
5179 
5180   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
5181     return MCDisassembler::Fail;
5182   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
5183     return MCDisassembler::Fail;
5184   Inst.addOperand(MCOperand::createImm(64 - imm));
5185 
5186   return S;
5187 }
5188 
5189 static DecodeStatus DecodeVCVTQ(MCInst &Inst, unsigned Insn,
5190                                 uint64_t Address, const void *Decoder) {
5191   const FeatureBitset &featureBits =
5192       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5193   bool hasFullFP16 = featureBits[ARM::FeatureFullFP16];
5194 
5195   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5196   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5197   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5198   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5199   unsigned imm = fieldFromInstruction(Insn, 16, 6);
5200   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
5201   unsigned op = fieldFromInstruction(Insn, 5, 1);
5202 
5203   DecodeStatus S = MCDisassembler::Success;
5204 
5205   // If the top 3 bits of imm are clear, this is a VMOV (immediate)
5206   if (!(imm & 0x38)) {
5207     if (cmode == 0xF) {
5208       if (op == 1) return MCDisassembler::Fail;
5209       Inst.setOpcode(ARM::VMOVv4f32);
5210     }
5211     if (hasFullFP16) {
5212       if (cmode == 0xE) {
5213         if (op == 1) {
5214           Inst.setOpcode(ARM::VMOVv2i64);
5215         } else {
5216           Inst.setOpcode(ARM::VMOVv16i8);
5217         }
5218       }
5219       if (cmode == 0xD) {
5220         if (op == 1) {
5221           Inst.setOpcode(ARM::VMVNv4i32);
5222         } else {
5223           Inst.setOpcode(ARM::VMOVv4i32);
5224         }
5225       }
5226       if (cmode == 0xC) {
5227         if (op == 1) {
5228           Inst.setOpcode(ARM::VMVNv4i32);
5229         } else {
5230           Inst.setOpcode(ARM::VMOVv4i32);
5231         }
5232       }
5233     }
5234     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
5235   }
5236 
5237   if (!(imm & 0x20)) return MCDisassembler::Fail;
5238 
5239   if (!Check(S, DecodeQPRRegisterClass(Inst, Vd, Address, Decoder)))
5240     return MCDisassembler::Fail;
5241   if (!Check(S, DecodeQPRRegisterClass(Inst, Vm, Address, Decoder)))
5242     return MCDisassembler::Fail;
5243   Inst.addOperand(MCOperand::createImm(64 - imm));
5244 
5245   return S;
5246 }
5247 
5248 static DecodeStatus DecodeNEONComplexLane64Instruction(MCInst &Inst,
5249                                                        unsigned Insn,
5250                                                        uint64_t Address,
5251                                                        const void *Decoder) {
5252   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
5253   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
5254   unsigned Vn = (fieldFromInstruction(Insn, 16, 4) << 0);
5255   Vn |= (fieldFromInstruction(Insn, 7, 1) << 4);
5256   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
5257   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
5258   unsigned q = (fieldFromInstruction(Insn, 6, 1) << 0);
5259   unsigned rotate = (fieldFromInstruction(Insn, 20, 2) << 0);
5260 
5261   DecodeStatus S = MCDisassembler::Success;
5262 
5263   auto DestRegDecoder = q ? DecodeQPRRegisterClass : DecodeDPRRegisterClass;
5264 
5265   if (!Check(S, DestRegDecoder(Inst, Vd, Address, Decoder)))
5266     return MCDisassembler::Fail;
5267   if (!Check(S, DestRegDecoder(Inst, Vd, Address, Decoder)))
5268     return MCDisassembler::Fail;
5269   if (!Check(S, DestRegDecoder(Inst, Vn, Address, Decoder)))
5270     return MCDisassembler::Fail;
5271   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
5272     return MCDisassembler::Fail;
5273   // The lane index does not have any bits in the encoding, because it can only
5274   // be 0.
5275   Inst.addOperand(MCOperand::createImm(0));
5276   Inst.addOperand(MCOperand::createImm(rotate));
5277 
5278   return S;
5279 }
5280 
5281 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
5282                                 uint64_t Address, const void *Decoder) {
5283   DecodeStatus S = MCDisassembler::Success;
5284 
5285   unsigned Rn = fieldFromInstruction(Val, 16, 4);
5286   unsigned Rt = fieldFromInstruction(Val, 12, 4);
5287   unsigned Rm = fieldFromInstruction(Val, 0, 4);
5288   Rm |= (fieldFromInstruction(Val, 23, 1) << 4);
5289   unsigned Cond = fieldFromInstruction(Val, 28, 4);
5290 
5291   if (fieldFromInstruction(Val, 8, 4) != 0 || Rn == Rt)
5292     S = MCDisassembler::SoftFail;
5293 
5294   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5295     return MCDisassembler::Fail;
5296   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
5297     return MCDisassembler::Fail;
5298   if (!Check(S, DecodeAddrMode7Operand(Inst, Rn, Address, Decoder)))
5299     return MCDisassembler::Fail;
5300   if (!Check(S, DecodePostIdxReg(Inst, Rm, Address, Decoder)))
5301     return MCDisassembler::Fail;
5302   if (!Check(S, DecodePredicateOperand(Inst, Cond, Address, Decoder)))
5303     return MCDisassembler::Fail;
5304 
5305   return S;
5306 }
5307 
5308 static DecodeStatus DecoderForMRRC2AndMCRR2(MCInst &Inst, unsigned Val,
5309                                             uint64_t Address, const void *Decoder) {
5310   DecodeStatus S = MCDisassembler::Success;
5311 
5312   unsigned CRm = fieldFromInstruction(Val, 0, 4);
5313   unsigned opc1 = fieldFromInstruction(Val, 4, 4);
5314   unsigned cop = fieldFromInstruction(Val, 8, 4);
5315   unsigned Rt = fieldFromInstruction(Val, 12, 4);
5316   unsigned Rt2 = fieldFromInstruction(Val, 16, 4);
5317 
5318   if ((cop & ~0x1) == 0xa)
5319     return MCDisassembler::Fail;
5320 
5321   if (Rt == Rt2)
5322     S = MCDisassembler::SoftFail;
5323 
5324   // We have to check if the instruction is MRRC2
5325   // or MCRR2 when constructing the operands for
5326   // Inst. Reason is because MRRC2 stores to two
5327   // registers so it's tablegen desc has has two
5328   // outputs whereas MCRR doesn't store to any
5329   // registers so all of it's operands are listed
5330   // as inputs, therefore the operand order for
5331   // MRRC2 needs to be [Rt, Rt2, cop, opc1, CRm]
5332   // and MCRR2 operand order is [cop, opc1, Rt, Rt2, CRm]
5333 
5334   if (Inst.getOpcode() == ARM::MRRC2) {
5335     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5336       return MCDisassembler::Fail;
5337     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5338       return MCDisassembler::Fail;
5339   }
5340   Inst.addOperand(MCOperand::createImm(cop));
5341   Inst.addOperand(MCOperand::createImm(opc1));
5342   if (Inst.getOpcode() == ARM::MCRR2) {
5343     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
5344       return MCDisassembler::Fail;
5345     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
5346       return MCDisassembler::Fail;
5347   }
5348   Inst.addOperand(MCOperand::createImm(CRm));
5349 
5350   return S;
5351 }
5352 
5353 static DecodeStatus DecodeForVMRSandVMSR(MCInst &Inst, unsigned Val,
5354                                          uint64_t Address,
5355                                          const void *Decoder) {
5356   const FeatureBitset &featureBits =
5357       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
5358   DecodeStatus S = MCDisassembler::Success;
5359 
5360   unsigned Rt = fieldFromInstruction(Val, 12, 4);
5361 
5362   if (featureBits[ARM::ModeThumb] && !featureBits[ARM::HasV8Ops]) {
5363     if (Rt == 13 || Rt == 15)
5364       S = MCDisassembler::SoftFail;
5365     Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
5366   } else
5367     Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder));
5368 
5369   if (featureBits[ARM::ModeThumb]) {
5370     Inst.addOperand(MCOperand::createImm(ARMCC::AL));
5371     Inst.addOperand(MCOperand::createReg(0));
5372   } else {
5373     unsigned pred = fieldFromInstruction(Val, 28, 4);
5374     if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
5375       return MCDisassembler::Fail;
5376   }
5377 
5378   return S;
5379 }
5380