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      1 //===- ARMDisassembler.cpp - Disassembler for ARM/Thumb ISA ---------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 #include "MCTargetDesc/ARMAddressingModes.h"
     11 #include "MCTargetDesc/ARMBaseInfo.h"
     12 #include "MCTargetDesc/ARMMCTargetDesc.h"
     13 #include "Utils/ARMBaseInfo.h"
     14 #include "llvm/MC/MCContext.h"
     15 #include "llvm/MC/MCDisassembler/MCDisassembler.h"
     16 #include "llvm/MC/MCFixedLenDisassembler.h"
     17 #include "llvm/MC/MCInst.h"
     18 #include "llvm/MC/MCInstrDesc.h"
     19 #include "llvm/MC/MCSubtargetInfo.h"
     20 #include "llvm/MC/SubtargetFeature.h"
     21 #include "llvm/Support/Compiler.h"
     22 #include "llvm/Support/ErrorHandling.h"
     23 #include "llvm/Support/MathExtras.h"
     24 #include "llvm/Support/TargetRegistry.h"
     25 #include "llvm/Support/raw_ostream.h"
     26 #include <algorithm>
     27 #include <cassert>
     28 #include <cstdint>
     29 #include <vector>
     30 
     31 using namespace llvm;
     32 
     33 #define DEBUG_TYPE "arm-disassembler"
     34 
     35 using DecodeStatus = MCDisassembler::DecodeStatus;
     36 
     37 namespace {
     38 
     39   // Handles the condition code status of instructions in IT blocks
     40   class ITStatus
     41   {
     42     public:
     43       // Returns the condition code for instruction in IT block
     44       unsigned getITCC() {
     45         unsigned CC = ARMCC::AL;
     46         if (instrInITBlock())
     47           CC = ITStates.back();
     48         return CC;
     49       }
     50 
     51       // Advances the IT block state to the next T or E
     52       void advanceITState() {
     53         ITStates.pop_back();
     54       }
     55 
     56       // Returns true if the current instruction is in an IT block
     57       bool instrInITBlock() {
     58         return !ITStates.empty();
     59       }
     60 
     61       // Returns true if current instruction is the last instruction in an IT block
     62       bool instrLastInITBlock() {
     63         return ITStates.size() == 1;
     64       }
     65 
     66       // Called when decoding an IT instruction. Sets the IT state for the following
     67       // instructions that for the IT block. Firstcond and Mask correspond to the
     68       // fields in the IT instruction encoding.
     69       void setITState(char Firstcond, char Mask) {
     70         // (3 - the number of trailing zeros) is the number of then / else.
     71         unsigned CondBit0 = Firstcond & 1;
     72         unsigned NumTZ = countTrailingZeros<uint8_t>(Mask);
     73         unsigned char CCBits = static_cast<unsigned char>(Firstcond & 0xf);
     74         assert(NumTZ <= 3 && "Invalid IT mask!");
     75         // push condition codes onto the stack the correct order for the pops
     76         for (unsigned Pos = NumTZ+1; Pos <= 3; ++Pos) {
     77           bool T = ((Mask >> Pos) & 1) == CondBit0;
     78           if (T)
     79             ITStates.push_back(CCBits);
     80           else
     81             ITStates.push_back(CCBits ^ 1);
     82         }
     83         ITStates.push_back(CCBits);
     84       }
     85 
     86     private:
     87       std::vector<unsigned char> ITStates;
     88   };
     89 
     90 /// ARM disassembler for all ARM platforms.
     91 class ARMDisassembler : public MCDisassembler {
     92 public:
     93   ARMDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx) :
     94     MCDisassembler(STI, Ctx) {
     95   }
     96 
     97   ~ARMDisassembler() override = default;
     98 
     99   DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
    100                               ArrayRef<uint8_t> Bytes, uint64_t Address,
    101                               raw_ostream &VStream,
    102                               raw_ostream &CStream) const override;
    103 };
    104 
    105 /// Thumb disassembler for all Thumb platforms.
    106 class ThumbDisassembler : public MCDisassembler {
    107 public:
    108   ThumbDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx) :
    109     MCDisassembler(STI, Ctx) {
    110   }
    111 
    112   ~ThumbDisassembler() override = default;
    113 
    114   DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
    115                               ArrayRef<uint8_t> Bytes, uint64_t Address,
    116                               raw_ostream &VStream,
    117                               raw_ostream &CStream) const override;
    118 
    119 private:
    120   mutable ITStatus ITBlock;
    121 
    122   DecodeStatus AddThumbPredicate(MCInst&) const;
    123   void UpdateThumbVFPPredicate(MCInst&) const;
    124 };
    125 
    126 } // end anonymous namespace
    127 
    128 static bool Check(DecodeStatus &Out, DecodeStatus In) {
    129   switch (In) {
    130     case MCDisassembler::Success:
    131       // Out stays the same.
    132       return true;
    133     case MCDisassembler::SoftFail:
    134       Out = In;
    135       return true;
    136     case MCDisassembler::Fail:
    137       Out = In;
    138       return false;
    139   }
    140   llvm_unreachable("Invalid DecodeStatus!");
    141 }
    142 
    143 // Forward declare these because the autogenerated code will reference them.
    144 // Definitions are further down.
    145 static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
    146                                    uint64_t Address, const void *Decoder);
    147 static DecodeStatus DecodeGPRnopcRegisterClass(MCInst &Inst,
    148                                                unsigned RegNo, uint64_t Address,
    149                                                const void *Decoder);
    150 static DecodeStatus DecodeGPRwithAPSRRegisterClass(MCInst &Inst,
    151                                                unsigned RegNo, uint64_t Address,
    152                                                const void *Decoder);
    153 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
    154                                    uint64_t Address, const void *Decoder);
    155 static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
    156                                    uint64_t Address, const void *Decoder);
    157 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
    158                                    uint64_t Address, const void *Decoder);
    159 static DecodeStatus DecodeGPRPairRegisterClass(MCInst &Inst, unsigned RegNo,
    160                                    uint64_t Address, const void *Decoder);
    161 static DecodeStatus DecodeHPRRegisterClass(MCInst &Inst, unsigned RegNo,
    162                                    uint64_t Address, const void *Decoder);
    163 static DecodeStatus DecodeSPRRegisterClass(MCInst &Inst, unsigned RegNo,
    164                                    uint64_t Address, const void *Decoder);
    165 static DecodeStatus DecodeDPRRegisterClass(MCInst &Inst, unsigned RegNo,
    166                                    uint64_t Address, const void *Decoder);
    167 static DecodeStatus DecodeDPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
    168                                    uint64_t Address, const void *Decoder);
    169 static DecodeStatus DecodeDPR_VFP2RegisterClass(MCInst &Inst,
    170                                                 unsigned RegNo,
    171                                                 uint64_t Address,
    172                                                 const void *Decoder);
    173 static DecodeStatus DecodeQPRRegisterClass(MCInst &Inst, unsigned RegNo,
    174                                    uint64_t Address, const void *Decoder);
    175 static DecodeStatus DecodeDPairRegisterClass(MCInst &Inst, unsigned RegNo,
    176                                    uint64_t Address, const void *Decoder);
    177 static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst &Inst,
    178                                unsigned RegNo, uint64_t Address,
    179                                const void *Decoder);
    180 
    181 static DecodeStatus DecodePredicateOperand(MCInst &Inst, unsigned Val,
    182                                uint64_t Address, const void *Decoder);
    183 static DecodeStatus DecodeCCOutOperand(MCInst &Inst, unsigned Val,
    184                                uint64_t Address, const void *Decoder);
    185 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
    186                                uint64_t Address, const void *Decoder);
    187 static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
    188                                uint64_t Address, const void *Decoder);
    189 static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
    190                                uint64_t Address, const void *Decoder);
    191 
    192 static DecodeStatus DecodeBitfieldMaskOperand(MCInst &Inst, unsigned Insn,
    193                                uint64_t Address, const void *Decoder);
    194 static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
    195                                uint64_t Address, const void *Decoder);
    196 static DecodeStatus DecodeAddrMode2IdxInstruction(MCInst &Inst,
    197                                                   unsigned Insn,
    198                                                   uint64_t Address,
    199                                                   const void *Decoder);
    200 static DecodeStatus DecodeSORegMemOperand(MCInst &Inst, unsigned Insn,
    201                                uint64_t Address, const void *Decoder);
    202 static DecodeStatus DecodeAddrMode3Instruction(MCInst &Inst,unsigned Insn,
    203                                uint64_t Address, const void *Decoder);
    204 static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Insn,
    205                                uint64_t Address, const void *Decoder);
    206 static DecodeStatus DecodeSORegRegOperand(MCInst &Inst, unsigned Insn,
    207                                uint64_t Address, const void *Decoder);
    208 
    209 static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst & Inst,
    210                                                   unsigned Insn,
    211                                                   uint64_t Adddress,
    212                                                   const void *Decoder);
    213 static DecodeStatus DecodeT2MOVTWInstruction(MCInst &Inst, unsigned Insn,
    214                                uint64_t Address, const void *Decoder);
    215 static DecodeStatus DecodeArmMOVTWInstruction(MCInst &Inst, unsigned Insn,
    216                                uint64_t Address, const void *Decoder);
    217 static DecodeStatus DecodeSMLAInstruction(MCInst &Inst, unsigned Insn,
    218                                uint64_t Address, const void *Decoder);
    219 static DecodeStatus DecodeHINTInstruction(MCInst &Inst, unsigned Insn,
    220                                uint64_t Address, const void *Decoder);
    221 static DecodeStatus DecodeCPSInstruction(MCInst &Inst, unsigned Insn,
    222                                uint64_t Address, const void *Decoder);
    223 static DecodeStatus DecodeTSTInstruction(MCInst &Inst, unsigned Insn,
    224                                uint64_t Address, const void *Decoder);
    225 static DecodeStatus DecodeSETPANInstruction(MCInst &Inst, unsigned Insn,
    226                                uint64_t Address, const void *Decoder);
    227 static DecodeStatus DecodeT2CPSInstruction(MCInst &Inst, unsigned Insn,
    228                                uint64_t Address, const void *Decoder);
    229 static DecodeStatus DecodeAddrModeImm12Operand(MCInst &Inst, unsigned Val,
    230                                uint64_t Address, const void *Decoder);
    231 static DecodeStatus DecodeAddrMode5Operand(MCInst &Inst, unsigned Val,
    232                                uint64_t Address, const void *Decoder);
    233 static DecodeStatus DecodeAddrMode5FP16Operand(MCInst &Inst, unsigned Val,
    234                                uint64_t Address, const void *Decoder);
    235 static DecodeStatus DecodeAddrMode7Operand(MCInst &Inst, unsigned Val,
    236                                uint64_t Address, const void *Decoder);
    237 static DecodeStatus DecodeT2BInstruction(MCInst &Inst, unsigned Insn,
    238                                uint64_t Address, const void *Decoder);
    239 static DecodeStatus DecodeBranchImmInstruction(MCInst &Inst,unsigned Insn,
    240                                uint64_t Address, const void *Decoder);
    241 static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
    242                                uint64_t Address, const void *Decoder);
    243 static DecodeStatus DecodeVLDST1Instruction(MCInst &Inst, unsigned Val,
    244                                uint64_t Address, const void *Decoder);
    245 static DecodeStatus DecodeVLDST2Instruction(MCInst &Inst, unsigned Val,
    246                                uint64_t Address, const void *Decoder);
    247 static DecodeStatus DecodeVLDST3Instruction(MCInst &Inst, unsigned Val,
    248                                uint64_t Address, const void *Decoder);
    249 static DecodeStatus DecodeVLDST4Instruction(MCInst &Inst, unsigned Val,
    250                                uint64_t Address, const void *Decoder);
    251 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Val,
    252                                uint64_t Address, const void *Decoder);
    253 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Val,
    254                                uint64_t Address, const void *Decoder);
    255 static DecodeStatus DecodeVLD1DupInstruction(MCInst &Inst, unsigned Val,
    256                                uint64_t Address, const void *Decoder);
    257 static DecodeStatus DecodeVLD2DupInstruction(MCInst &Inst, unsigned Val,
    258                                uint64_t Address, const void *Decoder);
    259 static DecodeStatus DecodeVLD3DupInstruction(MCInst &Inst, unsigned Val,
    260                                uint64_t Address, const void *Decoder);
    261 static DecodeStatus DecodeVLD4DupInstruction(MCInst &Inst, unsigned Val,
    262                                uint64_t Address, const void *Decoder);
    263 static DecodeStatus DecodeNEONModImmInstruction(MCInst &Inst,unsigned Val,
    264                                uint64_t Address, const void *Decoder);
    265 static DecodeStatus DecodeVSHLMaxInstruction(MCInst &Inst, unsigned Val,
    266                                uint64_t Address, const void *Decoder);
    267 static DecodeStatus DecodeShiftRight8Imm(MCInst &Inst, unsigned Val,
    268                                uint64_t Address, const void *Decoder);
    269 static DecodeStatus DecodeShiftRight16Imm(MCInst &Inst, unsigned Val,
    270                                uint64_t Address, const void *Decoder);
    271 static DecodeStatus DecodeShiftRight32Imm(MCInst &Inst, unsigned Val,
    272                                uint64_t Address, const void *Decoder);
    273 static DecodeStatus DecodeShiftRight64Imm(MCInst &Inst, unsigned Val,
    274                                uint64_t Address, const void *Decoder);
    275 static DecodeStatus DecodeTBLInstruction(MCInst &Inst, unsigned Insn,
    276                                uint64_t Address, const void *Decoder);
    277 static DecodeStatus DecodePostIdxReg(MCInst &Inst, unsigned Insn,
    278                                uint64_t Address, const void *Decoder);
    279 static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Insn,
    280                                uint64_t Address, const void *Decoder);
    281 static DecodeStatus DecodeMemBarrierOption(MCInst &Inst, unsigned Insn,
    282                                uint64_t Address, const void *Decoder);
    283 static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Insn,
    284                                uint64_t Address, const void *Decoder);
    285 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Insn,
    286                                uint64_t Address, const void *Decoder);
    287 static DecodeStatus DecodeBankedReg(MCInst &Inst, unsigned Insn,
    288                                uint64_t Address, const void *Decoder);
    289 static DecodeStatus DecodeDoubleRegLoad(MCInst &Inst, unsigned Insn,
    290                                uint64_t Address, const void *Decoder);
    291 static DecodeStatus DecodeDoubleRegStore(MCInst &Inst, unsigned Insn,
    292                                uint64_t Address, const void *Decoder);
    293 static DecodeStatus DecodeLDRPreImm(MCInst &Inst, unsigned Insn,
    294                                uint64_t Address, const void *Decoder);
    295 static DecodeStatus DecodeLDRPreReg(MCInst &Inst, unsigned Insn,
    296                                uint64_t Address, const void *Decoder);
    297 static DecodeStatus DecodeSTRPreImm(MCInst &Inst, unsigned Insn,
    298                                uint64_t Address, const void *Decoder);
    299 static DecodeStatus DecodeSTRPreReg(MCInst &Inst, unsigned Insn,
    300                                uint64_t Address, const void *Decoder);
    301 static DecodeStatus DecodeVLD1LN(MCInst &Inst, unsigned Insn,
    302                                uint64_t Address, const void *Decoder);
    303 static DecodeStatus DecodeVLD2LN(MCInst &Inst, unsigned Insn,
    304                                uint64_t Address, const void *Decoder);
    305 static DecodeStatus DecodeVLD3LN(MCInst &Inst, unsigned Insn,
    306                                uint64_t Address, const void *Decoder);
    307 static DecodeStatus DecodeVLD4LN(MCInst &Inst, unsigned Insn,
    308                                uint64_t Address, const void *Decoder);
    309 static DecodeStatus DecodeVST1LN(MCInst &Inst, unsigned Insn,
    310                                uint64_t Address, const void *Decoder);
    311 static DecodeStatus DecodeVST2LN(MCInst &Inst, unsigned Insn,
    312                                uint64_t Address, const void *Decoder);
    313 static DecodeStatus DecodeVST3LN(MCInst &Inst, unsigned Insn,
    314                                uint64_t Address, const void *Decoder);
    315 static DecodeStatus DecodeVST4LN(MCInst &Inst, unsigned Insn,
    316                                uint64_t Address, const void *Decoder);
    317 static DecodeStatus DecodeVMOVSRR(MCInst &Inst, unsigned Insn,
    318                                uint64_t Address, const void *Decoder);
    319 static DecodeStatus DecodeVMOVRRS(MCInst &Inst, unsigned Insn,
    320                                uint64_t Address, const void *Decoder);
    321 static DecodeStatus DecodeSwap(MCInst &Inst, unsigned Insn,
    322                                uint64_t Address, const void *Decoder);
    323 static DecodeStatus DecodeVCVTD(MCInst &Inst, unsigned Insn,
    324                                 uint64_t Address, const void *Decoder);
    325 static DecodeStatus DecodeVCVTQ(MCInst &Inst, unsigned Insn,
    326                                 uint64_t Address, const void *Decoder);
    327 static DecodeStatus DecodeNEONComplexLane64Instruction(MCInst &Inst,
    328                                                        unsigned Val,
    329                                                        uint64_t Address,
    330                                                        const void *Decoder);
    331 
    332 static DecodeStatus DecodeThumbAddSpecialReg(MCInst &Inst, uint16_t Insn,
    333                                uint64_t Address, const void *Decoder);
    334 static DecodeStatus DecodeThumbBROperand(MCInst &Inst, unsigned Val,
    335                                uint64_t Address, const void *Decoder);
    336 static DecodeStatus DecodeT2BROperand(MCInst &Inst, unsigned Val,
    337                                uint64_t Address, const void *Decoder);
    338 static DecodeStatus DecodeThumbCmpBROperand(MCInst &Inst, unsigned Val,
    339                                uint64_t Address, const void *Decoder);
    340 static DecodeStatus DecodeThumbAddrModeRR(MCInst &Inst, unsigned Val,
    341                                uint64_t Address, const void *Decoder);
    342 static DecodeStatus DecodeThumbAddrModeIS(MCInst &Inst, unsigned Val,
    343                                uint64_t Address, const void *Decoder);
    344 static DecodeStatus DecodeThumbAddrModePC(MCInst &Inst, unsigned Val,
    345                                uint64_t Address, const void *Decoder);
    346 static DecodeStatus DecodeThumbAddrModeSP(MCInst &Inst, unsigned Val,
    347                                uint64_t Address, const void *Decoder);
    348 static DecodeStatus DecodeT2AddrModeSOReg(MCInst &Inst, unsigned Val,
    349                                uint64_t Address, const void *Decoder);
    350 static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Val,
    351                                uint64_t Address, const void *Decoder);
    352 static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
    353                                uint64_t Address, const void* Decoder);
    354 static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
    355                                uint64_t Address, const void* Decoder);
    356 static DecodeStatus DecodeT2LoadT(MCInst &Inst, unsigned Insn,
    357                                uint64_t Address, const void* Decoder);
    358 static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
    359                                uint64_t Address, const void* Decoder);
    360 static DecodeStatus DecodeT2Imm8S4(MCInst &Inst, unsigned Val,
    361                                uint64_t Address, const void *Decoder);
    362 static DecodeStatus DecodeT2AddrModeImm8s4(MCInst &Inst, unsigned Val,
    363                                uint64_t Address, const void *Decoder);
    364 static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst &Inst,unsigned Val,
    365                                uint64_t Address, const void *Decoder);
    366 static DecodeStatus DecodeT2Imm8(MCInst &Inst, unsigned Val,
    367                                uint64_t Address, const void *Decoder);
    368 static DecodeStatus DecodeT2AddrModeImm8(MCInst &Inst, unsigned Val,
    369                                uint64_t Address, const void *Decoder);
    370 static DecodeStatus DecodeThumbAddSPImm(MCInst &Inst, uint16_t Val,
    371                                uint64_t Address, const void *Decoder);
    372 static DecodeStatus DecodeThumbAddSPReg(MCInst &Inst, uint16_t Insn,
    373                                 uint64_t Address, const void *Decoder);
    374 static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
    375                                 uint64_t Address, const void *Decoder);
    376 static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
    377                                 uint64_t Address, const void *Decoder);
    378 static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Insn,
    379                                 uint64_t Address, const void *Decoder);
    380 static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
    381                                 uint64_t Address, const void *Decoder);
    382 static DecodeStatus DecodeThumbTableBranch(MCInst &Inst, unsigned Val,
    383                                 uint64_t Address, const void *Decoder);
    384 static DecodeStatus DecodeThumb2BCCInstruction(MCInst &Inst, unsigned Val,
    385                                 uint64_t Address, const void *Decoder);
    386 static DecodeStatus DecodeT2SOImm(MCInst &Inst, unsigned Val,
    387                                 uint64_t Address, const void *Decoder);
    388 static DecodeStatus DecodeThumbBCCTargetOperand(MCInst &Inst,unsigned Val,
    389                                 uint64_t Address, const void *Decoder);
    390 static DecodeStatus DecodeThumbBLTargetOperand(MCInst &Inst, unsigned Val,
    391                                 uint64_t Address, const void *Decoder);
    392 static DecodeStatus DecodeIT(MCInst &Inst, unsigned Val,
    393                                 uint64_t Address, const void *Decoder);
    394 static DecodeStatus DecodeT2LDRDPreInstruction(MCInst &Inst,unsigned Insn,
    395                                uint64_t Address, const void *Decoder);
    396 static DecodeStatus DecodeT2STRDPreInstruction(MCInst &Inst,unsigned Insn,
    397                                uint64_t Address, const void *Decoder);
    398 static DecodeStatus DecodeT2Adr(MCInst &Inst, unsigned Val,
    399                                 uint64_t Address, const void *Decoder);
    400 static DecodeStatus DecodeT2LdStPre(MCInst &Inst, unsigned Val,
    401                                 uint64_t Address, const void *Decoder);
    402 static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, unsigned Val,
    403                                 uint64_t Address, const void *Decoder);
    404 
    405 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
    406                                 uint64_t Address, const void *Decoder);
    407 static DecodeStatus DecoderForMRRC2AndMCRR2(MCInst &Inst, unsigned Val,
    408                                             uint64_t Address, const void *Decoder);
    409 static DecodeStatus DecodeForVMRSandVMSR(MCInst &Inst, unsigned Val,
    410                                          uint64_t Address, const void *Decoder);
    411 
    412 #include "ARMGenDisassemblerTables.inc"
    413 
    414 static MCDisassembler *createARMDisassembler(const Target &T,
    415                                              const MCSubtargetInfo &STI,
    416                                              MCContext &Ctx) {
    417   return new ARMDisassembler(STI, Ctx);
    418 }
    419 
    420 static MCDisassembler *createThumbDisassembler(const Target &T,
    421                                                const MCSubtargetInfo &STI,
    422                                                MCContext &Ctx) {
    423   return new ThumbDisassembler(STI, Ctx);
    424 }
    425 
    426 // Post-decoding checks
    427 static DecodeStatus checkDecodedInstruction(MCInst &MI, uint64_t &Size,
    428                                             uint64_t Address, raw_ostream &OS,
    429                                             raw_ostream &CS,
    430                                             uint32_t Insn,
    431                                             DecodeStatus Result) {
    432   switch (MI.getOpcode()) {
    433     case ARM::HVC: {
    434       // HVC is undefined if condition = 0xf otherwise upredictable
    435       // if condition != 0xe
    436       uint32_t Cond = (Insn >> 28) & 0xF;
    437       if (Cond == 0xF)
    438         return MCDisassembler::Fail;
    439       if (Cond != 0xE)
    440         return MCDisassembler::SoftFail;
    441       return Result;
    442     }
    443     default: return Result;
    444   }
    445 }
    446 
    447 DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
    448                                              ArrayRef<uint8_t> Bytes,
    449                                              uint64_t Address, raw_ostream &OS,
    450                                              raw_ostream &CS) const {
    451   CommentStream = &CS;
    452 
    453   assert(!STI.getFeatureBits()[ARM::ModeThumb] &&
    454          "Asked to disassemble an ARM instruction but Subtarget is in Thumb "
    455          "mode!");
    456 
    457   // We want to read exactly 4 bytes of data.
    458   if (Bytes.size() < 4) {
    459     Size = 0;
    460     return MCDisassembler::Fail;
    461   }
    462 
    463   // Encoded as a small-endian 32-bit word in the stream.
    464   uint32_t Insn =
    465       (Bytes[3] << 24) | (Bytes[2] << 16) | (Bytes[1] << 8) | (Bytes[0] << 0);
    466 
    467   // Calling the auto-generated decoder function.
    468   DecodeStatus Result =
    469       decodeInstruction(DecoderTableARM32, MI, Insn, Address, this, STI);
    470   if (Result != MCDisassembler::Fail) {
    471     Size = 4;
    472     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
    473   }
    474 
    475   struct DecodeTable {
    476     const uint8_t *P;
    477     bool DecodePred;
    478   };
    479 
    480   const DecodeTable Tables[] = {
    481       {DecoderTableVFP32, false},      {DecoderTableVFPV832, false},
    482       {DecoderTableNEONData32, true},  {DecoderTableNEONLoadStore32, true},
    483       {DecoderTableNEONDup32, true},   {DecoderTablev8NEON32, false},
    484       {DecoderTablev8Crypto32, false},
    485   };
    486 
    487   for (auto Table : Tables) {
    488     Result = decodeInstruction(Table.P, MI, Insn, Address, this, STI);
    489     if (Result != MCDisassembler::Fail) {
    490       Size = 4;
    491       // Add a fake predicate operand, because we share these instruction
    492       // definitions with Thumb2 where these instructions are predicable.
    493       if (Table.DecodePred && !DecodePredicateOperand(MI, 0xE, Address, this))
    494         return MCDisassembler::Fail;
    495       return Result;
    496     }
    497   }
    498 
    499   Result =
    500       decodeInstruction(DecoderTableCoProc32, MI, Insn, Address, this, STI);
    501   if (Result != MCDisassembler::Fail) {
    502     Size = 4;
    503     return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
    504   }
    505 
    506   Size = 4;
    507   return MCDisassembler::Fail;
    508 }
    509 
    510 namespace llvm {
    511 
    512 extern const MCInstrDesc ARMInsts[];
    513 
    514 } // end namespace llvm
    515 
    516 /// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the
    517 /// immediate Value in the MCInst.  The immediate Value has had any PC
    518 /// adjustment made by the caller.  If the instruction is a branch instruction
    519 /// then isBranch is true, else false.  If the getOpInfo() function was set as
    520 /// part of the setupForSymbolicDisassembly() call then that function is called
    521 /// to get any symbolic information at the Address for this instruction.  If
    522 /// that returns non-zero then the symbolic information it returns is used to
    523 /// create an MCExpr and that is added as an operand to the MCInst.  If
    524 /// getOpInfo() returns zero and isBranch is true then a symbol look up for
    525 /// Value is done and if a symbol is found an MCExpr is created with that, else
    526 /// an MCExpr with Value is created.  This function returns true if it adds an
    527 /// operand to the MCInst and false otherwise.
    528 static bool tryAddingSymbolicOperand(uint64_t Address, int32_t Value,
    529                                      bool isBranch, uint64_t InstSize,
    530                                      MCInst &MI, const void *Decoder) {
    531   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
    532   // FIXME: Does it make sense for value to be negative?
    533   return Dis->tryAddingSymbolicOperand(MI, (uint32_t)Value, Address, isBranch,
    534                                        /* Offset */ 0, InstSize);
    535 }
    536 
    537 /// tryAddingPcLoadReferenceComment - trys to add a comment as to what is being
    538 /// referenced by a load instruction with the base register that is the Pc.
    539 /// These can often be values in a literal pool near the Address of the
    540 /// instruction.  The Address of the instruction and its immediate Value are
    541 /// used as a possible literal pool entry.  The SymbolLookUp call back will
    542 /// return the name of a symbol referenced by the literal pool's entry if
    543 /// the referenced address is that of a symbol.  Or it will return a pointer to
    544 /// a literal 'C' string if the referenced address of the literal pool's entry
    545 /// is an address into a section with 'C' string literals.
    546 static void tryAddingPcLoadReferenceComment(uint64_t Address, int Value,
    547                                             const void *Decoder) {
    548   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
    549   Dis->tryAddingPcLoadReferenceComment(Value, Address);
    550 }
    551 
    552 // Thumb1 instructions don't have explicit S bits.  Rather, they
    553 // implicitly set CPSR.  Since it's not represented in the encoding, the
    554 // auto-generated decoder won't inject the CPSR operand.  We need to fix
    555 // that as a post-pass.
    556 static void AddThumb1SBit(MCInst &MI, bool InITBlock) {
    557   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
    558   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
    559   MCInst::iterator I = MI.begin();
    560   for (unsigned i = 0; i < NumOps; ++i, ++I) {
    561     if (I == MI.end()) break;
    562     if (OpInfo[i].isOptionalDef() && OpInfo[i].RegClass == ARM::CCRRegClassID) {
    563       if (i > 0 && OpInfo[i-1].isPredicate()) continue;
    564       MI.insert(I, MCOperand::createReg(InITBlock ? 0 : ARM::CPSR));
    565       return;
    566     }
    567   }
    568 
    569   MI.insert(I, MCOperand::createReg(InITBlock ? 0 : ARM::CPSR));
    570 }
    571 
    572 // Most Thumb instructions don't have explicit predicates in the
    573 // encoding, but rather get their predicates from IT context.  We need
    574 // to fix up the predicate operands using this context information as a
    575 // post-pass.
    576 MCDisassembler::DecodeStatus
    577 ThumbDisassembler::AddThumbPredicate(MCInst &MI) const {
    578   MCDisassembler::DecodeStatus S = Success;
    579 
    580   const FeatureBitset &FeatureBits = getSubtargetInfo().getFeatureBits();
    581 
    582   // A few instructions actually have predicates encoded in them.  Don't
    583   // try to overwrite it if we're seeing one of those.
    584   switch (MI.getOpcode()) {
    585     case ARM::tBcc:
    586     case ARM::t2Bcc:
    587     case ARM::tCBZ:
    588     case ARM::tCBNZ:
    589     case ARM::tCPS:
    590     case ARM::t2CPS3p:
    591     case ARM::t2CPS2p:
    592     case ARM::t2CPS1p:
    593     case ARM::tMOVSr:
    594     case ARM::tSETEND:
    595       // Some instructions (mostly conditional branches) are not
    596       // allowed in IT blocks.
    597       if (ITBlock.instrInITBlock())
    598         S = SoftFail;
    599       else
    600         return Success;
    601       break;
    602     case ARM::t2HINT:
    603       if (MI.getOperand(0).getImm() == 0x10 && (FeatureBits[ARM::FeatureRAS]) != 0)
    604         S = SoftFail;
    605       break;
    606     case ARM::tB:
    607     case ARM::t2B:
    608     case ARM::t2TBB:
    609     case ARM::t2TBH:
    610       // Some instructions (mostly unconditional branches) can
    611       // only appears at the end of, or outside of, an IT.
    612       if (ITBlock.instrInITBlock() && !ITBlock.instrLastInITBlock())
    613         S = SoftFail;
    614       break;
    615     default:
    616       break;
    617   }
    618 
    619   // If we're in an IT block, base the predicate on that.  Otherwise,
    620   // assume a predicate of AL.
    621   unsigned CC;
    622   CC = ITBlock.getITCC();
    623   if (CC == 0xF)
    624     CC = ARMCC::AL;
    625   if (ITBlock.instrInITBlock())
    626     ITBlock.advanceITState();
    627 
    628   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
    629   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
    630   MCInst::iterator I = MI.begin();
    631   for (unsigned i = 0; i < NumOps; ++i, ++I) {
    632     if (I == MI.end()) break;
    633     if (OpInfo[i].isPredicate()) {
    634       I = MI.insert(I, MCOperand::createImm(CC));
    635       ++I;
    636       if (CC == ARMCC::AL)
    637         MI.insert(I, MCOperand::createReg(0));
    638       else
    639         MI.insert(I, MCOperand::createReg(ARM::CPSR));
    640       return S;
    641     }
    642   }
    643 
    644   I = MI.insert(I, MCOperand::createImm(CC));
    645   ++I;
    646   if (CC == ARMCC::AL)
    647     MI.insert(I, MCOperand::createReg(0));
    648   else
    649     MI.insert(I, MCOperand::createReg(ARM::CPSR));
    650 
    651   return S;
    652 }
    653 
    654 // Thumb VFP instructions are a special case.  Because we share their
    655 // encodings between ARM and Thumb modes, and they are predicable in ARM
    656 // mode, the auto-generated decoder will give them an (incorrect)
    657 // predicate operand.  We need to rewrite these operands based on the IT
    658 // context as a post-pass.
    659 void ThumbDisassembler::UpdateThumbVFPPredicate(MCInst &MI) const {
    660   unsigned CC;
    661   CC = ITBlock.getITCC();
    662   if (CC == 0xF)
    663     CC = ARMCC::AL;
    664   if (ITBlock.instrInITBlock())
    665     ITBlock.advanceITState();
    666 
    667   const MCOperandInfo *OpInfo = ARMInsts[MI.getOpcode()].OpInfo;
    668   MCInst::iterator I = MI.begin();
    669   unsigned short NumOps = ARMInsts[MI.getOpcode()].NumOperands;
    670   for (unsigned i = 0; i < NumOps; ++i, ++I) {
    671     if (OpInfo[i].isPredicate() ) {
    672       I->setImm(CC);
    673       ++I;
    674       if (CC == ARMCC::AL)
    675         I->setReg(0);
    676       else
    677         I->setReg(ARM::CPSR);
    678       return;
    679     }
    680   }
    681 }
    682 
    683 DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
    684                                                ArrayRef<uint8_t> Bytes,
    685                                                uint64_t Address,
    686                                                raw_ostream &OS,
    687                                                raw_ostream &CS) const {
    688   CommentStream = &CS;
    689 
    690   assert(STI.getFeatureBits()[ARM::ModeThumb] &&
    691          "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
    692 
    693   // We want to read exactly 2 bytes of data.
    694   if (Bytes.size() < 2) {
    695     Size = 0;
    696     return MCDisassembler::Fail;
    697   }
    698 
    699   uint16_t Insn16 = (Bytes[1] << 8) | Bytes[0];
    700   DecodeStatus Result =
    701       decodeInstruction(DecoderTableThumb16, MI, Insn16, Address, this, STI);
    702   if (Result != MCDisassembler::Fail) {
    703     Size = 2;
    704     Check(Result, AddThumbPredicate(MI));
    705     return Result;
    706   }
    707 
    708   Result = decodeInstruction(DecoderTableThumbSBit16, MI, Insn16, Address, this,
    709                              STI);
    710   if (Result) {
    711     Size = 2;
    712     bool InITBlock = ITBlock.instrInITBlock();
    713     Check(Result, AddThumbPredicate(MI));
    714     AddThumb1SBit(MI, InITBlock);
    715     return Result;
    716   }
    717 
    718   Result =
    719       decodeInstruction(DecoderTableThumb216, MI, Insn16, Address, this, STI);
    720   if (Result != MCDisassembler::Fail) {
    721     Size = 2;
    722 
    723     // Nested IT blocks are UNPREDICTABLE.  Must be checked before we add
    724     // the Thumb predicate.
    725     if (MI.getOpcode() == ARM::t2IT && ITBlock.instrInITBlock())
    726       Result = MCDisassembler::SoftFail;
    727 
    728     Check(Result, AddThumbPredicate(MI));
    729 
    730     // If we find an IT instruction, we need to parse its condition
    731     // code and mask operands so that we can apply them correctly
    732     // to the subsequent instructions.
    733     if (MI.getOpcode() == ARM::t2IT) {
    734       unsigned Firstcond = MI.getOperand(0).getImm();
    735       unsigned Mask = MI.getOperand(1).getImm();
    736       ITBlock.setITState(Firstcond, Mask);
    737 
    738       // An IT instruction that would give a 'NV' predicate is unpredictable.
    739       if (Firstcond == ARMCC::AL && !isPowerOf2_32(Mask))
    740         CS << "unpredictable IT predicate sequence";
    741     }
    742 
    743     return Result;
    744   }
    745 
    746   // We want to read exactly 4 bytes of data.
    747   if (Bytes.size() < 4) {
    748     Size = 0;
    749     return MCDisassembler::Fail;
    750   }
    751 
    752   uint32_t Insn32 =
    753       (Bytes[3] << 8) | (Bytes[2] << 0) | (Bytes[1] << 24) | (Bytes[0] << 16);
    754   Result =
    755       decodeInstruction(DecoderTableThumb32, MI, Insn32, Address, this, STI);
    756   if (Result != MCDisassembler::Fail) {
    757     Size = 4;
    758     bool InITBlock = ITBlock.instrInITBlock();
    759     Check(Result, AddThumbPredicate(MI));
    760     AddThumb1SBit(MI, InITBlock);
    761     return Result;
    762   }
    763 
    764   Result =
    765       decodeInstruction(DecoderTableThumb232, MI, Insn32, Address, this, STI);
    766   if (Result != MCDisassembler::Fail) {
    767     Size = 4;
    768     Check(Result, AddThumbPredicate(MI));
    769     return Result;
    770   }
    771 
    772   if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
    773     Result =
    774         decodeInstruction(DecoderTableVFP32, MI, Insn32, Address, this, STI);
    775     if (Result != MCDisassembler::Fail) {
    776       Size = 4;
    777       UpdateThumbVFPPredicate(MI);
    778       return Result;
    779     }
    780   }
    781 
    782   Result =
    783       decodeInstruction(DecoderTableVFPV832, MI, Insn32, Address, this, STI);
    784   if (Result != MCDisassembler::Fail) {
    785     Size = 4;
    786     return Result;
    787   }
    788 
    789   if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
    790     Result = decodeInstruction(DecoderTableNEONDup32, MI, Insn32, Address, this,
    791                                STI);
    792     if (Result != MCDisassembler::Fail) {
    793       Size = 4;
    794       Check(Result, AddThumbPredicate(MI));
    795       return Result;
    796     }
    797   }
    798 
    799   if (fieldFromInstruction(Insn32, 24, 8) == 0xF9) {
    800     uint32_t NEONLdStInsn = Insn32;
    801     NEONLdStInsn &= 0xF0FFFFFF;
    802     NEONLdStInsn |= 0x04000000;
    803     Result = decodeInstruction(DecoderTableNEONLoadStore32, MI, NEONLdStInsn,
    804                                Address, this, STI);
    805     if (Result != MCDisassembler::Fail) {
    806       Size = 4;
    807       Check(Result, AddThumbPredicate(MI));
    808       return Result;
    809     }
    810   }
    811 
    812   if (fieldFromInstruction(Insn32, 24, 4) == 0xF) {
    813     uint32_t NEONDataInsn = Insn32;
    814     NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
    815     NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
    816     NEONDataInsn |= 0x12000000; // Set bits 28 and 25
    817     Result = decodeInstruction(DecoderTableNEONData32, MI, NEONDataInsn,
    818                                Address, this, STI);
    819     if (Result != MCDisassembler::Fail) {
    820       Size = 4;
    821       Check(Result, AddThumbPredicate(MI));
    822       return Result;
    823     }
    824 
    825     uint32_t NEONCryptoInsn = Insn32;
    826     NEONCryptoInsn &= 0xF0FFFFFF; // Clear bits 27-24
    827     NEONCryptoInsn |= (NEONCryptoInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
    828     NEONCryptoInsn |= 0x12000000; // Set bits 28 and 25
    829     Result = decodeInstruction(DecoderTablev8Crypto32, MI, NEONCryptoInsn,
    830                                Address, this, STI);
    831     if (Result != MCDisassembler::Fail) {
    832       Size = 4;
    833       return Result;
    834     }
    835 
    836     uint32_t NEONv8Insn = Insn32;
    837     NEONv8Insn &= 0xF3FFFFFF; // Clear bits 27-26
    838     Result = decodeInstruction(DecoderTablev8NEON32, MI, NEONv8Insn, Address,
    839                                this, STI);
    840     if (Result != MCDisassembler::Fail) {
    841       Size = 4;
    842       return Result;
    843     }
    844   }
    845 
    846   Result =
    847       decodeInstruction(DecoderTableThumb2CoProc32, MI, Insn32, Address, this, STI);
    848   if (Result != MCDisassembler::Fail) {
    849     Size = 4;
    850     Check(Result, AddThumbPredicate(MI));
    851     return Result;
    852   }
    853 
    854   Size = 0;
    855   return MCDisassembler::Fail;
    856 }
    857 
    858 extern "C" void LLVMInitializeARMDisassembler() {
    859   TargetRegistry::RegisterMCDisassembler(getTheARMLETarget(),
    860                                          createARMDisassembler);
    861   TargetRegistry::RegisterMCDisassembler(getTheARMBETarget(),
    862                                          createARMDisassembler);
    863   TargetRegistry::RegisterMCDisassembler(getTheThumbLETarget(),
    864                                          createThumbDisassembler);
    865   TargetRegistry::RegisterMCDisassembler(getTheThumbBETarget(),
    866                                          createThumbDisassembler);
    867 }
    868 
    869 static const uint16_t GPRDecoderTable[] = {
    870   ARM::R0, ARM::R1, ARM::R2, ARM::R3,
    871   ARM::R4, ARM::R5, ARM::R6, ARM::R7,
    872   ARM::R8, ARM::R9, ARM::R10, ARM::R11,
    873   ARM::R12, ARM::SP, ARM::LR, ARM::PC
    874 };
    875 
    876 static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
    877                                    uint64_t Address, const void *Decoder) {
    878   if (RegNo > 15)
    879     return MCDisassembler::Fail;
    880 
    881   unsigned Register = GPRDecoderTable[RegNo];
    882   Inst.addOperand(MCOperand::createReg(Register));
    883   return MCDisassembler::Success;
    884 }
    885 
    886 static DecodeStatus
    887 DecodeGPRnopcRegisterClass(MCInst &Inst, unsigned RegNo,
    888                            uint64_t Address, const void *Decoder) {
    889   DecodeStatus S = MCDisassembler::Success;
    890 
    891   if (RegNo == 15)
    892     S = MCDisassembler::SoftFail;
    893 
    894   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
    895 
    896   return S;
    897 }
    898 
    899 static DecodeStatus
    900 DecodeGPRwithAPSRRegisterClass(MCInst &Inst, unsigned RegNo,
    901                                uint64_t Address, const void *Decoder) {
    902   DecodeStatus S = MCDisassembler::Success;
    903 
    904   if (RegNo == 15)
    905   {
    906     Inst.addOperand(MCOperand::createReg(ARM::APSR_NZCV));
    907     return MCDisassembler::Success;
    908   }
    909 
    910   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
    911   return S;
    912 }
    913 
    914 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
    915                                    uint64_t Address, const void *Decoder) {
    916   if (RegNo > 7)
    917     return MCDisassembler::Fail;
    918   return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
    919 }
    920 
    921 static const uint16_t GPRPairDecoderTable[] = {
    922   ARM::R0_R1, ARM::R2_R3,   ARM::R4_R5,  ARM::R6_R7,
    923   ARM::R8_R9, ARM::R10_R11, ARM::R12_SP
    924 };
    925 
    926 static DecodeStatus DecodeGPRPairRegisterClass(MCInst &Inst, unsigned RegNo,
    927                                    uint64_t Address, const void *Decoder) {
    928   DecodeStatus S = MCDisassembler::Success;
    929 
    930   if (RegNo > 13)
    931     return MCDisassembler::Fail;
    932 
    933   if ((RegNo & 1) || RegNo == 0xe)
    934      S = MCDisassembler::SoftFail;
    935 
    936   unsigned RegisterPair = GPRPairDecoderTable[RegNo/2];
    937   Inst.addOperand(MCOperand::createReg(RegisterPair));
    938   return S;
    939 }
    940 
    941 static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
    942                                    uint64_t Address, const void *Decoder) {
    943   unsigned Register = 0;
    944   switch (RegNo) {
    945     case 0:
    946       Register = ARM::R0;
    947       break;
    948     case 1:
    949       Register = ARM::R1;
    950       break;
    951     case 2:
    952       Register = ARM::R2;
    953       break;
    954     case 3:
    955       Register = ARM::R3;
    956       break;
    957     case 9:
    958       Register = ARM::R9;
    959       break;
    960     case 12:
    961       Register = ARM::R12;
    962       break;
    963     default:
    964       return MCDisassembler::Fail;
    965     }
    966 
    967   Inst.addOperand(MCOperand::createReg(Register));
    968   return MCDisassembler::Success;
    969 }
    970 
    971 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
    972                                    uint64_t Address, const void *Decoder) {
    973   DecodeStatus S = MCDisassembler::Success;
    974 
    975   const FeatureBitset &featureBits =
    976     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
    977 
    978   if ((RegNo == 13 && !featureBits[ARM::HasV8Ops]) || RegNo == 15)
    979     S = MCDisassembler::SoftFail;
    980 
    981   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
    982   return S;
    983 }
    984 
    985 static const uint16_t SPRDecoderTable[] = {
    986      ARM::S0,  ARM::S1,  ARM::S2,  ARM::S3,
    987      ARM::S4,  ARM::S5,  ARM::S6,  ARM::S7,
    988      ARM::S8,  ARM::S9, ARM::S10, ARM::S11,
    989     ARM::S12, ARM::S13, ARM::S14, ARM::S15,
    990     ARM::S16, ARM::S17, ARM::S18, ARM::S19,
    991     ARM::S20, ARM::S21, ARM::S22, ARM::S23,
    992     ARM::S24, ARM::S25, ARM::S26, ARM::S27,
    993     ARM::S28, ARM::S29, ARM::S30, ARM::S31
    994 };
    995 
    996 static DecodeStatus DecodeSPRRegisterClass(MCInst &Inst, unsigned RegNo,
    997                                    uint64_t Address, const void *Decoder) {
    998   if (RegNo > 31)
    999     return MCDisassembler::Fail;
   1000 
   1001   unsigned Register = SPRDecoderTable[RegNo];
   1002   Inst.addOperand(MCOperand::createReg(Register));
   1003   return MCDisassembler::Success;
   1004 }
   1005 
   1006 static DecodeStatus DecodeHPRRegisterClass(MCInst &Inst, unsigned RegNo,
   1007                                    uint64_t Address, const void *Decoder) {
   1008   return DecodeSPRRegisterClass(Inst, RegNo, Address, Decoder);
   1009 }
   1010 
   1011 static const uint16_t DPRDecoderTable[] = {
   1012      ARM::D0,  ARM::D1,  ARM::D2,  ARM::D3,
   1013      ARM::D4,  ARM::D5,  ARM::D6,  ARM::D7,
   1014      ARM::D8,  ARM::D9, ARM::D10, ARM::D11,
   1015     ARM::D12, ARM::D13, ARM::D14, ARM::D15,
   1016     ARM::D16, ARM::D17, ARM::D18, ARM::D19,
   1017     ARM::D20, ARM::D21, ARM::D22, ARM::D23,
   1018     ARM::D24, ARM::D25, ARM::D26, ARM::D27,
   1019     ARM::D28, ARM::D29, ARM::D30, ARM::D31
   1020 };
   1021 
   1022 static DecodeStatus DecodeDPRRegisterClass(MCInst &Inst, unsigned RegNo,
   1023                                    uint64_t Address, const void *Decoder) {
   1024   const FeatureBitset &featureBits =
   1025     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
   1026 
   1027   bool hasD16 = featureBits[ARM::FeatureD16];
   1028 
   1029   if (RegNo > 31 || (hasD16 && RegNo > 15))
   1030     return MCDisassembler::Fail;
   1031 
   1032   unsigned Register = DPRDecoderTable[RegNo];
   1033   Inst.addOperand(MCOperand::createReg(Register));
   1034   return MCDisassembler::Success;
   1035 }
   1036 
   1037 static DecodeStatus DecodeDPR_8RegisterClass(MCInst &Inst, unsigned RegNo,
   1038                                    uint64_t Address, const void *Decoder) {
   1039   if (RegNo > 7)
   1040     return MCDisassembler::Fail;
   1041   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
   1042 }
   1043 
   1044 static DecodeStatus
   1045 DecodeDPR_VFP2RegisterClass(MCInst &Inst, unsigned RegNo,
   1046                             uint64_t Address, const void *Decoder) {
   1047   if (RegNo > 15)
   1048     return MCDisassembler::Fail;
   1049   return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
   1050 }
   1051 
   1052 static const uint16_t QPRDecoderTable[] = {
   1053      ARM::Q0,  ARM::Q1,  ARM::Q2,  ARM::Q3,
   1054      ARM::Q4,  ARM::Q5,  ARM::Q6,  ARM::Q7,
   1055      ARM::Q8,  ARM::Q9, ARM::Q10, ARM::Q11,
   1056     ARM::Q12, ARM::Q13, ARM::Q14, ARM::Q15
   1057 };
   1058 
   1059 static DecodeStatus DecodeQPRRegisterClass(MCInst &Inst, unsigned RegNo,
   1060                                    uint64_t Address, const void *Decoder) {
   1061   if (RegNo > 31 || (RegNo & 1) != 0)
   1062     return MCDisassembler::Fail;
   1063   RegNo >>= 1;
   1064 
   1065   unsigned Register = QPRDecoderTable[RegNo];
   1066   Inst.addOperand(MCOperand::createReg(Register));
   1067   return MCDisassembler::Success;
   1068 }
   1069 
   1070 static const uint16_t DPairDecoderTable[] = {
   1071   ARM::Q0,  ARM::D1_D2,   ARM::Q1,  ARM::D3_D4,   ARM::Q2,  ARM::D5_D6,
   1072   ARM::Q3,  ARM::D7_D8,   ARM::Q4,  ARM::D9_D10,  ARM::Q5,  ARM::D11_D12,
   1073   ARM::Q6,  ARM::D13_D14, ARM::Q7,  ARM::D15_D16, ARM::Q8,  ARM::D17_D18,
   1074   ARM::Q9,  ARM::D19_D20, ARM::Q10, ARM::D21_D22, ARM::Q11, ARM::D23_D24,
   1075   ARM::Q12, ARM::D25_D26, ARM::Q13, ARM::D27_D28, ARM::Q14, ARM::D29_D30,
   1076   ARM::Q15
   1077 };
   1078 
   1079 static DecodeStatus DecodeDPairRegisterClass(MCInst &Inst, unsigned RegNo,
   1080                                    uint64_t Address, const void *Decoder) {
   1081   if (RegNo > 30)
   1082     return MCDisassembler::Fail;
   1083 
   1084   unsigned Register = DPairDecoderTable[RegNo];
   1085   Inst.addOperand(MCOperand::createReg(Register));
   1086   return MCDisassembler::Success;
   1087 }
   1088 
   1089 static const uint16_t DPairSpacedDecoderTable[] = {
   1090   ARM::D0_D2,   ARM::D1_D3,   ARM::D2_D4,   ARM::D3_D5,
   1091   ARM::D4_D6,   ARM::D5_D7,   ARM::D6_D8,   ARM::D7_D9,
   1092   ARM::D8_D10,  ARM::D9_D11,  ARM::D10_D12, ARM::D11_D13,
   1093   ARM::D12_D14, ARM::D13_D15, ARM::D14_D16, ARM::D15_D17,
   1094   ARM::D16_D18, ARM::D17_D19, ARM::D18_D20, ARM::D19_D21,
   1095   ARM::D20_D22, ARM::D21_D23, ARM::D22_D24, ARM::D23_D25,
   1096   ARM::D24_D26, ARM::D25_D27, ARM::D26_D28, ARM::D27_D29,
   1097   ARM::D28_D30, ARM::D29_D31
   1098 };
   1099 
   1100 static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst &Inst,
   1101                                                    unsigned RegNo,
   1102                                                    uint64_t Address,
   1103                                                    const void *Decoder) {
   1104   if (RegNo > 29)
   1105     return MCDisassembler::Fail;
   1106 
   1107   unsigned Register = DPairSpacedDecoderTable[RegNo];
   1108   Inst.addOperand(MCOperand::createReg(Register));
   1109   return MCDisassembler::Success;
   1110 }
   1111 
   1112 static DecodeStatus DecodePredicateOperand(MCInst &Inst, unsigned Val,
   1113                                uint64_t Address, const void *Decoder) {
   1114   if (Val == 0xF) return MCDisassembler::Fail;
   1115   // AL predicate is not allowed on Thumb1 branches.
   1116   if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
   1117     return MCDisassembler::Fail;
   1118   Inst.addOperand(MCOperand::createImm(Val));
   1119   if (Val == ARMCC::AL) {
   1120     Inst.addOperand(MCOperand::createReg(0));
   1121   } else
   1122     Inst.addOperand(MCOperand::createReg(ARM::CPSR));
   1123   return MCDisassembler::Success;
   1124 }
   1125 
   1126 static DecodeStatus DecodeCCOutOperand(MCInst &Inst, unsigned Val,
   1127                                uint64_t Address, const void *Decoder) {
   1128   if (Val)
   1129     Inst.addOperand(MCOperand::createReg(ARM::CPSR));
   1130   else
   1131     Inst.addOperand(MCOperand::createReg(0));
   1132   return MCDisassembler::Success;
   1133 }
   1134 
   1135 static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Val,
   1136                                uint64_t Address, const void *Decoder) {
   1137   DecodeStatus S = MCDisassembler::Success;
   1138 
   1139   unsigned Rm = fieldFromInstruction(Val, 0, 4);
   1140   unsigned type = fieldFromInstruction(Val, 5, 2);
   1141   unsigned imm = fieldFromInstruction(Val, 7, 5);
   1142 
   1143   // Register-immediate
   1144   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
   1145     return MCDisassembler::Fail;
   1146 
   1147   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
   1148   switch (type) {
   1149     case 0:
   1150       Shift = ARM_AM::lsl;
   1151       break;
   1152     case 1:
   1153       Shift = ARM_AM::lsr;
   1154       break;
   1155     case 2:
   1156       Shift = ARM_AM::asr;
   1157       break;
   1158     case 3:
   1159       Shift = ARM_AM::ror;
   1160       break;
   1161   }
   1162 
   1163   if (Shift == ARM_AM::ror && imm == 0)
   1164     Shift = ARM_AM::rrx;
   1165 
   1166   unsigned Op = Shift | (imm << 3);
   1167   Inst.addOperand(MCOperand::createImm(Op));
   1168 
   1169   return S;
   1170 }
   1171 
   1172 static DecodeStatus DecodeSORegRegOperand(MCInst &Inst, unsigned Val,
   1173                                uint64_t Address, const void *Decoder) {
   1174   DecodeStatus S = MCDisassembler::Success;
   1175 
   1176   unsigned Rm = fieldFromInstruction(Val, 0, 4);
   1177   unsigned type = fieldFromInstruction(Val, 5, 2);
   1178   unsigned Rs = fieldFromInstruction(Val, 8, 4);
   1179 
   1180   // Register-register
   1181   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
   1182     return MCDisassembler::Fail;
   1183   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
   1184     return MCDisassembler::Fail;
   1185 
   1186   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
   1187   switch (type) {
   1188     case 0:
   1189       Shift = ARM_AM::lsl;
   1190       break;
   1191     case 1:
   1192       Shift = ARM_AM::lsr;
   1193       break;
   1194     case 2:
   1195       Shift = ARM_AM::asr;
   1196       break;
   1197     case 3:
   1198       Shift = ARM_AM::ror;
   1199       break;
   1200   }
   1201 
   1202   Inst.addOperand(MCOperand::createImm(Shift));
   1203 
   1204   return S;
   1205 }
   1206 
   1207 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Val,
   1208                                  uint64_t Address, const void *Decoder) {
   1209   DecodeStatus S = MCDisassembler::Success;
   1210 
   1211   bool NeedDisjointWriteback = false;
   1212   unsigned WritebackReg = 0;
   1213   switch (Inst.getOpcode()) {
   1214   default:
   1215     break;
   1216   case ARM::LDMIA_UPD:
   1217   case ARM::LDMDB_UPD:
   1218   case ARM::LDMIB_UPD:
   1219   case ARM::LDMDA_UPD:
   1220   case ARM::t2LDMIA_UPD:
   1221   case ARM::t2LDMDB_UPD:
   1222   case ARM::t2STMIA_UPD:
   1223   case ARM::t2STMDB_UPD:
   1224     NeedDisjointWriteback = true;
   1225     WritebackReg = Inst.getOperand(0).getReg();
   1226     break;
   1227   }
   1228 
   1229   // Empty register lists are not allowed.
   1230   if (Val == 0) return MCDisassembler::Fail;
   1231   for (unsigned i = 0; i < 16; ++i) {
   1232     if (Val & (1 << i)) {
   1233       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
   1234         return MCDisassembler::Fail;
   1235       // Writeback not allowed if Rn is in the target list.
   1236       if (NeedDisjointWriteback && WritebackReg == Inst.end()[-1].getReg())
   1237         Check(S, MCDisassembler::SoftFail);
   1238     }
   1239   }
   1240 
   1241   return S;
   1242 }
   1243 
   1244 static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
   1245                                  uint64_t Address, const void *Decoder) {
   1246   DecodeStatus S = MCDisassembler::Success;
   1247 
   1248   unsigned Vd = fieldFromInstruction(Val, 8, 5);
   1249   unsigned regs = fieldFromInstruction(Val, 0, 8);
   1250 
   1251   // In case of unpredictable encoding, tweak the operands.
   1252   if (regs == 0 || (Vd + regs) > 32) {
   1253     regs = Vd + regs > 32 ? 32 - Vd : regs;
   1254     regs = std::max( 1u, regs);
   1255     S = MCDisassembler::SoftFail;
   1256   }
   1257 
   1258   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
   1259     return MCDisassembler::Fail;
   1260   for (unsigned i = 0; i < (regs - 1); ++i) {
   1261     if (!Check(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
   1262       return MCDisassembler::Fail;
   1263   }
   1264 
   1265   return S;
   1266 }
   1267 
   1268 static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
   1269                                  uint64_t Address, const void *Decoder) {
   1270   DecodeStatus S = MCDisassembler::Success;
   1271 
   1272   unsigned Vd = fieldFromInstruction(Val, 8, 5);
   1273   unsigned regs = fieldFromInstruction(Val, 1, 7);
   1274 
   1275   // In case of unpredictable encoding, tweak the operands.
   1276   if (regs == 0 || regs > 16 || (Vd + regs) > 32) {
   1277     regs = Vd + regs > 32 ? 32 - Vd : regs;
   1278     regs = std::max( 1u, regs);
   1279     regs = std::min(16u, regs);
   1280     S = MCDisassembler::SoftFail;
   1281   }
   1282 
   1283   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
   1284       return MCDisassembler::Fail;
   1285   for (unsigned i = 0; i < (regs - 1); ++i) {
   1286     if (!Check(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
   1287       return MCDisassembler::Fail;
   1288   }
   1289 
   1290   return S;
   1291 }
   1292 
   1293 static DecodeStatus DecodeBitfieldMaskOperand(MCInst &Inst, unsigned Val,
   1294                                       uint64_t Address, const void *Decoder) {
   1295   // This operand encodes a mask of contiguous zeros between a specified MSB
   1296   // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
   1297   // the mask of all bits LSB-and-lower, and then xor them to create
   1298   // the mask of that's all ones on [msb, lsb].  Finally we not it to
   1299   // create the final mask.
   1300   unsigned msb = fieldFromInstruction(Val, 5, 5);
   1301   unsigned lsb = fieldFromInstruction(Val, 0, 5);
   1302 
   1303   DecodeStatus S = MCDisassembler::Success;
   1304   if (lsb > msb) {
   1305     Check(S, MCDisassembler::SoftFail);
   1306     // The check above will cause the warning for the "potentially undefined
   1307     // instruction encoding" but we can't build a bad MCOperand value here
   1308     // with a lsb > msb or else printing the MCInst will cause a crash.
   1309     lsb = msb;
   1310   }
   1311 
   1312   uint32_t msb_mask = 0xFFFFFFFF;
   1313   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;
   1314   uint32_t lsb_mask = (1U << lsb) - 1;
   1315 
   1316   Inst.addOperand(MCOperand::createImm(~(msb_mask ^ lsb_mask)));
   1317   return S;
   1318 }
   1319 
   1320 static DecodeStatus DecodeCopMemInstruction(MCInst &Inst, unsigned Insn,
   1321                                   uint64_t Address, const void *Decoder) {
   1322   DecodeStatus S = MCDisassembler::Success;
   1323 
   1324   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   1325   unsigned CRd = fieldFromInstruction(Insn, 12, 4);
   1326   unsigned coproc = fieldFromInstruction(Insn, 8, 4);
   1327   unsigned imm = fieldFromInstruction(Insn, 0, 8);
   1328   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   1329   unsigned U = fieldFromInstruction(Insn, 23, 1);
   1330 
   1331   switch (Inst.getOpcode()) {
   1332     case ARM::LDC_OFFSET:
   1333     case ARM::LDC_PRE:
   1334     case ARM::LDC_POST:
   1335     case ARM::LDC_OPTION:
   1336     case ARM::LDCL_OFFSET:
   1337     case ARM::LDCL_PRE:
   1338     case ARM::LDCL_POST:
   1339     case ARM::LDCL_OPTION:
   1340     case ARM::STC_OFFSET:
   1341     case ARM::STC_PRE:
   1342     case ARM::STC_POST:
   1343     case ARM::STC_OPTION:
   1344     case ARM::STCL_OFFSET:
   1345     case ARM::STCL_PRE:
   1346     case ARM::STCL_POST:
   1347     case ARM::STCL_OPTION:
   1348     case ARM::t2LDC_OFFSET:
   1349     case ARM::t2LDC_PRE:
   1350     case ARM::t2LDC_POST:
   1351     case ARM::t2LDC_OPTION:
   1352     case ARM::t2LDCL_OFFSET:
   1353     case ARM::t2LDCL_PRE:
   1354     case ARM::t2LDCL_POST:
   1355     case ARM::t2LDCL_OPTION:
   1356     case ARM::t2STC_OFFSET:
   1357     case ARM::t2STC_PRE:
   1358     case ARM::t2STC_POST:
   1359     case ARM::t2STC_OPTION:
   1360     case ARM::t2STCL_OFFSET:
   1361     case ARM::t2STCL_PRE:
   1362     case ARM::t2STCL_POST:
   1363     case ARM::t2STCL_OPTION:
   1364       if (coproc == 0xA || coproc == 0xB)
   1365         return MCDisassembler::Fail;
   1366       break;
   1367     default:
   1368       break;
   1369   }
   1370 
   1371   const FeatureBitset &featureBits =
   1372     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
   1373   if (featureBits[ARM::HasV8Ops] && (coproc != 14))
   1374     return MCDisassembler::Fail;
   1375 
   1376   Inst.addOperand(MCOperand::createImm(coproc));
   1377   Inst.addOperand(MCOperand::createImm(CRd));
   1378   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   1379     return MCDisassembler::Fail;
   1380 
   1381   switch (Inst.getOpcode()) {
   1382     case ARM::t2LDC2_OFFSET:
   1383     case ARM::t2LDC2L_OFFSET:
   1384     case ARM::t2LDC2_PRE:
   1385     case ARM::t2LDC2L_PRE:
   1386     case ARM::t2STC2_OFFSET:
   1387     case ARM::t2STC2L_OFFSET:
   1388     case ARM::t2STC2_PRE:
   1389     case ARM::t2STC2L_PRE:
   1390     case ARM::LDC2_OFFSET:
   1391     case ARM::LDC2L_OFFSET:
   1392     case ARM::LDC2_PRE:
   1393     case ARM::LDC2L_PRE:
   1394     case ARM::STC2_OFFSET:
   1395     case ARM::STC2L_OFFSET:
   1396     case ARM::STC2_PRE:
   1397     case ARM::STC2L_PRE:
   1398     case ARM::t2LDC_OFFSET:
   1399     case ARM::t2LDCL_OFFSET:
   1400     case ARM::t2LDC_PRE:
   1401     case ARM::t2LDCL_PRE:
   1402     case ARM::t2STC_OFFSET:
   1403     case ARM::t2STCL_OFFSET:
   1404     case ARM::t2STC_PRE:
   1405     case ARM::t2STCL_PRE:
   1406     case ARM::LDC_OFFSET:
   1407     case ARM::LDCL_OFFSET:
   1408     case ARM::LDC_PRE:
   1409     case ARM::LDCL_PRE:
   1410     case ARM::STC_OFFSET:
   1411     case ARM::STCL_OFFSET:
   1412     case ARM::STC_PRE:
   1413     case ARM::STCL_PRE:
   1414       imm = ARM_AM::getAM5Opc(U ? ARM_AM::add : ARM_AM::sub, imm);
   1415       Inst.addOperand(MCOperand::createImm(imm));
   1416       break;
   1417     case ARM::t2LDC2_POST:
   1418     case ARM::t2LDC2L_POST:
   1419     case ARM::t2STC2_POST:
   1420     case ARM::t2STC2L_POST:
   1421     case ARM::LDC2_POST:
   1422     case ARM::LDC2L_POST:
   1423     case ARM::STC2_POST:
   1424     case ARM::STC2L_POST:
   1425     case ARM::t2LDC_POST:
   1426     case ARM::t2LDCL_POST:
   1427     case ARM::t2STC_POST:
   1428     case ARM::t2STCL_POST:
   1429     case ARM::LDC_POST:
   1430     case ARM::LDCL_POST:
   1431     case ARM::STC_POST:
   1432     case ARM::STCL_POST:
   1433       imm |= U << 8;
   1434       LLVM_FALLTHROUGH;
   1435     default:
   1436       // The 'option' variant doesn't encode 'U' in the immediate since
   1437       // the immediate is unsigned [0,255].
   1438       Inst.addOperand(MCOperand::createImm(imm));
   1439       break;
   1440   }
   1441 
   1442   switch (Inst.getOpcode()) {
   1443     case ARM::LDC_OFFSET:
   1444     case ARM::LDC_PRE:
   1445     case ARM::LDC_POST:
   1446     case ARM::LDC_OPTION:
   1447     case ARM::LDCL_OFFSET:
   1448     case ARM::LDCL_PRE:
   1449     case ARM::LDCL_POST:
   1450     case ARM::LDCL_OPTION:
   1451     case ARM::STC_OFFSET:
   1452     case ARM::STC_PRE:
   1453     case ARM::STC_POST:
   1454     case ARM::STC_OPTION:
   1455     case ARM::STCL_OFFSET:
   1456     case ARM::STCL_PRE:
   1457     case ARM::STCL_POST:
   1458     case ARM::STCL_OPTION:
   1459       if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   1460         return MCDisassembler::Fail;
   1461       break;
   1462     default:
   1463       break;
   1464   }
   1465 
   1466   return S;
   1467 }
   1468 
   1469 static DecodeStatus
   1470 DecodeAddrMode2IdxInstruction(MCInst &Inst, unsigned Insn,
   1471                               uint64_t Address, const void *Decoder) {
   1472   DecodeStatus S = MCDisassembler::Success;
   1473 
   1474   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   1475   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   1476   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   1477   unsigned imm = fieldFromInstruction(Insn, 0, 12);
   1478   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   1479   unsigned reg = fieldFromInstruction(Insn, 25, 1);
   1480   unsigned P = fieldFromInstruction(Insn, 24, 1);
   1481   unsigned W = fieldFromInstruction(Insn, 21, 1);
   1482 
   1483   // On stores, the writeback operand precedes Rt.
   1484   switch (Inst.getOpcode()) {
   1485     case ARM::STR_POST_IMM:
   1486     case ARM::STR_POST_REG:
   1487     case ARM::STRB_POST_IMM:
   1488     case ARM::STRB_POST_REG:
   1489     case ARM::STRT_POST_REG:
   1490     case ARM::STRT_POST_IMM:
   1491     case ARM::STRBT_POST_REG:
   1492     case ARM::STRBT_POST_IMM:
   1493       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   1494         return MCDisassembler::Fail;
   1495       break;
   1496     default:
   1497       break;
   1498   }
   1499 
   1500   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
   1501     return MCDisassembler::Fail;
   1502 
   1503   // On loads, the writeback operand comes after Rt.
   1504   switch (Inst.getOpcode()) {
   1505     case ARM::LDR_POST_IMM:
   1506     case ARM::LDR_POST_REG:
   1507     case ARM::LDRB_POST_IMM:
   1508     case ARM::LDRB_POST_REG:
   1509     case ARM::LDRBT_POST_REG:
   1510     case ARM::LDRBT_POST_IMM:
   1511     case ARM::LDRT_POST_REG:
   1512     case ARM::LDRT_POST_IMM:
   1513       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   1514         return MCDisassembler::Fail;
   1515       break;
   1516     default:
   1517       break;
   1518   }
   1519 
   1520   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   1521     return MCDisassembler::Fail;
   1522 
   1523   ARM_AM::AddrOpc Op = ARM_AM::add;
   1524   if (!fieldFromInstruction(Insn, 23, 1))
   1525     Op = ARM_AM::sub;
   1526 
   1527   bool writeback = (P == 0) || (W == 1);
   1528   unsigned idx_mode = 0;
   1529   if (P && writeback)
   1530     idx_mode = ARMII::IndexModePre;
   1531   else if (!P && writeback)
   1532     idx_mode = ARMII::IndexModePost;
   1533 
   1534   if (writeback && (Rn == 15 || Rn == Rt))
   1535     S = MCDisassembler::SoftFail; // UNPREDICTABLE
   1536 
   1537   if (reg) {
   1538     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
   1539       return MCDisassembler::Fail;
   1540     ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
   1541     switch( fieldFromInstruction(Insn, 5, 2)) {
   1542       case 0:
   1543         Opc = ARM_AM::lsl;
   1544         break;
   1545       case 1:
   1546         Opc = ARM_AM::lsr;
   1547         break;
   1548       case 2:
   1549         Opc = ARM_AM::asr;
   1550         break;
   1551       case 3:
   1552         Opc = ARM_AM::ror;
   1553         break;
   1554       default:
   1555         return MCDisassembler::Fail;
   1556     }
   1557     unsigned amt = fieldFromInstruction(Insn, 7, 5);
   1558     if (Opc == ARM_AM::ror && amt == 0)
   1559       Opc = ARM_AM::rrx;
   1560     unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
   1561 
   1562     Inst.addOperand(MCOperand::createImm(imm));
   1563   } else {
   1564     Inst.addOperand(MCOperand::createReg(0));
   1565     unsigned tmp = ARM_AM::getAM2Opc(Op, imm, ARM_AM::lsl, idx_mode);
   1566     Inst.addOperand(MCOperand::createImm(tmp));
   1567   }
   1568 
   1569   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   1570     return MCDisassembler::Fail;
   1571 
   1572   return S;
   1573 }
   1574 
   1575 static DecodeStatus DecodeSORegMemOperand(MCInst &Inst, unsigned Val,
   1576                                   uint64_t Address, const void *Decoder) {
   1577   DecodeStatus S = MCDisassembler::Success;
   1578 
   1579   unsigned Rn = fieldFromInstruction(Val, 13, 4);
   1580   unsigned Rm = fieldFromInstruction(Val,  0, 4);
   1581   unsigned type = fieldFromInstruction(Val, 5, 2);
   1582   unsigned imm = fieldFromInstruction(Val, 7, 5);
   1583   unsigned U = fieldFromInstruction(Val, 12, 1);
   1584 
   1585   ARM_AM::ShiftOpc ShOp = ARM_AM::lsl;
   1586   switch (type) {
   1587     case 0:
   1588       ShOp = ARM_AM::lsl;
   1589       break;
   1590     case 1:
   1591       ShOp = ARM_AM::lsr;
   1592       break;
   1593     case 2:
   1594       ShOp = ARM_AM::asr;
   1595       break;
   1596     case 3:
   1597       ShOp = ARM_AM::ror;
   1598       break;
   1599   }
   1600 
   1601   if (ShOp == ARM_AM::ror && imm == 0)
   1602     ShOp = ARM_AM::rrx;
   1603 
   1604   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   1605     return MCDisassembler::Fail;
   1606   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   1607     return MCDisassembler::Fail;
   1608   unsigned shift;
   1609   if (U)
   1610     shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
   1611   else
   1612     shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
   1613   Inst.addOperand(MCOperand::createImm(shift));
   1614 
   1615   return S;
   1616 }
   1617 
   1618 static DecodeStatus
   1619 DecodeAddrMode3Instruction(MCInst &Inst, unsigned Insn,
   1620                            uint64_t Address, const void *Decoder) {
   1621   DecodeStatus S = MCDisassembler::Success;
   1622 
   1623   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   1624   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   1625   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   1626   unsigned type = fieldFromInstruction(Insn, 22, 1);
   1627   unsigned imm = fieldFromInstruction(Insn, 8, 4);
   1628   unsigned U = ((~fieldFromInstruction(Insn, 23, 1)) & 1) << 8;
   1629   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   1630   unsigned W = fieldFromInstruction(Insn, 21, 1);
   1631   unsigned P = fieldFromInstruction(Insn, 24, 1);
   1632   unsigned Rt2 = Rt + 1;
   1633 
   1634   bool writeback = (W == 1) | (P == 0);
   1635 
   1636   // For {LD,ST}RD, Rt must be even, else undefined.
   1637   switch (Inst.getOpcode()) {
   1638     case ARM::STRD:
   1639     case ARM::STRD_PRE:
   1640     case ARM::STRD_POST:
   1641     case ARM::LDRD:
   1642     case ARM::LDRD_PRE:
   1643     case ARM::LDRD_POST:
   1644       if (Rt & 0x1) S = MCDisassembler::SoftFail;
   1645       break;
   1646     default:
   1647       break;
   1648   }
   1649   switch (Inst.getOpcode()) {
   1650     case ARM::STRD:
   1651     case ARM::STRD_PRE:
   1652     case ARM::STRD_POST:
   1653       if (P == 0 && W == 1)
   1654         S = MCDisassembler::SoftFail;
   1655 
   1656       if (writeback && (Rn == 15 || Rn == Rt || Rn == Rt2))
   1657         S = MCDisassembler::SoftFail;
   1658       if (type && Rm == 15)
   1659         S = MCDisassembler::SoftFail;
   1660       if (Rt2 == 15)
   1661         S = MCDisassembler::SoftFail;
   1662       if (!type && fieldFromInstruction(Insn, 8, 4))
   1663         S = MCDisassembler::SoftFail;
   1664       break;
   1665     case ARM::STRH:
   1666     case ARM::STRH_PRE:
   1667     case ARM::STRH_POST:
   1668       if (Rt == 15)
   1669         S = MCDisassembler::SoftFail;
   1670       if (writeback && (Rn == 15 || Rn == Rt))
   1671         S = MCDisassembler::SoftFail;
   1672       if (!type && Rm == 15)
   1673         S = MCDisassembler::SoftFail;
   1674       break;
   1675     case ARM::LDRD:
   1676     case ARM::LDRD_PRE:
   1677     case ARM::LDRD_POST:
   1678       if (type && Rn == 15) {
   1679         if (Rt2 == 15)
   1680           S = MCDisassembler::SoftFail;
   1681         break;
   1682       }
   1683       if (P == 0 && W == 1)
   1684         S = MCDisassembler::SoftFail;
   1685       if (!type && (Rt2 == 15 || Rm == 15 || Rm == Rt || Rm == Rt2))
   1686         S = MCDisassembler::SoftFail;
   1687       if (!type && writeback && Rn == 15)
   1688         S = MCDisassembler::SoftFail;
   1689       if (writeback && (Rn == Rt || Rn == Rt2))
   1690         S = MCDisassembler::SoftFail;
   1691       break;
   1692     case ARM::LDRH:
   1693     case ARM::LDRH_PRE:
   1694     case ARM::LDRH_POST:
   1695       if (type && Rn == 15) {
   1696         if (Rt == 15)
   1697           S = MCDisassembler::SoftFail;
   1698         break;
   1699       }
   1700       if (Rt == 15)
   1701         S = MCDisassembler::SoftFail;
   1702       if (!type && Rm == 15)
   1703         S = MCDisassembler::SoftFail;
   1704       if (!type && writeback && (Rn == 15 || Rn == Rt))
   1705         S = MCDisassembler::SoftFail;
   1706       break;
   1707     case ARM::LDRSH:
   1708     case ARM::LDRSH_PRE:
   1709     case ARM::LDRSH_POST:
   1710     case ARM::LDRSB:
   1711     case ARM::LDRSB_PRE:
   1712     case ARM::LDRSB_POST:
   1713       if (type && Rn == 15) {
   1714         if (Rt == 15)
   1715           S = MCDisassembler::SoftFail;
   1716         break;
   1717       }
   1718       if (type && (Rt == 15 || (writeback && Rn == Rt)))
   1719         S = MCDisassembler::SoftFail;
   1720       if (!type && (Rt == 15 || Rm == 15))
   1721         S = MCDisassembler::SoftFail;
   1722       if (!type && writeback && (Rn == 15 || Rn == Rt))
   1723         S = MCDisassembler::SoftFail;
   1724       break;
   1725     default:
   1726       break;
   1727   }
   1728 
   1729   if (writeback) { // Writeback
   1730     if (P)
   1731       U |= ARMII::IndexModePre << 9;
   1732     else
   1733       U |= ARMII::IndexModePost << 9;
   1734 
   1735     // On stores, the writeback operand precedes Rt.
   1736     switch (Inst.getOpcode()) {
   1737     case ARM::STRD:
   1738     case ARM::STRD_PRE:
   1739     case ARM::STRD_POST:
   1740     case ARM::STRH:
   1741     case ARM::STRH_PRE:
   1742     case ARM::STRH_POST:
   1743       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   1744         return MCDisassembler::Fail;
   1745       break;
   1746     default:
   1747       break;
   1748     }
   1749   }
   1750 
   1751   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
   1752     return MCDisassembler::Fail;
   1753   switch (Inst.getOpcode()) {
   1754     case ARM::STRD:
   1755     case ARM::STRD_PRE:
   1756     case ARM::STRD_POST:
   1757     case ARM::LDRD:
   1758     case ARM::LDRD_PRE:
   1759     case ARM::LDRD_POST:
   1760       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)))
   1761         return MCDisassembler::Fail;
   1762       break;
   1763     default:
   1764       break;
   1765   }
   1766 
   1767   if (writeback) {
   1768     // On loads, the writeback operand comes after Rt.
   1769     switch (Inst.getOpcode()) {
   1770     case ARM::LDRD:
   1771     case ARM::LDRD_PRE:
   1772     case ARM::LDRD_POST:
   1773     case ARM::LDRH:
   1774     case ARM::LDRH_PRE:
   1775     case ARM::LDRH_POST:
   1776     case ARM::LDRSH:
   1777     case ARM::LDRSH_PRE:
   1778     case ARM::LDRSH_POST:
   1779     case ARM::LDRSB:
   1780     case ARM::LDRSB_PRE:
   1781     case ARM::LDRSB_POST:
   1782     case ARM::LDRHTr:
   1783     case ARM::LDRSBTr:
   1784       if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   1785         return MCDisassembler::Fail;
   1786       break;
   1787     default:
   1788       break;
   1789     }
   1790   }
   1791 
   1792   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   1793     return MCDisassembler::Fail;
   1794 
   1795   if (type) {
   1796     Inst.addOperand(MCOperand::createReg(0));
   1797     Inst.addOperand(MCOperand::createImm(U | (imm << 4) | Rm));
   1798   } else {
   1799     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   1800     return MCDisassembler::Fail;
   1801     Inst.addOperand(MCOperand::createImm(U));
   1802   }
   1803 
   1804   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   1805     return MCDisassembler::Fail;
   1806 
   1807   return S;
   1808 }
   1809 
   1810 static DecodeStatus DecodeRFEInstruction(MCInst &Inst, unsigned Insn,
   1811                                  uint64_t Address, const void *Decoder) {
   1812   DecodeStatus S = MCDisassembler::Success;
   1813 
   1814   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   1815   unsigned mode = fieldFromInstruction(Insn, 23, 2);
   1816 
   1817   switch (mode) {
   1818     case 0:
   1819       mode = ARM_AM::da;
   1820       break;
   1821     case 1:
   1822       mode = ARM_AM::ia;
   1823       break;
   1824     case 2:
   1825       mode = ARM_AM::db;
   1826       break;
   1827     case 3:
   1828       mode = ARM_AM::ib;
   1829       break;
   1830   }
   1831 
   1832   Inst.addOperand(MCOperand::createImm(mode));
   1833   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   1834     return MCDisassembler::Fail;
   1835 
   1836   return S;
   1837 }
   1838 
   1839 static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
   1840                                uint64_t Address, const void *Decoder) {
   1841   DecodeStatus S = MCDisassembler::Success;
   1842 
   1843   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   1844   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   1845   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   1846   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   1847 
   1848   if (pred == 0xF)
   1849     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
   1850 
   1851   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
   1852     return MCDisassembler::Fail;
   1853   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
   1854     return MCDisassembler::Fail;
   1855   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
   1856     return MCDisassembler::Fail;
   1857   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   1858     return MCDisassembler::Fail;
   1859   return S;
   1860 }
   1861 
   1862 static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst &Inst,
   1863                                   unsigned Insn,
   1864                                   uint64_t Address, const void *Decoder) {
   1865   DecodeStatus S = MCDisassembler::Success;
   1866 
   1867   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   1868   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   1869   unsigned reglist = fieldFromInstruction(Insn, 0, 16);
   1870 
   1871   if (pred == 0xF) {
   1872     // Ambiguous with RFE and SRS
   1873     switch (Inst.getOpcode()) {
   1874       case ARM::LDMDA:
   1875         Inst.setOpcode(ARM::RFEDA);
   1876         break;
   1877       case ARM::LDMDA_UPD:
   1878         Inst.setOpcode(ARM::RFEDA_UPD);
   1879         break;
   1880       case ARM::LDMDB:
   1881         Inst.setOpcode(ARM::RFEDB);
   1882         break;
   1883       case ARM::LDMDB_UPD:
   1884         Inst.setOpcode(ARM::RFEDB_UPD);
   1885         break;
   1886       case ARM::LDMIA:
   1887         Inst.setOpcode(ARM::RFEIA);
   1888         break;
   1889       case ARM::LDMIA_UPD:
   1890         Inst.setOpcode(ARM::RFEIA_UPD);
   1891         break;
   1892       case ARM::LDMIB:
   1893         Inst.setOpcode(ARM::RFEIB);
   1894         break;
   1895       case ARM::LDMIB_UPD:
   1896         Inst.setOpcode(ARM::RFEIB_UPD);
   1897         break;
   1898       case ARM::STMDA:
   1899         Inst.setOpcode(ARM::SRSDA);
   1900         break;
   1901       case ARM::STMDA_UPD:
   1902         Inst.setOpcode(ARM::SRSDA_UPD);
   1903         break;
   1904       case ARM::STMDB:
   1905         Inst.setOpcode(ARM::SRSDB);
   1906         break;
   1907       case ARM::STMDB_UPD:
   1908         Inst.setOpcode(ARM::SRSDB_UPD);
   1909         break;
   1910       case ARM::STMIA:
   1911         Inst.setOpcode(ARM::SRSIA);
   1912         break;
   1913       case ARM::STMIA_UPD:
   1914         Inst.setOpcode(ARM::SRSIA_UPD);
   1915         break;
   1916       case ARM::STMIB:
   1917         Inst.setOpcode(ARM::SRSIB);
   1918         break;
   1919       case ARM::STMIB_UPD:
   1920         Inst.setOpcode(ARM::SRSIB_UPD);
   1921         break;
   1922       default:
   1923         return MCDisassembler::Fail;
   1924     }
   1925 
   1926     // For stores (which become SRS's, the only operand is the mode.
   1927     if (fieldFromInstruction(Insn, 20, 1) == 0) {
   1928       // Check SRS encoding constraints
   1929       if (!(fieldFromInstruction(Insn, 22, 1) == 1 &&
   1930             fieldFromInstruction(Insn, 20, 1) == 0))
   1931         return MCDisassembler::Fail;
   1932 
   1933       Inst.addOperand(
   1934           MCOperand::createImm(fieldFromInstruction(Insn, 0, 4)));
   1935       return S;
   1936     }
   1937 
   1938     return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
   1939   }
   1940 
   1941   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   1942     return MCDisassembler::Fail;
   1943   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   1944     return MCDisassembler::Fail; // Tied
   1945   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   1946     return MCDisassembler::Fail;
   1947   if (!Check(S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
   1948     return MCDisassembler::Fail;
   1949 
   1950   return S;
   1951 }
   1952 
   1953 // Check for UNPREDICTABLE predicated ESB instruction
   1954 static DecodeStatus DecodeHINTInstruction(MCInst &Inst, unsigned Insn,
   1955                                  uint64_t Address, const void *Decoder) {
   1956   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   1957   unsigned imm8 = fieldFromInstruction(Insn, 0, 8);
   1958   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
   1959   const FeatureBitset &FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
   1960 
   1961   DecodeStatus S = MCDisassembler::Success;
   1962 
   1963   Inst.addOperand(MCOperand::createImm(imm8));
   1964 
   1965   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   1966     return MCDisassembler::Fail;
   1967 
   1968   // ESB is unpredictable if pred != AL. Without the RAS extension, it is a NOP,
   1969   // so all predicates should be allowed.
   1970   if (imm8 == 0x10 && pred != 0xe && ((FeatureBits[ARM::FeatureRAS]) != 0))
   1971     S = MCDisassembler::SoftFail;
   1972 
   1973   return S;
   1974 }
   1975 
   1976 static DecodeStatus DecodeCPSInstruction(MCInst &Inst, unsigned Insn,
   1977                                  uint64_t Address, const void *Decoder) {
   1978   unsigned imod = fieldFromInstruction(Insn, 18, 2);
   1979   unsigned M = fieldFromInstruction(Insn, 17, 1);
   1980   unsigned iflags = fieldFromInstruction(Insn, 6, 3);
   1981   unsigned mode = fieldFromInstruction(Insn, 0, 5);
   1982 
   1983   DecodeStatus S = MCDisassembler::Success;
   1984 
   1985   // This decoder is called from multiple location that do not check
   1986   // the full encoding is valid before they do.
   1987   if (fieldFromInstruction(Insn, 5, 1) != 0 ||
   1988       fieldFromInstruction(Insn, 16, 1) != 0 ||
   1989       fieldFromInstruction(Insn, 20, 8) != 0x10)
   1990     return MCDisassembler::Fail;
   1991 
   1992   // imod == '01' --> UNPREDICTABLE
   1993   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
   1994   // return failure here.  The '01' imod value is unprintable, so there's
   1995   // nothing useful we could do even if we returned UNPREDICTABLE.
   1996 
   1997   if (imod == 1) return MCDisassembler::Fail;
   1998 
   1999   if (imod && M) {
   2000     Inst.setOpcode(ARM::CPS3p);
   2001     Inst.addOperand(MCOperand::createImm(imod));
   2002     Inst.addOperand(MCOperand::createImm(iflags));
   2003     Inst.addOperand(MCOperand::createImm(mode));
   2004   } else if (imod && !M) {
   2005     Inst.setOpcode(ARM::CPS2p);
   2006     Inst.addOperand(MCOperand::createImm(imod));
   2007     Inst.addOperand(MCOperand::createImm(iflags));
   2008     if (mode) S = MCDisassembler::SoftFail;
   2009   } else if (!imod && M) {
   2010     Inst.setOpcode(ARM::CPS1p);
   2011     Inst.addOperand(MCOperand::createImm(mode));
   2012     if (iflags) S = MCDisassembler::SoftFail;
   2013   } else {
   2014     // imod == '00' && M == '0' --> UNPREDICTABLE
   2015     Inst.setOpcode(ARM::CPS1p);
   2016     Inst.addOperand(MCOperand::createImm(mode));
   2017     S = MCDisassembler::SoftFail;
   2018   }
   2019 
   2020   return S;
   2021 }
   2022 
   2023 static DecodeStatus DecodeT2CPSInstruction(MCInst &Inst, unsigned Insn,
   2024                                  uint64_t Address, const void *Decoder) {
   2025   unsigned imod = fieldFromInstruction(Insn, 9, 2);
   2026   unsigned M = fieldFromInstruction(Insn, 8, 1);
   2027   unsigned iflags = fieldFromInstruction(Insn, 5, 3);
   2028   unsigned mode = fieldFromInstruction(Insn, 0, 5);
   2029 
   2030   DecodeStatus S = MCDisassembler::Success;
   2031 
   2032   // imod == '01' --> UNPREDICTABLE
   2033   // NOTE: Even though this is technically UNPREDICTABLE, we choose to
   2034   // return failure here.  The '01' imod value is unprintable, so there's
   2035   // nothing useful we could do even if we returned UNPREDICTABLE.
   2036 
   2037   if (imod == 1) return MCDisassembler::Fail;
   2038 
   2039   if (imod && M) {
   2040     Inst.setOpcode(ARM::t2CPS3p);
   2041     Inst.addOperand(MCOperand::createImm(imod));
   2042     Inst.addOperand(MCOperand::createImm(iflags));
   2043     Inst.addOperand(MCOperand::createImm(mode));
   2044   } else if (imod && !M) {
   2045     Inst.setOpcode(ARM::t2CPS2p);
   2046     Inst.addOperand(MCOperand::createImm(imod));
   2047     Inst.addOperand(MCOperand::createImm(iflags));
   2048     if (mode) S = MCDisassembler::SoftFail;
   2049   } else if (!imod && M) {
   2050     Inst.setOpcode(ARM::t2CPS1p);
   2051     Inst.addOperand(MCOperand::createImm(mode));
   2052     if (iflags) S = MCDisassembler::SoftFail;
   2053   } else {
   2054     // imod == '00' && M == '0' --> this is a HINT instruction
   2055     int imm = fieldFromInstruction(Insn, 0, 8);
   2056     // HINT are defined only for immediate in [0..4]
   2057     if(imm > 4) return MCDisassembler::Fail;
   2058     Inst.setOpcode(ARM::t2HINT);
   2059     Inst.addOperand(MCOperand::createImm(imm));
   2060   }
   2061 
   2062   return S;
   2063 }
   2064 
   2065 static DecodeStatus DecodeT2MOVTWInstruction(MCInst &Inst, unsigned Insn,
   2066                                  uint64_t Address, const void *Decoder) {
   2067   DecodeStatus S = MCDisassembler::Success;
   2068 
   2069   unsigned Rd = fieldFromInstruction(Insn, 8, 4);
   2070   unsigned imm = 0;
   2071 
   2072   imm |= (fieldFromInstruction(Insn, 0, 8) << 0);
   2073   imm |= (fieldFromInstruction(Insn, 12, 3) << 8);
   2074   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
   2075   imm |= (fieldFromInstruction(Insn, 26, 1) << 11);
   2076 
   2077   if (Inst.getOpcode() == ARM::t2MOVTi16)
   2078     if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
   2079       return MCDisassembler::Fail;
   2080   if (!Check(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
   2081     return MCDisassembler::Fail;
   2082 
   2083   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
   2084     Inst.addOperand(MCOperand::createImm(imm));
   2085 
   2086   return S;
   2087 }
   2088 
   2089 static DecodeStatus DecodeArmMOVTWInstruction(MCInst &Inst, unsigned Insn,
   2090                                  uint64_t Address, const void *Decoder) {
   2091   DecodeStatus S = MCDisassembler::Success;
   2092 
   2093   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   2094   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   2095   unsigned imm = 0;
   2096 
   2097   imm |= (fieldFromInstruction(Insn, 0, 12) << 0);
   2098   imm |= (fieldFromInstruction(Insn, 16, 4) << 12);
   2099 
   2100   if (Inst.getOpcode() == ARM::MOVTi16)
   2101     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
   2102       return MCDisassembler::Fail;
   2103 
   2104   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
   2105     return MCDisassembler::Fail;
   2106 
   2107   if (!tryAddingSymbolicOperand(Address, imm, false, 4, Inst, Decoder))
   2108     Inst.addOperand(MCOperand::createImm(imm));
   2109 
   2110   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   2111     return MCDisassembler::Fail;
   2112 
   2113   return S;
   2114 }
   2115 
   2116 static DecodeStatus DecodeSMLAInstruction(MCInst &Inst, unsigned Insn,
   2117                                  uint64_t Address, const void *Decoder) {
   2118   DecodeStatus S = MCDisassembler::Success;
   2119 
   2120   unsigned Rd = fieldFromInstruction(Insn, 16, 4);
   2121   unsigned Rn = fieldFromInstruction(Insn, 0, 4);
   2122   unsigned Rm = fieldFromInstruction(Insn, 8, 4);
   2123   unsigned Ra = fieldFromInstruction(Insn, 12, 4);
   2124   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   2125 
   2126   if (pred == 0xF)
   2127     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
   2128 
   2129   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
   2130     return MCDisassembler::Fail;
   2131   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
   2132     return MCDisassembler::Fail;
   2133   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
   2134     return MCDisassembler::Fail;
   2135   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
   2136     return MCDisassembler::Fail;
   2137 
   2138   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   2139     return MCDisassembler::Fail;
   2140 
   2141   return S;
   2142 }
   2143 
   2144 static DecodeStatus DecodeTSTInstruction(MCInst &Inst, unsigned Insn,
   2145                                   uint64_t Address, const void *Decoder) {
   2146   DecodeStatus S = MCDisassembler::Success;
   2147 
   2148   unsigned Pred = fieldFromInstruction(Insn, 28, 4);
   2149   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   2150   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   2151 
   2152   if (Pred == 0xF)
   2153     return DecodeSETPANInstruction(Inst, Insn, Address, Decoder);
   2154 
   2155   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   2156     return MCDisassembler::Fail;
   2157   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   2158     return MCDisassembler::Fail;
   2159   if (!Check(S, DecodePredicateOperand(Inst, Pred, Address, Decoder)))
   2160     return MCDisassembler::Fail;
   2161 
   2162   return S;
   2163 }
   2164 
   2165 static DecodeStatus DecodeSETPANInstruction(MCInst &Inst, unsigned Insn,
   2166                                   uint64_t Address, const void *Decoder) {
   2167   DecodeStatus S = MCDisassembler::Success;
   2168 
   2169   unsigned Imm = fieldFromInstruction(Insn, 9, 1);
   2170 
   2171   const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder);
   2172   const FeatureBitset &FeatureBits = Dis->getSubtargetInfo().getFeatureBits();
   2173 
   2174   if (!FeatureBits[ARM::HasV8_1aOps] ||
   2175       !FeatureBits[ARM::HasV8Ops])
   2176     return MCDisassembler::Fail;
   2177 
   2178   // Decoder can be called from DecodeTST, which does not check the full
   2179   // encoding is valid.
   2180   if (fieldFromInstruction(Insn, 20,12) != 0xf11 ||
   2181       fieldFromInstruction(Insn, 4,4) != 0)
   2182     return MCDisassembler::Fail;
   2183   if (fieldFromInstruction(Insn, 10,10) != 0 ||
   2184       fieldFromInstruction(Insn, 0,4) != 0)
   2185     S = MCDisassembler::SoftFail;
   2186 
   2187   Inst.setOpcode(ARM::SETPAN);
   2188   Inst.addOperand(MCOperand::createImm(Imm));
   2189 
   2190   return S;
   2191 }
   2192 
   2193 static DecodeStatus DecodeAddrModeImm12Operand(MCInst &Inst, unsigned Val,
   2194                            uint64_t Address, const void *Decoder) {
   2195   DecodeStatus S = MCDisassembler::Success;
   2196 
   2197   unsigned add = fieldFromInstruction(Val, 12, 1);
   2198   unsigned imm = fieldFromInstruction(Val, 0, 12);
   2199   unsigned Rn = fieldFromInstruction(Val, 13, 4);
   2200 
   2201   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   2202     return MCDisassembler::Fail;
   2203 
   2204   if (!add) imm *= -1;
   2205   if (imm == 0 && !add) imm = INT32_MIN;
   2206   Inst.addOperand(MCOperand::createImm(imm));
   2207   if (Rn == 15)
   2208     tryAddingPcLoadReferenceComment(Address, Address + imm + 8, Decoder);
   2209 
   2210   return S;
   2211 }
   2212 
   2213 static DecodeStatus DecodeAddrMode5Operand(MCInst &Inst, unsigned Val,
   2214                                    uint64_t Address, const void *Decoder) {
   2215   DecodeStatus S = MCDisassembler::Success;
   2216 
   2217   unsigned Rn = fieldFromInstruction(Val, 9, 4);
   2218   // U == 1 to add imm, 0 to subtract it.
   2219   unsigned U = fieldFromInstruction(Val, 8, 1);
   2220   unsigned imm = fieldFromInstruction(Val, 0, 8);
   2221 
   2222   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   2223     return MCDisassembler::Fail;
   2224 
   2225   if (U)
   2226     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5Opc(ARM_AM::add, imm)));
   2227   else
   2228     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5Opc(ARM_AM::sub, imm)));
   2229 
   2230   return S;
   2231 }
   2232 
   2233 static DecodeStatus DecodeAddrMode5FP16Operand(MCInst &Inst, unsigned Val,
   2234                                    uint64_t Address, const void *Decoder) {
   2235   DecodeStatus S = MCDisassembler::Success;
   2236 
   2237   unsigned Rn = fieldFromInstruction(Val, 9, 4);
   2238   // U == 1 to add imm, 0 to subtract it.
   2239   unsigned U = fieldFromInstruction(Val, 8, 1);
   2240   unsigned imm = fieldFromInstruction(Val, 0, 8);
   2241 
   2242   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   2243     return MCDisassembler::Fail;
   2244 
   2245   if (U)
   2246     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5FP16Opc(ARM_AM::add, imm)));
   2247   else
   2248     Inst.addOperand(MCOperand::createImm(ARM_AM::getAM5FP16Opc(ARM_AM::sub, imm)));
   2249 
   2250   return S;
   2251 }
   2252 
   2253 static DecodeStatus DecodeAddrMode7Operand(MCInst &Inst, unsigned Val,
   2254                                    uint64_t Address, const void *Decoder) {
   2255   return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
   2256 }
   2257 
   2258 static DecodeStatus
   2259 DecodeT2BInstruction(MCInst &Inst, unsigned Insn,
   2260                      uint64_t Address, const void *Decoder) {
   2261   DecodeStatus Status = MCDisassembler::Success;
   2262 
   2263   // Note the J1 and J2 values are from the encoded instruction.  So here
   2264   // change them to I1 and I2 values via as documented:
   2265   // I1 = NOT(J1 EOR S);
   2266   // I2 = NOT(J2 EOR S);
   2267   // and build the imm32 with one trailing zero as documented:
   2268   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
   2269   unsigned S = fieldFromInstruction(Insn, 26, 1);
   2270   unsigned J1 = fieldFromInstruction(Insn, 13, 1);
   2271   unsigned J2 = fieldFromInstruction(Insn, 11, 1);
   2272   unsigned I1 = !(J1 ^ S);
   2273   unsigned I2 = !(J2 ^ S);
   2274   unsigned imm10 = fieldFromInstruction(Insn, 16, 10);
   2275   unsigned imm11 = fieldFromInstruction(Insn, 0, 11);
   2276   unsigned tmp = (S << 23) | (I1 << 22) | (I2 << 21) | (imm10 << 11) | imm11;
   2277   int imm32 = SignExtend32<25>(tmp << 1);
   2278   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
   2279                                 true, 4, Inst, Decoder))
   2280     Inst.addOperand(MCOperand::createImm(imm32));
   2281 
   2282   return Status;
   2283 }
   2284 
   2285 static DecodeStatus
   2286 DecodeBranchImmInstruction(MCInst &Inst, unsigned Insn,
   2287                            uint64_t Address, const void *Decoder) {
   2288   DecodeStatus S = MCDisassembler::Success;
   2289 
   2290   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   2291   unsigned imm = fieldFromInstruction(Insn, 0, 24) << 2;
   2292 
   2293   if (pred == 0xF) {
   2294     Inst.setOpcode(ARM::BLXi);
   2295     imm |= fieldFromInstruction(Insn, 24, 1) << 1;
   2296     if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
   2297                                   true, 4, Inst, Decoder))
   2298     Inst.addOperand(MCOperand::createImm(SignExtend32<26>(imm)));
   2299     return S;
   2300   }
   2301 
   2302   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<26>(imm) + 8,
   2303                                 true, 4, Inst, Decoder))
   2304     Inst.addOperand(MCOperand::createImm(SignExtend32<26>(imm)));
   2305   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   2306     return MCDisassembler::Fail;
   2307 
   2308   return S;
   2309 }
   2310 
   2311 static DecodeStatus DecodeAddrMode6Operand(MCInst &Inst, unsigned Val,
   2312                                    uint64_t Address, const void *Decoder) {
   2313   DecodeStatus S = MCDisassembler::Success;
   2314 
   2315   unsigned Rm = fieldFromInstruction(Val, 0, 4);
   2316   unsigned align = fieldFromInstruction(Val, 4, 2);
   2317 
   2318   if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   2319     return MCDisassembler::Fail;
   2320   if (!align)
   2321     Inst.addOperand(MCOperand::createImm(0));
   2322   else
   2323     Inst.addOperand(MCOperand::createImm(4 << align));
   2324 
   2325   return S;
   2326 }
   2327 
   2328 static DecodeStatus DecodeVLDInstruction(MCInst &Inst, unsigned Insn,
   2329                                    uint64_t Address, const void *Decoder) {
   2330   DecodeStatus S = MCDisassembler::Success;
   2331 
   2332   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   2333   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   2334   unsigned wb = fieldFromInstruction(Insn, 16, 4);
   2335   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   2336   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
   2337   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   2338 
   2339   // First output register
   2340   switch (Inst.getOpcode()) {
   2341   case ARM::VLD1q16: case ARM::VLD1q32: case ARM::VLD1q64: case ARM::VLD1q8:
   2342   case ARM::VLD1q16wb_fixed: case ARM::VLD1q16wb_register:
   2343   case ARM::VLD1q32wb_fixed: case ARM::VLD1q32wb_register:
   2344   case ARM::VLD1q64wb_fixed: case ARM::VLD1q64wb_register:
   2345   case ARM::VLD1q8wb_fixed: case ARM::VLD1q8wb_register:
   2346   case ARM::VLD2d16: case ARM::VLD2d32: case ARM::VLD2d8:
   2347   case ARM::VLD2d16wb_fixed: case ARM::VLD2d16wb_register:
   2348   case ARM::VLD2d32wb_fixed: case ARM::VLD2d32wb_register:
   2349   case ARM::VLD2d8wb_fixed: case ARM::VLD2d8wb_register:
   2350     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
   2351       return MCDisassembler::Fail;
   2352     break;
   2353   case ARM::VLD2b16:
   2354   case ARM::VLD2b32:
   2355   case ARM::VLD2b8:
   2356   case ARM::VLD2b16wb_fixed:
   2357   case ARM::VLD2b16wb_register:
   2358   case ARM::VLD2b32wb_fixed:
   2359   case ARM::VLD2b32wb_register:
   2360   case ARM::VLD2b8wb_fixed:
   2361   case ARM::VLD2b8wb_register:
   2362     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
   2363       return MCDisassembler::Fail;
   2364     break;
   2365   default:
   2366     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   2367       return MCDisassembler::Fail;
   2368   }
   2369 
   2370   // Second output register
   2371   switch (Inst.getOpcode()) {
   2372     case ARM::VLD3d8:
   2373     case ARM::VLD3d16:
   2374     case ARM::VLD3d32:
   2375     case ARM::VLD3d8_UPD:
   2376     case ARM::VLD3d16_UPD:
   2377     case ARM::VLD3d32_UPD:
   2378     case ARM::VLD4d8:
   2379     case ARM::VLD4d16:
   2380     case ARM::VLD4d32:
   2381     case ARM::VLD4d8_UPD:
   2382     case ARM::VLD4d16_UPD:
   2383     case ARM::VLD4d32_UPD:
   2384       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
   2385         return MCDisassembler::Fail;
   2386       break;
   2387     case ARM::VLD3q8:
   2388     case ARM::VLD3q16:
   2389     case ARM::VLD3q32:
   2390     case ARM::VLD3q8_UPD:
   2391     case ARM::VLD3q16_UPD:
   2392     case ARM::VLD3q32_UPD:
   2393     case ARM::VLD4q8:
   2394     case ARM::VLD4q16:
   2395     case ARM::VLD4q32:
   2396     case ARM::VLD4q8_UPD:
   2397     case ARM::VLD4q16_UPD:
   2398     case ARM::VLD4q32_UPD:
   2399       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
   2400         return MCDisassembler::Fail;
   2401       break;
   2402     default:
   2403       break;
   2404   }
   2405 
   2406   // Third output register
   2407   switch(Inst.getOpcode()) {
   2408     case ARM::VLD3d8:
   2409     case ARM::VLD3d16:
   2410     case ARM::VLD3d32:
   2411     case ARM::VLD3d8_UPD:
   2412     case ARM::VLD3d16_UPD:
   2413     case ARM::VLD3d32_UPD:
   2414     case ARM::VLD4d8:
   2415     case ARM::VLD4d16:
   2416     case ARM::VLD4d32:
   2417     case ARM::VLD4d8_UPD:
   2418     case ARM::VLD4d16_UPD:
   2419     case ARM::VLD4d32_UPD:
   2420       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
   2421         return MCDisassembler::Fail;
   2422       break;
   2423     case ARM::VLD3q8:
   2424     case ARM::VLD3q16:
   2425     case ARM::VLD3q32:
   2426     case ARM::VLD3q8_UPD:
   2427     case ARM::VLD3q16_UPD:
   2428     case ARM::VLD3q32_UPD:
   2429     case ARM::VLD4q8:
   2430     case ARM::VLD4q16:
   2431     case ARM::VLD4q32:
   2432     case ARM::VLD4q8_UPD:
   2433     case ARM::VLD4q16_UPD:
   2434     case ARM::VLD4q32_UPD:
   2435       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
   2436         return MCDisassembler::Fail;
   2437       break;
   2438     default:
   2439       break;
   2440   }
   2441 
   2442   // Fourth output register
   2443   switch (Inst.getOpcode()) {
   2444     case ARM::VLD4d8:
   2445     case ARM::VLD4d16:
   2446     case ARM::VLD4d32:
   2447     case ARM::VLD4d8_UPD:
   2448     case ARM::VLD4d16_UPD:
   2449     case ARM::VLD4d32_UPD:
   2450       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
   2451         return MCDisassembler::Fail;
   2452       break;
   2453     case ARM::VLD4q8:
   2454     case ARM::VLD4q16:
   2455     case ARM::VLD4q32:
   2456     case ARM::VLD4q8_UPD:
   2457     case ARM::VLD4q16_UPD:
   2458     case ARM::VLD4q32_UPD:
   2459       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
   2460         return MCDisassembler::Fail;
   2461       break;
   2462     default:
   2463       break;
   2464   }
   2465 
   2466   // Writeback operand
   2467   switch (Inst.getOpcode()) {
   2468     case ARM::VLD1d8wb_fixed:
   2469     case ARM::VLD1d16wb_fixed:
   2470     case ARM::VLD1d32wb_fixed:
   2471     case ARM::VLD1d64wb_fixed:
   2472     case ARM::VLD1d8wb_register:
   2473     case ARM::VLD1d16wb_register:
   2474     case ARM::VLD1d32wb_register:
   2475     case ARM::VLD1d64wb_register:
   2476     case ARM::VLD1q8wb_fixed:
   2477     case ARM::VLD1q16wb_fixed:
   2478     case ARM::VLD1q32wb_fixed:
   2479     case ARM::VLD1q64wb_fixed:
   2480     case ARM::VLD1q8wb_register:
   2481     case ARM::VLD1q16wb_register:
   2482     case ARM::VLD1q32wb_register:
   2483     case ARM::VLD1q64wb_register:
   2484     case ARM::VLD1d8Twb_fixed:
   2485     case ARM::VLD1d8Twb_register:
   2486     case ARM::VLD1d16Twb_fixed:
   2487     case ARM::VLD1d16Twb_register:
   2488     case ARM::VLD1d32Twb_fixed:
   2489     case ARM::VLD1d32Twb_register:
   2490     case ARM::VLD1d64Twb_fixed:
   2491     case ARM::VLD1d64Twb_register:
   2492     case ARM::VLD1d8Qwb_fixed:
   2493     case ARM::VLD1d8Qwb_register:
   2494     case ARM::VLD1d16Qwb_fixed:
   2495     case ARM::VLD1d16Qwb_register:
   2496     case ARM::VLD1d32Qwb_fixed:
   2497     case ARM::VLD1d32Qwb_register:
   2498     case ARM::VLD1d64Qwb_fixed:
   2499     case ARM::VLD1d64Qwb_register:
   2500     case ARM::VLD2d8wb_fixed:
   2501     case ARM::VLD2d16wb_fixed:
   2502     case ARM::VLD2d32wb_fixed:
   2503     case ARM::VLD2q8wb_fixed:
   2504     case ARM::VLD2q16wb_fixed:
   2505     case ARM::VLD2q32wb_fixed:
   2506     case ARM::VLD2d8wb_register:
   2507     case ARM::VLD2d16wb_register:
   2508     case ARM::VLD2d32wb_register:
   2509     case ARM::VLD2q8wb_register:
   2510     case ARM::VLD2q16wb_register:
   2511     case ARM::VLD2q32wb_register:
   2512     case ARM::VLD2b8wb_fixed:
   2513     case ARM::VLD2b16wb_fixed:
   2514     case ARM::VLD2b32wb_fixed:
   2515     case ARM::VLD2b8wb_register:
   2516     case ARM::VLD2b16wb_register:
   2517     case ARM::VLD2b32wb_register:
   2518       Inst.addOperand(MCOperand::createImm(0));
   2519       break;
   2520     case ARM::VLD3d8_UPD:
   2521     case ARM::VLD3d16_UPD:
   2522     case ARM::VLD3d32_UPD:
   2523     case ARM::VLD3q8_UPD:
   2524     case ARM::VLD3q16_UPD:
   2525     case ARM::VLD3q32_UPD:
   2526     case ARM::VLD4d8_UPD:
   2527     case ARM::VLD4d16_UPD:
   2528     case ARM::VLD4d32_UPD:
   2529     case ARM::VLD4q8_UPD:
   2530     case ARM::VLD4q16_UPD:
   2531     case ARM::VLD4q32_UPD:
   2532       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
   2533         return MCDisassembler::Fail;
   2534       break;
   2535     default:
   2536       break;
   2537   }
   2538 
   2539   // AddrMode6 Base (register+alignment)
   2540   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
   2541     return MCDisassembler::Fail;
   2542 
   2543   // AddrMode6 Offset (register)
   2544   switch (Inst.getOpcode()) {
   2545   default:
   2546     // The below have been updated to have explicit am6offset split
   2547     // between fixed and register offset. For those instructions not
   2548     // yet updated, we need to add an additional reg0 operand for the
   2549     // fixed variant.
   2550     //
   2551     // The fixed offset encodes as Rm == 0xd, so we check for that.
   2552     if (Rm == 0xd) {
   2553       Inst.addOperand(MCOperand::createReg(0));
   2554       break;
   2555     }
   2556     // Fall through to handle the register offset variant.
   2557     LLVM_FALLTHROUGH;
   2558   case ARM::VLD1d8wb_fixed:
   2559   case ARM::VLD1d16wb_fixed:
   2560   case ARM::VLD1d32wb_fixed:
   2561   case ARM::VLD1d64wb_fixed:
   2562   case ARM::VLD1d8Twb_fixed:
   2563   case ARM::VLD1d16Twb_fixed:
   2564   case ARM::VLD1d32Twb_fixed:
   2565   case ARM::VLD1d64Twb_fixed:
   2566   case ARM::VLD1d8Qwb_fixed:
   2567   case ARM::VLD1d16Qwb_fixed:
   2568   case ARM::VLD1d32Qwb_fixed:
   2569   case ARM::VLD1d64Qwb_fixed:
   2570   case ARM::VLD1d8wb_register:
   2571   case ARM::VLD1d16wb_register:
   2572   case ARM::VLD1d32wb_register:
   2573   case ARM::VLD1d64wb_register:
   2574   case ARM::VLD1q8wb_fixed:
   2575   case ARM::VLD1q16wb_fixed:
   2576   case ARM::VLD1q32wb_fixed:
   2577   case ARM::VLD1q64wb_fixed:
   2578   case ARM::VLD1q8wb_register:
   2579   case ARM::VLD1q16wb_register:
   2580   case ARM::VLD1q32wb_register:
   2581   case ARM::VLD1q64wb_register:
   2582     // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
   2583     // variant encodes Rm == 0xf. Anything else is a register offset post-
   2584     // increment and we need to add the register operand to the instruction.
   2585     if (Rm != 0xD && Rm != 0xF &&
   2586         !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   2587       return MCDisassembler::Fail;
   2588     break;
   2589   case ARM::VLD2d8wb_fixed:
   2590   case ARM::VLD2d16wb_fixed:
   2591   case ARM::VLD2d32wb_fixed:
   2592   case ARM::VLD2b8wb_fixed:
   2593   case ARM::VLD2b16wb_fixed:
   2594   case ARM::VLD2b32wb_fixed:
   2595   case ARM::VLD2q8wb_fixed:
   2596   case ARM::VLD2q16wb_fixed:
   2597   case ARM::VLD2q32wb_fixed:
   2598     break;
   2599   }
   2600 
   2601   return S;
   2602 }
   2603 
   2604 static DecodeStatus DecodeVLDST1Instruction(MCInst &Inst, unsigned Insn,
   2605                                    uint64_t Address, const void *Decoder) {
   2606   unsigned type = fieldFromInstruction(Insn, 8, 4);
   2607   unsigned align = fieldFromInstruction(Insn, 4, 2);
   2608   if (type == 6 && (align & 2)) return MCDisassembler::Fail;
   2609   if (type == 7 && (align & 2)) return MCDisassembler::Fail;
   2610   if (type == 10 && align == 3) return MCDisassembler::Fail;
   2611 
   2612   unsigned load = fieldFromInstruction(Insn, 21, 1);
   2613   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
   2614               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
   2615 }
   2616 
   2617 static DecodeStatus DecodeVLDST2Instruction(MCInst &Inst, unsigned Insn,
   2618                                    uint64_t Address, const void *Decoder) {
   2619   unsigned size = fieldFromInstruction(Insn, 6, 2);
   2620   if (size == 3) return MCDisassembler::Fail;
   2621 
   2622   unsigned type = fieldFromInstruction(Insn, 8, 4);
   2623   unsigned align = fieldFromInstruction(Insn, 4, 2);
   2624   if (type == 8 && align == 3) return MCDisassembler::Fail;
   2625   if (type == 9 && align == 3) return MCDisassembler::Fail;
   2626 
   2627   unsigned load = fieldFromInstruction(Insn, 21, 1);
   2628   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
   2629               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
   2630 }
   2631 
   2632 static DecodeStatus DecodeVLDST3Instruction(MCInst &Inst, unsigned Insn,
   2633                                    uint64_t Address, const void *Decoder) {
   2634   unsigned size = fieldFromInstruction(Insn, 6, 2);
   2635   if (size == 3) return MCDisassembler::Fail;
   2636 
   2637   unsigned align = fieldFromInstruction(Insn, 4, 2);
   2638   if (align & 2) return MCDisassembler::Fail;
   2639 
   2640   unsigned load = fieldFromInstruction(Insn, 21, 1);
   2641   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
   2642               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
   2643 }
   2644 
   2645 static DecodeStatus DecodeVLDST4Instruction(MCInst &Inst, unsigned Insn,
   2646                                    uint64_t Address, const void *Decoder) {
   2647   unsigned size = fieldFromInstruction(Insn, 6, 2);
   2648   if (size == 3) return MCDisassembler::Fail;
   2649 
   2650   unsigned load = fieldFromInstruction(Insn, 21, 1);
   2651   return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
   2652               : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
   2653 }
   2654 
   2655 static DecodeStatus DecodeVSTInstruction(MCInst &Inst, unsigned Insn,
   2656                                  uint64_t Address, const void *Decoder) {
   2657   DecodeStatus S = MCDisassembler::Success;
   2658 
   2659   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   2660   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   2661   unsigned wb = fieldFromInstruction(Insn, 16, 4);
   2662   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   2663   Rn |= fieldFromInstruction(Insn, 4, 2) << 4;
   2664   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   2665 
   2666   // Writeback Operand
   2667   switch (Inst.getOpcode()) {
   2668     case ARM::VST1d8wb_fixed:
   2669     case ARM::VST1d16wb_fixed:
   2670     case ARM::VST1d32wb_fixed:
   2671     case ARM::VST1d64wb_fixed:
   2672     case ARM::VST1d8wb_register:
   2673     case ARM::VST1d16wb_register:
   2674     case ARM::VST1d32wb_register:
   2675     case ARM::VST1d64wb_register:
   2676     case ARM::VST1q8wb_fixed:
   2677     case ARM::VST1q16wb_fixed:
   2678     case ARM::VST1q32wb_fixed:
   2679     case ARM::VST1q64wb_fixed:
   2680     case ARM::VST1q8wb_register:
   2681     case ARM::VST1q16wb_register:
   2682     case ARM::VST1q32wb_register:
   2683     case ARM::VST1q64wb_register:
   2684     case ARM::VST1d8Twb_fixed:
   2685     case ARM::VST1d16Twb_fixed:
   2686     case ARM::VST1d32Twb_fixed:
   2687     case ARM::VST1d64Twb_fixed:
   2688     case ARM::VST1d8Twb_register:
   2689     case ARM::VST1d16Twb_register:
   2690     case ARM::VST1d32Twb_register:
   2691     case ARM::VST1d64Twb_register:
   2692     case ARM::VST1d8Qwb_fixed:
   2693     case ARM::VST1d16Qwb_fixed:
   2694     case ARM::VST1d32Qwb_fixed:
   2695     case ARM::VST1d64Qwb_fixed:
   2696     case ARM::VST1d8Qwb_register:
   2697     case ARM::VST1d16Qwb_register:
   2698     case ARM::VST1d32Qwb_register:
   2699     case ARM::VST1d64Qwb_register:
   2700     case ARM::VST2d8wb_fixed:
   2701     case ARM::VST2d16wb_fixed:
   2702     case ARM::VST2d32wb_fixed:
   2703     case ARM::VST2d8wb_register:
   2704     case ARM::VST2d16wb_register:
   2705     case ARM::VST2d32wb_register:
   2706     case ARM::VST2q8wb_fixed:
   2707     case ARM::VST2q16wb_fixed:
   2708     case ARM::VST2q32wb_fixed:
   2709     case ARM::VST2q8wb_register:
   2710     case ARM::VST2q16wb_register:
   2711     case ARM::VST2q32wb_register:
   2712     case ARM::VST2b8wb_fixed:
   2713     case ARM::VST2b16wb_fixed:
   2714     case ARM::VST2b32wb_fixed:
   2715     case ARM::VST2b8wb_register:
   2716     case ARM::VST2b16wb_register:
   2717     case ARM::VST2b32wb_register:
   2718       if (Rm == 0xF)
   2719         return MCDisassembler::Fail;
   2720       Inst.addOperand(MCOperand::createImm(0));
   2721       break;
   2722     case ARM::VST3d8_UPD:
   2723     case ARM::VST3d16_UPD:
   2724     case ARM::VST3d32_UPD:
   2725     case ARM::VST3q8_UPD:
   2726     case ARM::VST3q16_UPD:
   2727     case ARM::VST3q32_UPD:
   2728     case ARM::VST4d8_UPD:
   2729     case ARM::VST4d16_UPD:
   2730     case ARM::VST4d32_UPD:
   2731     case ARM::VST4q8_UPD:
   2732     case ARM::VST4q16_UPD:
   2733     case ARM::VST4q32_UPD:
   2734       if (!Check(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
   2735         return MCDisassembler::Fail;
   2736       break;
   2737     default:
   2738       break;
   2739   }
   2740 
   2741   // AddrMode6 Base (register+alignment)
   2742   if (!Check(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
   2743     return MCDisassembler::Fail;
   2744 
   2745   // AddrMode6 Offset (register)
   2746   switch (Inst.getOpcode()) {
   2747     default:
   2748       if (Rm == 0xD)
   2749         Inst.addOperand(MCOperand::createReg(0));
   2750       else if (Rm != 0xF) {
   2751         if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   2752           return MCDisassembler::Fail;
   2753       }
   2754       break;
   2755     case ARM::VST1d8wb_fixed:
   2756     case ARM::VST1d16wb_fixed:
   2757     case ARM::VST1d32wb_fixed:
   2758     case ARM::VST1d64wb_fixed:
   2759     case ARM::VST1q8wb_fixed:
   2760     case ARM::VST1q16wb_fixed:
   2761     case ARM::VST1q32wb_fixed:
   2762     case ARM::VST1q64wb_fixed:
   2763     case ARM::VST1d8Twb_fixed:
   2764     case ARM::VST1d16Twb_fixed:
   2765     case ARM::VST1d32Twb_fixed:
   2766     case ARM::VST1d64Twb_fixed:
   2767     case ARM::VST1d8Qwb_fixed:
   2768     case ARM::VST1d16Qwb_fixed:
   2769     case ARM::VST1d32Qwb_fixed:
   2770     case ARM::VST1d64Qwb_fixed:
   2771     case ARM::VST2d8wb_fixed:
   2772     case ARM::VST2d16wb_fixed:
   2773     case ARM::VST2d32wb_fixed:
   2774     case ARM::VST2q8wb_fixed:
   2775     case ARM::VST2q16wb_fixed:
   2776     case ARM::VST2q32wb_fixed:
   2777     case ARM::VST2b8wb_fixed:
   2778     case ARM::VST2b16wb_fixed:
   2779     case ARM::VST2b32wb_fixed:
   2780       break;
   2781   }
   2782 
   2783   // First input register
   2784   switch (Inst.getOpcode()) {
   2785   case ARM::VST1q16:
   2786   case ARM::VST1q32:
   2787   case ARM::VST1q64:
   2788   case ARM::VST1q8:
   2789   case ARM::VST1q16wb_fixed:
   2790   case ARM::VST1q16wb_register:
   2791   case ARM::VST1q32wb_fixed:
   2792   case ARM::VST1q32wb_register:
   2793   case ARM::VST1q64wb_fixed:
   2794   case ARM::VST1q64wb_register:
   2795   case ARM::VST1q8wb_fixed:
   2796   case ARM::VST1q8wb_register:
   2797   case ARM::VST2d16:
   2798   case ARM::VST2d32:
   2799   case ARM::VST2d8:
   2800   case ARM::VST2d16wb_fixed:
   2801   case ARM::VST2d16wb_register:
   2802   case ARM::VST2d32wb_fixed:
   2803   case ARM::VST2d32wb_register:
   2804   case ARM::VST2d8wb_fixed:
   2805   case ARM::VST2d8wb_register:
   2806     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
   2807       return MCDisassembler::Fail;
   2808     break;
   2809   case ARM::VST2b16:
   2810   case ARM::VST2b32:
   2811   case ARM::VST2b8:
   2812   case ARM::VST2b16wb_fixed:
   2813   case ARM::VST2b16wb_register:
   2814   case ARM::VST2b32wb_fixed:
   2815   case ARM::VST2b32wb_register:
   2816   case ARM::VST2b8wb_fixed:
   2817   case ARM::VST2b8wb_register:
   2818     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
   2819       return MCDisassembler::Fail;
   2820     break;
   2821   default:
   2822     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   2823       return MCDisassembler::Fail;
   2824   }
   2825 
   2826   // Second input register
   2827   switch (Inst.getOpcode()) {
   2828     case ARM::VST3d8:
   2829     case ARM::VST3d16:
   2830     case ARM::VST3d32:
   2831     case ARM::VST3d8_UPD:
   2832     case ARM::VST3d16_UPD:
   2833     case ARM::VST3d32_UPD:
   2834     case ARM::VST4d8:
   2835     case ARM::VST4d16:
   2836     case ARM::VST4d32:
   2837     case ARM::VST4d8_UPD:
   2838     case ARM::VST4d16_UPD:
   2839     case ARM::VST4d32_UPD:
   2840       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder)))
   2841         return MCDisassembler::Fail;
   2842       break;
   2843     case ARM::VST3q8:
   2844     case ARM::VST3q16:
   2845     case ARM::VST3q32:
   2846     case ARM::VST3q8_UPD:
   2847     case ARM::VST3q16_UPD:
   2848     case ARM::VST3q32_UPD:
   2849     case ARM::VST4q8:
   2850     case ARM::VST4q16:
   2851     case ARM::VST4q32:
   2852     case ARM::VST4q8_UPD:
   2853     case ARM::VST4q16_UPD:
   2854     case ARM::VST4q32_UPD:
   2855       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
   2856         return MCDisassembler::Fail;
   2857       break;
   2858     default:
   2859       break;
   2860   }
   2861 
   2862   // Third input register
   2863   switch (Inst.getOpcode()) {
   2864     case ARM::VST3d8:
   2865     case ARM::VST3d16:
   2866     case ARM::VST3d32:
   2867     case ARM::VST3d8_UPD:
   2868     case ARM::VST3d16_UPD:
   2869     case ARM::VST3d32_UPD:
   2870     case ARM::VST4d8:
   2871     case ARM::VST4d16:
   2872     case ARM::VST4d32:
   2873     case ARM::VST4d8_UPD:
   2874     case ARM::VST4d16_UPD:
   2875     case ARM::VST4d32_UPD:
   2876       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder)))
   2877         return MCDisassembler::Fail;
   2878       break;
   2879     case ARM::VST3q8:
   2880     case ARM::VST3q16:
   2881     case ARM::VST3q32:
   2882     case ARM::VST3q8_UPD:
   2883     case ARM::VST3q16_UPD:
   2884     case ARM::VST3q32_UPD:
   2885     case ARM::VST4q8:
   2886     case ARM::VST4q16:
   2887     case ARM::VST4q32:
   2888     case ARM::VST4q8_UPD:
   2889     case ARM::VST4q16_UPD:
   2890     case ARM::VST4q32_UPD:
   2891       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder)))
   2892         return MCDisassembler::Fail;
   2893       break;
   2894     default:
   2895       break;
   2896   }
   2897 
   2898   // Fourth input register
   2899   switch (Inst.getOpcode()) {
   2900     case ARM::VST4d8:
   2901     case ARM::VST4d16:
   2902     case ARM::VST4d32:
   2903     case ARM::VST4d8_UPD:
   2904     case ARM::VST4d16_UPD:
   2905     case ARM::VST4d32_UPD:
   2906       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder)))
   2907         return MCDisassembler::Fail;
   2908       break;
   2909     case ARM::VST4q8:
   2910     case ARM::VST4q16:
   2911     case ARM::VST4q32:
   2912     case ARM::VST4q8_UPD:
   2913     case ARM::VST4q16_UPD:
   2914     case ARM::VST4q32_UPD:
   2915       if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder)))
   2916         return MCDisassembler::Fail;
   2917       break;
   2918     default:
   2919       break;
   2920   }
   2921 
   2922   return S;
   2923 }
   2924 
   2925 static DecodeStatus DecodeVLD1DupInstruction(MCInst &Inst, unsigned Insn,
   2926                                     uint64_t Address, const void *Decoder) {
   2927   DecodeStatus S = MCDisassembler::Success;
   2928 
   2929   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   2930   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   2931   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   2932   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   2933   unsigned align = fieldFromInstruction(Insn, 4, 1);
   2934   unsigned size = fieldFromInstruction(Insn, 6, 2);
   2935 
   2936   if (size == 0 && align == 1)
   2937     return MCDisassembler::Fail;
   2938   align *= (1 << size);
   2939 
   2940   switch (Inst.getOpcode()) {
   2941   case ARM::VLD1DUPq16: case ARM::VLD1DUPq32: case ARM::VLD1DUPq8:
   2942   case ARM::VLD1DUPq16wb_fixed: case ARM::VLD1DUPq16wb_register:
   2943   case ARM::VLD1DUPq32wb_fixed: case ARM::VLD1DUPq32wb_register:
   2944   case ARM::VLD1DUPq8wb_fixed: case ARM::VLD1DUPq8wb_register:
   2945     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
   2946       return MCDisassembler::Fail;
   2947     break;
   2948   default:
   2949     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   2950       return MCDisassembler::Fail;
   2951     break;
   2952   }
   2953   if (Rm != 0xF) {
   2954     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   2955       return MCDisassembler::Fail;
   2956   }
   2957 
   2958   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   2959     return MCDisassembler::Fail;
   2960   Inst.addOperand(MCOperand::createImm(align));
   2961 
   2962   // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
   2963   // variant encodes Rm == 0xf. Anything else is a register offset post-
   2964   // increment and we need to add the register operand to the instruction.
   2965   if (Rm != 0xD && Rm != 0xF &&
   2966       !Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   2967     return MCDisassembler::Fail;
   2968 
   2969   return S;
   2970 }
   2971 
   2972 static DecodeStatus DecodeVLD2DupInstruction(MCInst &Inst, unsigned Insn,
   2973                                     uint64_t Address, const void *Decoder) {
   2974   DecodeStatus S = MCDisassembler::Success;
   2975 
   2976   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   2977   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   2978   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   2979   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   2980   unsigned align = fieldFromInstruction(Insn, 4, 1);
   2981   unsigned size = 1 << fieldFromInstruction(Insn, 6, 2);
   2982   align *= 2*size;
   2983 
   2984   switch (Inst.getOpcode()) {
   2985   case ARM::VLD2DUPd16: case ARM::VLD2DUPd32: case ARM::VLD2DUPd8:
   2986   case ARM::VLD2DUPd16wb_fixed: case ARM::VLD2DUPd16wb_register:
   2987   case ARM::VLD2DUPd32wb_fixed: case ARM::VLD2DUPd32wb_register:
   2988   case ARM::VLD2DUPd8wb_fixed: case ARM::VLD2DUPd8wb_register:
   2989     if (!Check(S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
   2990       return MCDisassembler::Fail;
   2991     break;
   2992   case ARM::VLD2DUPd16x2: case ARM::VLD2DUPd32x2: case ARM::VLD2DUPd8x2:
   2993   case ARM::VLD2DUPd16x2wb_fixed: case ARM::VLD2DUPd16x2wb_register:
   2994   case ARM::VLD2DUPd32x2wb_fixed: case ARM::VLD2DUPd32x2wb_register:
   2995   case ARM::VLD2DUPd8x2wb_fixed: case ARM::VLD2DUPd8x2wb_register:
   2996     if (!Check(S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
   2997       return MCDisassembler::Fail;
   2998     break;
   2999   default:
   3000     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   3001       return MCDisassembler::Fail;
   3002     break;
   3003   }
   3004 
   3005   if (Rm != 0xF)
   3006     Inst.addOperand(MCOperand::createImm(0));
   3007 
   3008   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3009     return MCDisassembler::Fail;
   3010   Inst.addOperand(MCOperand::createImm(align));
   3011 
   3012   if (Rm != 0xD && Rm != 0xF) {
   3013     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   3014       return MCDisassembler::Fail;
   3015   }
   3016 
   3017   return S;
   3018 }
   3019 
   3020 static DecodeStatus DecodeVLD3DupInstruction(MCInst &Inst, unsigned Insn,
   3021                                     uint64_t Address, const void *Decoder) {
   3022   DecodeStatus S = MCDisassembler::Success;
   3023 
   3024   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   3025   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   3026   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   3027   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   3028   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
   3029 
   3030   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   3031     return MCDisassembler::Fail;
   3032   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
   3033     return MCDisassembler::Fail;
   3034   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
   3035     return MCDisassembler::Fail;
   3036   if (Rm != 0xF) {
   3037     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3038       return MCDisassembler::Fail;
   3039   }
   3040 
   3041   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3042     return MCDisassembler::Fail;
   3043   Inst.addOperand(MCOperand::createImm(0));
   3044 
   3045   if (Rm == 0xD)
   3046     Inst.addOperand(MCOperand::createReg(0));
   3047   else if (Rm != 0xF) {
   3048     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   3049       return MCDisassembler::Fail;
   3050   }
   3051 
   3052   return S;
   3053 }
   3054 
   3055 static DecodeStatus DecodeVLD4DupInstruction(MCInst &Inst, unsigned Insn,
   3056                                     uint64_t Address, const void *Decoder) {
   3057   DecodeStatus S = MCDisassembler::Success;
   3058 
   3059   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   3060   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   3061   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   3062   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   3063   unsigned size = fieldFromInstruction(Insn, 6, 2);
   3064   unsigned inc = fieldFromInstruction(Insn, 5, 1) + 1;
   3065   unsigned align = fieldFromInstruction(Insn, 4, 1);
   3066 
   3067   if (size == 0x3) {
   3068     if (align == 0)
   3069       return MCDisassembler::Fail;
   3070     align = 16;
   3071   } else {
   3072     if (size == 2) {
   3073       align *= 8;
   3074     } else {
   3075       size = 1 << size;
   3076       align *= 4*size;
   3077     }
   3078   }
   3079 
   3080   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   3081     return MCDisassembler::Fail;
   3082   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)))
   3083     return MCDisassembler::Fail;
   3084   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder)))
   3085     return MCDisassembler::Fail;
   3086   if (!Check(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder)))
   3087     return MCDisassembler::Fail;
   3088   if (Rm != 0xF) {
   3089     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3090       return MCDisassembler::Fail;
   3091   }
   3092 
   3093   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3094     return MCDisassembler::Fail;
   3095   Inst.addOperand(MCOperand::createImm(align));
   3096 
   3097   if (Rm == 0xD)
   3098     Inst.addOperand(MCOperand::createReg(0));
   3099   else if (Rm != 0xF) {
   3100     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   3101       return MCDisassembler::Fail;
   3102   }
   3103 
   3104   return S;
   3105 }
   3106 
   3107 static DecodeStatus
   3108 DecodeNEONModImmInstruction(MCInst &Inst, unsigned Insn,
   3109                             uint64_t Address, const void *Decoder) {
   3110   DecodeStatus S = MCDisassembler::Success;
   3111 
   3112   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   3113   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   3114   unsigned imm = fieldFromInstruction(Insn, 0, 4);
   3115   imm |= fieldFromInstruction(Insn, 16, 3) << 4;
   3116   imm |= fieldFromInstruction(Insn, 24, 1) << 7;
   3117   imm |= fieldFromInstruction(Insn, 8, 4) << 8;
   3118   imm |= fieldFromInstruction(Insn, 5, 1) << 12;
   3119   unsigned Q = fieldFromInstruction(Insn, 6, 1);
   3120 
   3121   if (Q) {
   3122     if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
   3123     return MCDisassembler::Fail;
   3124   } else {
   3125     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   3126     return MCDisassembler::Fail;
   3127   }
   3128 
   3129   Inst.addOperand(MCOperand::createImm(imm));
   3130 
   3131   switch (Inst.getOpcode()) {
   3132     case ARM::VORRiv4i16:
   3133     case ARM::VORRiv2i32:
   3134     case ARM::VBICiv4i16:
   3135     case ARM::VBICiv2i32:
   3136       if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   3137         return MCDisassembler::Fail;
   3138       break;
   3139     case ARM::VORRiv8i16:
   3140     case ARM::VORRiv4i32:
   3141     case ARM::VBICiv8i16:
   3142     case ARM::VBICiv4i32:
   3143       if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
   3144         return MCDisassembler::Fail;
   3145       break;
   3146     default:
   3147       break;
   3148   }
   3149 
   3150   return S;
   3151 }
   3152 
   3153 static DecodeStatus DecodeVSHLMaxInstruction(MCInst &Inst, unsigned Insn,
   3154                                         uint64_t Address, const void *Decoder) {
   3155   DecodeStatus S = MCDisassembler::Success;
   3156 
   3157   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   3158   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   3159   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   3160   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
   3161   unsigned size = fieldFromInstruction(Insn, 18, 2);
   3162 
   3163   if (!Check(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
   3164     return MCDisassembler::Fail;
   3165   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
   3166     return MCDisassembler::Fail;
   3167   Inst.addOperand(MCOperand::createImm(8 << size));
   3168 
   3169   return S;
   3170 }
   3171 
   3172 static DecodeStatus DecodeShiftRight8Imm(MCInst &Inst, unsigned Val,
   3173                                uint64_t Address, const void *Decoder) {
   3174   Inst.addOperand(MCOperand::createImm(8 - Val));
   3175   return MCDisassembler::Success;
   3176 }
   3177 
   3178 static DecodeStatus DecodeShiftRight16Imm(MCInst &Inst, unsigned Val,
   3179                                uint64_t Address, const void *Decoder) {
   3180   Inst.addOperand(MCOperand::createImm(16 - Val));
   3181   return MCDisassembler::Success;
   3182 }
   3183 
   3184 static DecodeStatus DecodeShiftRight32Imm(MCInst &Inst, unsigned Val,
   3185                                uint64_t Address, const void *Decoder) {
   3186   Inst.addOperand(MCOperand::createImm(32 - Val));
   3187   return MCDisassembler::Success;
   3188 }
   3189 
   3190 static DecodeStatus DecodeShiftRight64Imm(MCInst &Inst, unsigned Val,
   3191                                uint64_t Address, const void *Decoder) {
   3192   Inst.addOperand(MCOperand::createImm(64 - Val));
   3193   return MCDisassembler::Success;
   3194 }
   3195 
   3196 static DecodeStatus DecodeTBLInstruction(MCInst &Inst, unsigned Insn,
   3197                                uint64_t Address, const void *Decoder) {
   3198   DecodeStatus S = MCDisassembler::Success;
   3199 
   3200   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   3201   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   3202   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   3203   Rn |= fieldFromInstruction(Insn, 7, 1) << 4;
   3204   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   3205   Rm |= fieldFromInstruction(Insn, 5, 1) << 4;
   3206   unsigned op = fieldFromInstruction(Insn, 6, 1);
   3207 
   3208   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   3209     return MCDisassembler::Fail;
   3210   if (op) {
   3211     if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   3212     return MCDisassembler::Fail; // Writeback
   3213   }
   3214 
   3215   switch (Inst.getOpcode()) {
   3216   case ARM::VTBL2:
   3217   case ARM::VTBX2:
   3218     if (!Check(S, DecodeDPairRegisterClass(Inst, Rn, Address, Decoder)))
   3219       return MCDisassembler::Fail;
   3220     break;
   3221   default:
   3222     if (!Check(S, DecodeDPRRegisterClass(Inst, Rn, Address, Decoder)))
   3223       return MCDisassembler::Fail;
   3224   }
   3225 
   3226   if (!Check(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
   3227     return MCDisassembler::Fail;
   3228 
   3229   return S;
   3230 }
   3231 
   3232 static DecodeStatus DecodeThumbAddSpecialReg(MCInst &Inst, uint16_t Insn,
   3233                                      uint64_t Address, const void *Decoder) {
   3234   DecodeStatus S = MCDisassembler::Success;
   3235 
   3236   unsigned dst = fieldFromInstruction(Insn, 8, 3);
   3237   unsigned imm = fieldFromInstruction(Insn, 0, 8);
   3238 
   3239   if (!Check(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
   3240     return MCDisassembler::Fail;
   3241 
   3242   switch(Inst.getOpcode()) {
   3243     default:
   3244       return MCDisassembler::Fail;
   3245     case ARM::tADR:
   3246       break; // tADR does not explicitly represent the PC as an operand.
   3247     case ARM::tADDrSPi:
   3248       Inst.addOperand(MCOperand::createReg(ARM::SP));
   3249       break;
   3250   }
   3251 
   3252   Inst.addOperand(MCOperand::createImm(imm));
   3253   return S;
   3254 }
   3255 
   3256 static DecodeStatus DecodeThumbBROperand(MCInst &Inst, unsigned Val,
   3257                                  uint64_t Address, const void *Decoder) {
   3258   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<12>(Val<<1) + 4,
   3259                                 true, 2, Inst, Decoder))
   3260     Inst.addOperand(MCOperand::createImm(SignExtend32<12>(Val << 1)));
   3261   return MCDisassembler::Success;
   3262 }
   3263 
   3264 static DecodeStatus DecodeT2BROperand(MCInst &Inst, unsigned Val,
   3265                                  uint64_t Address, const void *Decoder) {
   3266   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<21>(Val) + 4,
   3267                                 true, 4, Inst, Decoder))
   3268     Inst.addOperand(MCOperand::createImm(SignExtend32<21>(Val)));
   3269   return MCDisassembler::Success;
   3270 }
   3271 
   3272 static DecodeStatus DecodeThumbCmpBROperand(MCInst &Inst, unsigned Val,
   3273                                  uint64_t Address, const void *Decoder) {
   3274   if (!tryAddingSymbolicOperand(Address, Address + (Val<<1) + 4,
   3275                                 true, 2, Inst, Decoder))
   3276     Inst.addOperand(MCOperand::createImm(Val << 1));
   3277   return MCDisassembler::Success;
   3278 }
   3279 
   3280 static DecodeStatus DecodeThumbAddrModeRR(MCInst &Inst, unsigned Val,
   3281                                  uint64_t Address, const void *Decoder) {
   3282   DecodeStatus S = MCDisassembler::Success;
   3283 
   3284   unsigned Rn = fieldFromInstruction(Val, 0, 3);
   3285   unsigned Rm = fieldFromInstruction(Val, 3, 3);
   3286 
   3287   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3288     return MCDisassembler::Fail;
   3289   if (!Check(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
   3290     return MCDisassembler::Fail;
   3291 
   3292   return S;
   3293 }
   3294 
   3295 static DecodeStatus DecodeThumbAddrModeIS(MCInst &Inst, unsigned Val,
   3296                                   uint64_t Address, const void *Decoder) {
   3297   DecodeStatus S = MCDisassembler::Success;
   3298 
   3299   unsigned Rn = fieldFromInstruction(Val, 0, 3);
   3300   unsigned imm = fieldFromInstruction(Val, 3, 5);
   3301 
   3302   if (!Check(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3303     return MCDisassembler::Fail;
   3304   Inst.addOperand(MCOperand::createImm(imm));
   3305 
   3306   return S;
   3307 }
   3308 
   3309 static DecodeStatus DecodeThumbAddrModePC(MCInst &Inst, unsigned Val,
   3310                                   uint64_t Address, const void *Decoder) {
   3311   unsigned imm = Val << 2;
   3312 
   3313   Inst.addOperand(MCOperand::createImm(imm));
   3314   tryAddingPcLoadReferenceComment(Address, (Address & ~2u) + imm + 4, Decoder);
   3315 
   3316   return MCDisassembler::Success;
   3317 }
   3318 
   3319 static DecodeStatus DecodeThumbAddrModeSP(MCInst &Inst, unsigned Val,
   3320                                   uint64_t Address, const void *Decoder) {
   3321   Inst.addOperand(MCOperand::createReg(ARM::SP));
   3322   Inst.addOperand(MCOperand::createImm(Val));
   3323 
   3324   return MCDisassembler::Success;
   3325 }
   3326 
   3327 static DecodeStatus DecodeT2AddrModeSOReg(MCInst &Inst, unsigned Val,
   3328                                   uint64_t Address, const void *Decoder) {
   3329   DecodeStatus S = MCDisassembler::Success;
   3330 
   3331   unsigned Rn = fieldFromInstruction(Val, 6, 4);
   3332   unsigned Rm = fieldFromInstruction(Val, 2, 4);
   3333   unsigned imm = fieldFromInstruction(Val, 0, 2);
   3334 
   3335   // Thumb stores cannot use PC as dest register.
   3336   switch (Inst.getOpcode()) {
   3337   case ARM::t2STRHs:
   3338   case ARM::t2STRBs:
   3339   case ARM::t2STRs:
   3340     if (Rn == 15)
   3341       return MCDisassembler::Fail;
   3342     break;
   3343   default:
   3344     break;
   3345   }
   3346 
   3347   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3348     return MCDisassembler::Fail;
   3349   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
   3350     return MCDisassembler::Fail;
   3351   Inst.addOperand(MCOperand::createImm(imm));
   3352 
   3353   return S;
   3354 }
   3355 
   3356 static DecodeStatus DecodeT2LoadShift(MCInst &Inst, unsigned Insn,
   3357                               uint64_t Address, const void *Decoder) {
   3358   DecodeStatus S = MCDisassembler::Success;
   3359 
   3360   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   3361   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   3362 
   3363   const FeatureBitset &featureBits =
   3364     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
   3365 
   3366   bool hasMP = featureBits[ARM::FeatureMP];
   3367   bool hasV7Ops = featureBits[ARM::HasV7Ops];
   3368 
   3369   if (Rn == 15) {
   3370     switch (Inst.getOpcode()) {
   3371     case ARM::t2LDRBs:
   3372       Inst.setOpcode(ARM::t2LDRBpci);
   3373       break;
   3374     case ARM::t2LDRHs:
   3375       Inst.setOpcode(ARM::t2LDRHpci);
   3376       break;
   3377     case ARM::t2LDRSHs:
   3378       Inst.setOpcode(ARM::t2LDRSHpci);
   3379       break;
   3380     case ARM::t2LDRSBs:
   3381       Inst.setOpcode(ARM::t2LDRSBpci);
   3382       break;
   3383     case ARM::t2LDRs:
   3384       Inst.setOpcode(ARM::t2LDRpci);
   3385       break;
   3386     case ARM::t2PLDs:
   3387       Inst.setOpcode(ARM::t2PLDpci);
   3388       break;
   3389     case ARM::t2PLIs:
   3390       Inst.setOpcode(ARM::t2PLIpci);
   3391       break;
   3392     default:
   3393       return MCDisassembler::Fail;
   3394     }
   3395 
   3396     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
   3397   }
   3398 
   3399   if (Rt == 15) {
   3400     switch (Inst.getOpcode()) {
   3401     case ARM::t2LDRSHs:
   3402       return MCDisassembler::Fail;
   3403     case ARM::t2LDRHs:
   3404       Inst.setOpcode(ARM::t2PLDWs);
   3405       break;
   3406     case ARM::t2LDRSBs:
   3407       Inst.setOpcode(ARM::t2PLIs);
   3408       break;
   3409     default:
   3410       break;
   3411     }
   3412   }
   3413 
   3414   switch (Inst.getOpcode()) {
   3415     case ARM::t2PLDs:
   3416       break;
   3417     case ARM::t2PLIs:
   3418       if (!hasV7Ops)
   3419         return MCDisassembler::Fail;
   3420       break;
   3421     case ARM::t2PLDWs:
   3422       if (!hasV7Ops || !hasMP)
   3423         return MCDisassembler::Fail;
   3424       break;
   3425     default:
   3426       if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
   3427         return MCDisassembler::Fail;
   3428   }
   3429 
   3430   unsigned addrmode = fieldFromInstruction(Insn, 4, 2);
   3431   addrmode |= fieldFromInstruction(Insn, 0, 4) << 2;
   3432   addrmode |= fieldFromInstruction(Insn, 16, 4) << 6;
   3433   if (!Check(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
   3434     return MCDisassembler::Fail;
   3435 
   3436   return S;
   3437 }
   3438 
   3439 static DecodeStatus DecodeT2LoadImm8(MCInst &Inst, unsigned Insn,
   3440                                 uint64_t Address, const void* Decoder) {
   3441   DecodeStatus S = MCDisassembler::Success;
   3442 
   3443   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   3444   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   3445   unsigned U = fieldFromInstruction(Insn, 9, 1);
   3446   unsigned imm = fieldFromInstruction(Insn, 0, 8);
   3447   imm |= (U << 8);
   3448   imm |= (Rn << 9);
   3449   unsigned add = fieldFromInstruction(Insn, 9, 1);
   3450 
   3451   const FeatureBitset &featureBits =
   3452     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
   3453 
   3454   bool hasMP = featureBits[ARM::FeatureMP];
   3455   bool hasV7Ops = featureBits[ARM::HasV7Ops];
   3456 
   3457   if (Rn == 15) {
   3458     switch (Inst.getOpcode()) {
   3459     case ARM::t2LDRi8:
   3460       Inst.setOpcode(ARM::t2LDRpci);
   3461       break;
   3462     case ARM::t2LDRBi8:
   3463       Inst.setOpcode(ARM::t2LDRBpci);
   3464       break;
   3465     case ARM::t2LDRSBi8:
   3466       Inst.setOpcode(ARM::t2LDRSBpci);
   3467       break;
   3468     case ARM::t2LDRHi8:
   3469       Inst.setOpcode(ARM::t2LDRHpci);
   3470       break;
   3471     case ARM::t2LDRSHi8:
   3472       Inst.setOpcode(ARM::t2LDRSHpci);
   3473       break;
   3474     case ARM::t2PLDi8:
   3475       Inst.setOpcode(ARM::t2PLDpci);
   3476       break;
   3477     case ARM::t2PLIi8:
   3478       Inst.setOpcode(ARM::t2PLIpci);
   3479       break;
   3480     default:
   3481       return MCDisassembler::Fail;
   3482     }
   3483     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
   3484   }
   3485 
   3486   if (Rt == 15) {
   3487     switch (Inst.getOpcode()) {
   3488     case ARM::t2LDRSHi8:
   3489       return MCDisassembler::Fail;
   3490     case ARM::t2LDRHi8:
   3491       if (!add)
   3492         Inst.setOpcode(ARM::t2PLDWi8);
   3493       break;
   3494     case ARM::t2LDRSBi8:
   3495       Inst.setOpcode(ARM::t2PLIi8);
   3496       break;
   3497     default:
   3498       break;
   3499     }
   3500   }
   3501 
   3502   switch (Inst.getOpcode()) {
   3503   case ARM::t2PLDi8:
   3504     break;
   3505   case ARM::t2PLIi8:
   3506     if (!hasV7Ops)
   3507       return MCDisassembler::Fail;
   3508     break;
   3509   case ARM::t2PLDWi8:
   3510       if (!hasV7Ops || !hasMP)
   3511         return MCDisassembler::Fail;
   3512       break;
   3513   default:
   3514     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
   3515       return MCDisassembler::Fail;
   3516   }
   3517 
   3518   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
   3519     return MCDisassembler::Fail;
   3520   return S;
   3521 }
   3522 
   3523 static DecodeStatus DecodeT2LoadImm12(MCInst &Inst, unsigned Insn,
   3524                                 uint64_t Address, const void* Decoder) {
   3525   DecodeStatus S = MCDisassembler::Success;
   3526 
   3527   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   3528   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   3529   unsigned imm = fieldFromInstruction(Insn, 0, 12);
   3530   imm |= (Rn << 13);
   3531 
   3532   const FeatureBitset &featureBits =
   3533     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
   3534 
   3535   bool hasMP = featureBits[ARM::FeatureMP];
   3536   bool hasV7Ops = featureBits[ARM::HasV7Ops];
   3537 
   3538   if (Rn == 15) {
   3539     switch (Inst.getOpcode()) {
   3540     case ARM::t2LDRi12:
   3541       Inst.setOpcode(ARM::t2LDRpci);
   3542       break;
   3543     case ARM::t2LDRHi12:
   3544       Inst.setOpcode(ARM::t2LDRHpci);
   3545       break;
   3546     case ARM::t2LDRSHi12:
   3547       Inst.setOpcode(ARM::t2LDRSHpci);
   3548       break;
   3549     case ARM::t2LDRBi12:
   3550       Inst.setOpcode(ARM::t2LDRBpci);
   3551       break;
   3552     case ARM::t2LDRSBi12:
   3553       Inst.setOpcode(ARM::t2LDRSBpci);
   3554       break;
   3555     case ARM::t2PLDi12:
   3556       Inst.setOpcode(ARM::t2PLDpci);
   3557       break;
   3558     case ARM::t2PLIi12:
   3559       Inst.setOpcode(ARM::t2PLIpci);
   3560       break;
   3561     default:
   3562       return MCDisassembler::Fail;
   3563     }
   3564     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
   3565   }
   3566 
   3567   if (Rt == 15) {
   3568     switch (Inst.getOpcode()) {
   3569     case ARM::t2LDRSHi12:
   3570       return MCDisassembler::Fail;
   3571     case ARM::t2LDRHi12:
   3572       Inst.setOpcode(ARM::t2PLDWi12);
   3573       break;
   3574     case ARM::t2LDRSBi12:
   3575       Inst.setOpcode(ARM::t2PLIi12);
   3576       break;
   3577     default:
   3578       break;
   3579     }
   3580   }
   3581 
   3582   switch (Inst.getOpcode()) {
   3583   case ARM::t2PLDi12:
   3584     break;
   3585   case ARM::t2PLIi12:
   3586     if (!hasV7Ops)
   3587       return MCDisassembler::Fail;
   3588     break;
   3589   case ARM::t2PLDWi12:
   3590       if (!hasV7Ops || !hasMP)
   3591         return MCDisassembler::Fail;
   3592       break;
   3593   default:
   3594     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
   3595       return MCDisassembler::Fail;
   3596   }
   3597 
   3598   if (!Check(S, DecodeT2AddrModeImm12(Inst, imm, Address, Decoder)))
   3599     return MCDisassembler::Fail;
   3600   return S;
   3601 }
   3602 
   3603 static DecodeStatus DecodeT2LoadT(MCInst &Inst, unsigned Insn,
   3604                                 uint64_t Address, const void* Decoder) {
   3605   DecodeStatus S = MCDisassembler::Success;
   3606 
   3607   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   3608   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   3609   unsigned imm = fieldFromInstruction(Insn, 0, 8);
   3610   imm |= (Rn << 9);
   3611 
   3612   if (Rn == 15) {
   3613     switch (Inst.getOpcode()) {
   3614     case ARM::t2LDRT:
   3615       Inst.setOpcode(ARM::t2LDRpci);
   3616       break;
   3617     case ARM::t2LDRBT:
   3618       Inst.setOpcode(ARM::t2LDRBpci);
   3619       break;
   3620     case ARM::t2LDRHT:
   3621       Inst.setOpcode(ARM::t2LDRHpci);
   3622       break;
   3623     case ARM::t2LDRSBT:
   3624       Inst.setOpcode(ARM::t2LDRSBpci);
   3625       break;
   3626     case ARM::t2LDRSHT:
   3627       Inst.setOpcode(ARM::t2LDRSHpci);
   3628       break;
   3629     default:
   3630       return MCDisassembler::Fail;
   3631     }
   3632     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
   3633   }
   3634 
   3635   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
   3636     return MCDisassembler::Fail;
   3637   if (!Check(S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
   3638     return MCDisassembler::Fail;
   3639   return S;
   3640 }
   3641 
   3642 static DecodeStatus DecodeT2LoadLabel(MCInst &Inst, unsigned Insn,
   3643                                 uint64_t Address, const void* Decoder) {
   3644   DecodeStatus S = MCDisassembler::Success;
   3645 
   3646   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   3647   unsigned U = fieldFromInstruction(Insn, 23, 1);
   3648   int imm = fieldFromInstruction(Insn, 0, 12);
   3649 
   3650   const FeatureBitset &featureBits =
   3651     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
   3652 
   3653   bool hasV7Ops = featureBits[ARM::HasV7Ops];
   3654 
   3655   if (Rt == 15) {
   3656     switch (Inst.getOpcode()) {
   3657       case ARM::t2LDRBpci:
   3658       case ARM::t2LDRHpci:
   3659         Inst.setOpcode(ARM::t2PLDpci);
   3660         break;
   3661       case ARM::t2LDRSBpci:
   3662         Inst.setOpcode(ARM::t2PLIpci);
   3663         break;
   3664       case ARM::t2LDRSHpci:
   3665         return MCDisassembler::Fail;
   3666       default:
   3667         break;
   3668     }
   3669   }
   3670 
   3671   switch(Inst.getOpcode()) {
   3672   case ARM::t2PLDpci:
   3673     break;
   3674   case ARM::t2PLIpci:
   3675     if (!hasV7Ops)
   3676       return MCDisassembler::Fail;
   3677     break;
   3678   default:
   3679     if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
   3680       return MCDisassembler::Fail;
   3681   }
   3682 
   3683   if (!U) {
   3684     // Special case for #-0.
   3685     if (imm == 0)
   3686       imm = INT32_MIN;
   3687     else
   3688       imm = -imm;
   3689   }
   3690   Inst.addOperand(MCOperand::createImm(imm));
   3691 
   3692   return S;
   3693 }
   3694 
   3695 static DecodeStatus DecodeT2Imm8S4(MCInst &Inst, unsigned Val,
   3696                            uint64_t Address, const void *Decoder) {
   3697   if (Val == 0)
   3698     Inst.addOperand(MCOperand::createImm(INT32_MIN));
   3699   else {
   3700     int imm = Val & 0xFF;
   3701 
   3702     if (!(Val & 0x100)) imm *= -1;
   3703     Inst.addOperand(MCOperand::createImm(imm * 4));
   3704   }
   3705 
   3706   return MCDisassembler::Success;
   3707 }
   3708 
   3709 static DecodeStatus DecodeT2AddrModeImm8s4(MCInst &Inst, unsigned Val,
   3710                                    uint64_t Address, const void *Decoder) {
   3711   DecodeStatus S = MCDisassembler::Success;
   3712 
   3713   unsigned Rn = fieldFromInstruction(Val, 9, 4);
   3714   unsigned imm = fieldFromInstruction(Val, 0, 9);
   3715 
   3716   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3717     return MCDisassembler::Fail;
   3718   if (!Check(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
   3719     return MCDisassembler::Fail;
   3720 
   3721   return S;
   3722 }
   3723 
   3724 static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst &Inst,unsigned Val,
   3725                                    uint64_t Address, const void *Decoder) {
   3726   DecodeStatus S = MCDisassembler::Success;
   3727 
   3728   unsigned Rn = fieldFromInstruction(Val, 8, 4);
   3729   unsigned imm = fieldFromInstruction(Val, 0, 8);
   3730 
   3731   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
   3732     return MCDisassembler::Fail;
   3733 
   3734   Inst.addOperand(MCOperand::createImm(imm));
   3735 
   3736   return S;
   3737 }
   3738 
   3739 static DecodeStatus DecodeT2Imm8(MCInst &Inst, unsigned Val,
   3740                          uint64_t Address, const void *Decoder) {
   3741   int imm = Val & 0xFF;
   3742   if (Val == 0)
   3743     imm = INT32_MIN;
   3744   else if (!(Val & 0x100))
   3745     imm *= -1;
   3746   Inst.addOperand(MCOperand::createImm(imm));
   3747 
   3748   return MCDisassembler::Success;
   3749 }
   3750 
   3751 static DecodeStatus DecodeT2AddrModeImm8(MCInst &Inst, unsigned Val,
   3752                                  uint64_t Address, const void *Decoder) {
   3753   DecodeStatus S = MCDisassembler::Success;
   3754 
   3755   unsigned Rn = fieldFromInstruction(Val, 9, 4);
   3756   unsigned imm = fieldFromInstruction(Val, 0, 9);
   3757 
   3758   // Thumb stores cannot use PC as dest register.
   3759   switch (Inst.getOpcode()) {
   3760   case ARM::t2STRT:
   3761   case ARM::t2STRBT:
   3762   case ARM::t2STRHT:
   3763   case ARM::t2STRi8:
   3764   case ARM::t2STRHi8:
   3765   case ARM::t2STRBi8:
   3766     if (Rn == 15)
   3767       return MCDisassembler::Fail;
   3768     break;
   3769   default:
   3770     break;
   3771   }
   3772 
   3773   // Some instructions always use an additive offset.
   3774   switch (Inst.getOpcode()) {
   3775     case ARM::t2LDRT:
   3776     case ARM::t2LDRBT:
   3777     case ARM::t2LDRHT:
   3778     case ARM::t2LDRSBT:
   3779     case ARM::t2LDRSHT:
   3780     case ARM::t2STRT:
   3781     case ARM::t2STRBT:
   3782     case ARM::t2STRHT:
   3783       imm |= 0x100;
   3784       break;
   3785     default:
   3786       break;
   3787   }
   3788 
   3789   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3790     return MCDisassembler::Fail;
   3791   if (!Check(S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
   3792     return MCDisassembler::Fail;
   3793 
   3794   return S;
   3795 }
   3796 
   3797 static DecodeStatus DecodeT2LdStPre(MCInst &Inst, unsigned Insn,
   3798                                     uint64_t Address, const void *Decoder) {
   3799   DecodeStatus S = MCDisassembler::Success;
   3800 
   3801   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   3802   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   3803   unsigned addr = fieldFromInstruction(Insn, 0, 8);
   3804   addr |= fieldFromInstruction(Insn, 9, 1) << 8;
   3805   addr |= Rn << 9;
   3806   unsigned load = fieldFromInstruction(Insn, 20, 1);
   3807 
   3808   if (Rn == 15) {
   3809     switch (Inst.getOpcode()) {
   3810     case ARM::t2LDR_PRE:
   3811     case ARM::t2LDR_POST:
   3812       Inst.setOpcode(ARM::t2LDRpci);
   3813       break;
   3814     case ARM::t2LDRB_PRE:
   3815     case ARM::t2LDRB_POST:
   3816       Inst.setOpcode(ARM::t2LDRBpci);
   3817       break;
   3818     case ARM::t2LDRH_PRE:
   3819     case ARM::t2LDRH_POST:
   3820       Inst.setOpcode(ARM::t2LDRHpci);
   3821       break;
   3822     case ARM::t2LDRSB_PRE:
   3823     case ARM::t2LDRSB_POST:
   3824       if (Rt == 15)
   3825         Inst.setOpcode(ARM::t2PLIpci);
   3826       else
   3827         Inst.setOpcode(ARM::t2LDRSBpci);
   3828       break;
   3829     case ARM::t2LDRSH_PRE:
   3830     case ARM::t2LDRSH_POST:
   3831       Inst.setOpcode(ARM::t2LDRSHpci);
   3832       break;
   3833     default:
   3834       return MCDisassembler::Fail;
   3835     }
   3836     return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
   3837   }
   3838 
   3839   if (!load) {
   3840     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3841       return MCDisassembler::Fail;
   3842   }
   3843 
   3844   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
   3845     return MCDisassembler::Fail;
   3846 
   3847   if (load) {
   3848     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3849       return MCDisassembler::Fail;
   3850   }
   3851 
   3852   if (!Check(S, DecodeT2AddrModeImm8(Inst, addr, Address, Decoder)))
   3853     return MCDisassembler::Fail;
   3854 
   3855   return S;
   3856 }
   3857 
   3858 static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
   3859                                   uint64_t Address, const void *Decoder) {
   3860   DecodeStatus S = MCDisassembler::Success;
   3861 
   3862   unsigned Rn = fieldFromInstruction(Val, 13, 4);
   3863   unsigned imm = fieldFromInstruction(Val, 0, 12);
   3864 
   3865   // Thumb stores cannot use PC as dest register.
   3866   switch (Inst.getOpcode()) {
   3867   case ARM::t2STRi12:
   3868   case ARM::t2STRBi12:
   3869   case ARM::t2STRHi12:
   3870     if (Rn == 15)
   3871       return MCDisassembler::Fail;
   3872     break;
   3873   default:
   3874     break;
   3875   }
   3876 
   3877   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3878     return MCDisassembler::Fail;
   3879   Inst.addOperand(MCOperand::createImm(imm));
   3880 
   3881   return S;
   3882 }
   3883 
   3884 static DecodeStatus DecodeThumbAddSPImm(MCInst &Inst, uint16_t Insn,
   3885                                 uint64_t Address, const void *Decoder) {
   3886   unsigned imm = fieldFromInstruction(Insn, 0, 7);
   3887 
   3888   Inst.addOperand(MCOperand::createReg(ARM::SP));
   3889   Inst.addOperand(MCOperand::createReg(ARM::SP));
   3890   Inst.addOperand(MCOperand::createImm(imm));
   3891 
   3892   return MCDisassembler::Success;
   3893 }
   3894 
   3895 static DecodeStatus DecodeThumbAddSPReg(MCInst &Inst, uint16_t Insn,
   3896                                 uint64_t Address, const void *Decoder) {
   3897   DecodeStatus S = MCDisassembler::Success;
   3898 
   3899   if (Inst.getOpcode() == ARM::tADDrSP) {
   3900     unsigned Rdm = fieldFromInstruction(Insn, 0, 3);
   3901     Rdm |= fieldFromInstruction(Insn, 7, 1) << 3;
   3902 
   3903     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
   3904     return MCDisassembler::Fail;
   3905     Inst.addOperand(MCOperand::createReg(ARM::SP));
   3906     if (!Check(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
   3907     return MCDisassembler::Fail;
   3908   } else if (Inst.getOpcode() == ARM::tADDspr) {
   3909     unsigned Rm = fieldFromInstruction(Insn, 3, 4);
   3910 
   3911     Inst.addOperand(MCOperand::createReg(ARM::SP));
   3912     Inst.addOperand(MCOperand::createReg(ARM::SP));
   3913     if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   3914     return MCDisassembler::Fail;
   3915   }
   3916 
   3917   return S;
   3918 }
   3919 
   3920 static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
   3921                            uint64_t Address, const void *Decoder) {
   3922   unsigned imod = fieldFromInstruction(Insn, 4, 1) | 0x2;
   3923   unsigned flags = fieldFromInstruction(Insn, 0, 3);
   3924 
   3925   Inst.addOperand(MCOperand::createImm(imod));
   3926   Inst.addOperand(MCOperand::createImm(flags));
   3927 
   3928   return MCDisassembler::Success;
   3929 }
   3930 
   3931 static DecodeStatus DecodePostIdxReg(MCInst &Inst, unsigned Insn,
   3932                              uint64_t Address, const void *Decoder) {
   3933   DecodeStatus S = MCDisassembler::Success;
   3934   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   3935   unsigned add = fieldFromInstruction(Insn, 4, 1);
   3936 
   3937   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
   3938     return MCDisassembler::Fail;
   3939   Inst.addOperand(MCOperand::createImm(add));
   3940 
   3941   return S;
   3942 }
   3943 
   3944 static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Val,
   3945                                  uint64_t Address, const void *Decoder) {
   3946   // Val is passed in as S:J1:J2:imm10H:imm10L:'0'
   3947   // Note only one trailing zero not two.  Also the J1 and J2 values are from
   3948   // the encoded instruction.  So here change to I1 and I2 values via:
   3949   // I1 = NOT(J1 EOR S);
   3950   // I2 = NOT(J2 EOR S);
   3951   // and build the imm32 with two trailing zeros as documented:
   3952   // imm32 = SignExtend(S:I1:I2:imm10H:imm10L:'00', 32);
   3953   unsigned S = (Val >> 23) & 1;
   3954   unsigned J1 = (Val >> 22) & 1;
   3955   unsigned J2 = (Val >> 21) & 1;
   3956   unsigned I1 = !(J1 ^ S);
   3957   unsigned I2 = !(J2 ^ S);
   3958   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
   3959   int imm32 = SignExtend32<25>(tmp << 1);
   3960 
   3961   if (!tryAddingSymbolicOperand(Address,
   3962                                 (Address & ~2u) + imm32 + 4,
   3963                                 true, 4, Inst, Decoder))
   3964     Inst.addOperand(MCOperand::createImm(imm32));
   3965   return MCDisassembler::Success;
   3966 }
   3967 
   3968 static DecodeStatus DecodeCoprocessor(MCInst &Inst, unsigned Val,
   3969                               uint64_t Address, const void *Decoder) {
   3970   if (Val == 0xA || Val == 0xB)
   3971     return MCDisassembler::Fail;
   3972 
   3973   const FeatureBitset &featureBits =
   3974     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
   3975 
   3976   if (featureBits[ARM::HasV8Ops] && !(Val == 14 || Val == 15))
   3977     return MCDisassembler::Fail;
   3978 
   3979   Inst.addOperand(MCOperand::createImm(Val));
   3980   return MCDisassembler::Success;
   3981 }
   3982 
   3983 static DecodeStatus
   3984 DecodeThumbTableBranch(MCInst &Inst, unsigned Insn,
   3985                        uint64_t Address, const void *Decoder) {
   3986   DecodeStatus S = MCDisassembler::Success;
   3987 
   3988   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   3989   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   3990 
   3991   if (Rn == ARM::SP) S = MCDisassembler::SoftFail;
   3992   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   3993     return MCDisassembler::Fail;
   3994   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
   3995     return MCDisassembler::Fail;
   3996   return S;
   3997 }
   3998 
   3999 static DecodeStatus
   4000 DecodeThumb2BCCInstruction(MCInst &Inst, unsigned Insn,
   4001                            uint64_t Address, const void *Decoder) {
   4002   DecodeStatus S = MCDisassembler::Success;
   4003 
   4004   unsigned pred = fieldFromInstruction(Insn, 22, 4);
   4005   if (pred == 0xE || pred == 0xF) {
   4006     unsigned opc = fieldFromInstruction(Insn, 4, 28);
   4007     switch (opc) {
   4008       default:
   4009         return MCDisassembler::Fail;
   4010       case 0xf3bf8f4:
   4011         Inst.setOpcode(ARM::t2DSB);
   4012         break;
   4013       case 0xf3bf8f5:
   4014         Inst.setOpcode(ARM::t2DMB);
   4015         break;
   4016       case 0xf3bf8f6:
   4017         Inst.setOpcode(ARM::t2ISB);
   4018         break;
   4019     }
   4020 
   4021     unsigned imm = fieldFromInstruction(Insn, 0, 4);
   4022     return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
   4023   }
   4024 
   4025   unsigned brtarget = fieldFromInstruction(Insn, 0, 11) << 1;
   4026   brtarget |= fieldFromInstruction(Insn, 11, 1) << 19;
   4027   brtarget |= fieldFromInstruction(Insn, 13, 1) << 18;
   4028   brtarget |= fieldFromInstruction(Insn, 16, 6) << 12;
   4029   brtarget |= fieldFromInstruction(Insn, 26, 1) << 20;
   4030 
   4031   if (!Check(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
   4032     return MCDisassembler::Fail;
   4033   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   4034     return MCDisassembler::Fail;
   4035 
   4036   return S;
   4037 }
   4038 
   4039 // Decode a shifted immediate operand.  These basically consist
   4040 // of an 8-bit value, and a 4-bit directive that specifies either
   4041 // a splat operation or a rotation.
   4042 static DecodeStatus DecodeT2SOImm(MCInst &Inst, unsigned Val,
   4043                           uint64_t Address, const void *Decoder) {
   4044   unsigned ctrl = fieldFromInstruction(Val, 10, 2);
   4045   if (ctrl == 0) {
   4046     unsigned byte = fieldFromInstruction(Val, 8, 2);
   4047     unsigned imm = fieldFromInstruction(Val, 0, 8);
   4048     switch (byte) {
   4049       case 0:
   4050         Inst.addOperand(MCOperand::createImm(imm));
   4051         break;
   4052       case 1:
   4053         Inst.addOperand(MCOperand::createImm((imm << 16) | imm));
   4054         break;
   4055       case 2:
   4056         Inst.addOperand(MCOperand::createImm((imm << 24) | (imm << 8)));
   4057         break;
   4058       case 3:
   4059         Inst.addOperand(MCOperand::createImm((imm << 24) | (imm << 16) |
   4060                                              (imm << 8)  |  imm));
   4061         break;
   4062     }
   4063   } else {
   4064     unsigned unrot = fieldFromInstruction(Val, 0, 7) | 0x80;
   4065     unsigned rot = fieldFromInstruction(Val, 7, 5);
   4066     unsigned imm = (unrot >> rot) | (unrot << ((32-rot)&31));
   4067     Inst.addOperand(MCOperand::createImm(imm));
   4068   }
   4069 
   4070   return MCDisassembler::Success;
   4071 }
   4072 
   4073 static DecodeStatus
   4074 DecodeThumbBCCTargetOperand(MCInst &Inst, unsigned Val,
   4075                             uint64_t Address, const void *Decoder) {
   4076   if (!tryAddingSymbolicOperand(Address, Address + SignExtend32<9>(Val<<1) + 4,
   4077                                 true, 2, Inst, Decoder))
   4078     Inst.addOperand(MCOperand::createImm(SignExtend32<9>(Val << 1)));
   4079   return MCDisassembler::Success;
   4080 }
   4081 
   4082 static DecodeStatus DecodeThumbBLTargetOperand(MCInst &Inst, unsigned Val,
   4083                                                uint64_t Address,
   4084                                                const void *Decoder) {
   4085   // Val is passed in as S:J1:J2:imm10:imm11
   4086   // Note no trailing zero after imm11.  Also the J1 and J2 values are from
   4087   // the encoded instruction.  So here change to I1 and I2 values via:
   4088   // I1 = NOT(J1 EOR S);
   4089   // I2 = NOT(J2 EOR S);
   4090   // and build the imm32 with one trailing zero as documented:
   4091   // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
   4092   unsigned S = (Val >> 23) & 1;
   4093   unsigned J1 = (Val >> 22) & 1;
   4094   unsigned J2 = (Val >> 21) & 1;
   4095   unsigned I1 = !(J1 ^ S);
   4096   unsigned I2 = !(J2 ^ S);
   4097   unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
   4098   int imm32 = SignExtend32<25>(tmp << 1);
   4099 
   4100   if (!tryAddingSymbolicOperand(Address, Address + imm32 + 4,
   4101                                 true, 4, Inst, Decoder))
   4102     Inst.addOperand(MCOperand::createImm(imm32));
   4103   return MCDisassembler::Success;
   4104 }
   4105 
   4106 static DecodeStatus DecodeMemBarrierOption(MCInst &Inst, unsigned Val,
   4107                                    uint64_t Address, const void *Decoder) {
   4108   if (Val & ~0xf)
   4109     return MCDisassembler::Fail;
   4110 
   4111   Inst.addOperand(MCOperand::createImm(Val));
   4112   return MCDisassembler::Success;
   4113 }
   4114 
   4115 static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Val,
   4116                                         uint64_t Address, const void *Decoder) {
   4117   if (Val & ~0xf)
   4118     return MCDisassembler::Fail;
   4119 
   4120   Inst.addOperand(MCOperand::createImm(Val));
   4121   return MCDisassembler::Success;
   4122 }
   4123 
   4124 static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val,
   4125                           uint64_t Address, const void *Decoder) {
   4126   DecodeStatus S = MCDisassembler::Success;
   4127   const FeatureBitset &FeatureBits =
   4128     ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
   4129 
   4130   if (FeatureBits[ARM::FeatureMClass]) {
   4131     unsigned ValLow = Val & 0xff;
   4132 
   4133     // Validate the SYSm value first.
   4134     switch (ValLow) {
   4135     case  0: // apsr
   4136     case  1: // iapsr
   4137     case  2: // eapsr
   4138     case  3: // xpsr
   4139     case  5: // ipsr
   4140     case  6: // epsr
   4141     case  7: // iepsr
   4142     case  8: // msp
   4143     case  9: // psp
   4144     case 16: // primask
   4145     case 20: // control
   4146       break;
   4147     case 17: // basepri
   4148     case 18: // basepri_max
   4149     case 19: // faultmask
   4150       if (!(FeatureBits[ARM::HasV7Ops]))
   4151         // Values basepri, basepri_max and faultmask are only valid for v7m.
   4152         return MCDisassembler::Fail;
   4153       break;
   4154     case 0x8a: // msplim_ns
   4155     case 0x8b: // psplim_ns
   4156     case 0x91: // basepri_ns
   4157     case 0x93: // faultmask_ns
   4158       if (!(FeatureBits[ARM::HasV8MMainlineOps]))
   4159         return MCDisassembler::Fail;
   4160       LLVM_FALLTHROUGH;
   4161     case 10:   // msplim
   4162     case 11:   // psplim
   4163     case 0x88: // msp_ns
   4164     case 0x89: // psp_ns
   4165     case 0x90: // primask_ns
   4166     case 0x94: // control_ns
   4167     case 0x98: // sp_ns
   4168       if (!(FeatureBits[ARM::Feature8MSecExt]))
   4169         return MCDisassembler::Fail;
   4170       break;
   4171     default:
   4172       // Architecturally defined as unpredictable
   4173       S = MCDisassembler::SoftFail;
   4174       break;
   4175     }
   4176 
   4177     if (Inst.getOpcode() == ARM::t2MSR_M) {
   4178       unsigned Mask = fieldFromInstruction(Val, 10, 2);
   4179       if (!(FeatureBits[ARM::HasV7Ops])) {
   4180         // The ARMv6-M MSR bits {11-10} can be only 0b10, other values are
   4181         // unpredictable.
   4182         if (Mask != 2)
   4183           S = MCDisassembler::SoftFail;
   4184       }
   4185       else {
   4186         // The ARMv7-M architecture stores an additional 2-bit mask value in
   4187         // MSR bits {11-10}. The mask is used only with apsr, iapsr, eapsr and
   4188         // xpsr, it has to be 0b10 in other cases. Bit mask{1} indicates if
   4189         // the NZCVQ bits should be moved by the instruction. Bit mask{0}
   4190         // indicates the move for the GE{3:0} bits, the mask{0} bit can be set
   4191         // only if the processor includes the DSP extension.
   4192         if (Mask == 0 || (Mask != 2 && ValLow > 3) ||
   4193             (!(FeatureBits[ARM::FeatureDSP]) && (Mask & 1)))
   4194           S = MCDisassembler::SoftFail;
   4195       }
   4196     }
   4197   } else {
   4198     // A/R class
   4199     if (Val == 0)
   4200       return MCDisassembler::Fail;
   4201   }
   4202   Inst.addOperand(MCOperand::createImm(Val));
   4203   return S;
   4204 }
   4205 
   4206 static DecodeStatus DecodeBankedReg(MCInst &Inst, unsigned Val,
   4207                                     uint64_t Address, const void *Decoder) {
   4208   unsigned R = fieldFromInstruction(Val, 5, 1);
   4209   unsigned SysM = fieldFromInstruction(Val, 0, 5);
   4210 
   4211   // The table of encodings for these banked registers comes from B9.2.3 of the
   4212   // ARM ARM. There are patterns, but nothing regular enough to make this logic
   4213   // neater. So by fiat, these values are UNPREDICTABLE:
   4214   if (!ARMBankedReg::lookupBankedRegByEncoding((R << 5) | SysM))
   4215     return MCDisassembler::Fail;
   4216 
   4217   Inst.addOperand(MCOperand::createImm(Val));
   4218   return MCDisassembler::Success;
   4219 }
   4220 
   4221 static DecodeStatus DecodeDoubleRegLoad(MCInst &Inst, unsigned Insn,
   4222                                         uint64_t Address, const void *Decoder) {
   4223   DecodeStatus S = MCDisassembler::Success;
   4224 
   4225   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   4226   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4227   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   4228 
   4229   if (Rn == 0xF)
   4230     S = MCDisassembler::SoftFail;
   4231 
   4232   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
   4233     return MCDisassembler::Fail;
   4234   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4235     return MCDisassembler::Fail;
   4236   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   4237     return MCDisassembler::Fail;
   4238 
   4239   return S;
   4240 }
   4241 
   4242 static DecodeStatus DecodeDoubleRegStore(MCInst &Inst, unsigned Insn,
   4243                                          uint64_t Address,
   4244                                          const void *Decoder) {
   4245   DecodeStatus S = MCDisassembler::Success;
   4246 
   4247   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   4248   unsigned Rt = fieldFromInstruction(Insn, 0, 4);
   4249   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4250   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   4251 
   4252   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
   4253     return MCDisassembler::Fail;
   4254 
   4255   if (Rn == 0xF || Rd == Rn || Rd == Rt || Rd == Rt+1)
   4256     S = MCDisassembler::SoftFail;
   4257 
   4258   if (!Check(S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
   4259     return MCDisassembler::Fail;
   4260   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4261     return MCDisassembler::Fail;
   4262   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   4263     return MCDisassembler::Fail;
   4264 
   4265   return S;
   4266 }
   4267 
   4268 static DecodeStatus DecodeLDRPreImm(MCInst &Inst, unsigned Insn,
   4269                             uint64_t Address, const void *Decoder) {
   4270   DecodeStatus S = MCDisassembler::Success;
   4271 
   4272   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4273   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   4274   unsigned imm = fieldFromInstruction(Insn, 0, 12);
   4275   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
   4276   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
   4277   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   4278 
   4279   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
   4280 
   4281   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
   4282     return MCDisassembler::Fail;
   4283   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4284     return MCDisassembler::Fail;
   4285   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
   4286     return MCDisassembler::Fail;
   4287   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   4288     return MCDisassembler::Fail;
   4289 
   4290   return S;
   4291 }
   4292 
   4293 static DecodeStatus DecodeLDRPreReg(MCInst &Inst, unsigned Insn,
   4294                             uint64_t Address, const void *Decoder) {
   4295   DecodeStatus S = MCDisassembler::Success;
   4296 
   4297   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4298   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   4299   unsigned imm = fieldFromInstruction(Insn, 0, 12);
   4300   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
   4301   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
   4302   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   4303   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   4304 
   4305   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
   4306   if (Rm == 0xF) S = MCDisassembler::SoftFail;
   4307 
   4308   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
   4309     return MCDisassembler::Fail;
   4310   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4311     return MCDisassembler::Fail;
   4312   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
   4313     return MCDisassembler::Fail;
   4314   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   4315     return MCDisassembler::Fail;
   4316 
   4317   return S;
   4318 }
   4319 
   4320 static DecodeStatus DecodeSTRPreImm(MCInst &Inst, unsigned Insn,
   4321                             uint64_t Address, const void *Decoder) {
   4322   DecodeStatus S = MCDisassembler::Success;
   4323 
   4324   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4325   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   4326   unsigned imm = fieldFromInstruction(Insn, 0, 12);
   4327   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
   4328   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
   4329   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   4330 
   4331   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
   4332 
   4333   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4334     return MCDisassembler::Fail;
   4335   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
   4336     return MCDisassembler::Fail;
   4337   if (!Check(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
   4338     return MCDisassembler::Fail;
   4339   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   4340     return MCDisassembler::Fail;
   4341 
   4342   return S;
   4343 }
   4344 
   4345 static DecodeStatus DecodeSTRPreReg(MCInst &Inst, unsigned Insn,
   4346                             uint64_t Address, const void *Decoder) {
   4347   DecodeStatus S = MCDisassembler::Success;
   4348 
   4349   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4350   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   4351   unsigned imm = fieldFromInstruction(Insn, 0, 12);
   4352   imm |= fieldFromInstruction(Insn, 16, 4) << 13;
   4353   imm |= fieldFromInstruction(Insn, 23, 1) << 12;
   4354   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   4355 
   4356   if (Rn == 0xF || Rn == Rt) S = MCDisassembler::SoftFail;
   4357 
   4358   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4359     return MCDisassembler::Fail;
   4360   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
   4361     return MCDisassembler::Fail;
   4362   if (!Check(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
   4363     return MCDisassembler::Fail;
   4364   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   4365     return MCDisassembler::Fail;
   4366 
   4367   return S;
   4368 }
   4369 
   4370 static DecodeStatus DecodeVLD1LN(MCInst &Inst, unsigned Insn,
   4371                          uint64_t Address, const void *Decoder) {
   4372   DecodeStatus S = MCDisassembler::Success;
   4373 
   4374   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4375   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   4376   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   4377   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   4378   unsigned size = fieldFromInstruction(Insn, 10, 2);
   4379 
   4380   unsigned align = 0;
   4381   unsigned index = 0;
   4382   switch (size) {
   4383     default:
   4384       return MCDisassembler::Fail;
   4385     case 0:
   4386       if (fieldFromInstruction(Insn, 4, 1))
   4387         return MCDisassembler::Fail; // UNDEFINED
   4388       index = fieldFromInstruction(Insn, 5, 3);
   4389       break;
   4390     case 1:
   4391       if (fieldFromInstruction(Insn, 5, 1))
   4392         return MCDisassembler::Fail; // UNDEFINED
   4393       index = fieldFromInstruction(Insn, 6, 2);
   4394       if (fieldFromInstruction(Insn, 4, 1))
   4395         align = 2;
   4396       break;
   4397     case 2:
   4398       if (fieldFromInstruction(Insn, 6, 1))
   4399         return MCDisassembler::Fail; // UNDEFINED
   4400       index = fieldFromInstruction(Insn, 7, 1);
   4401 
   4402       switch (fieldFromInstruction(Insn, 4, 2)) {
   4403         case 0 :
   4404           align = 0; break;
   4405         case 3:
   4406           align = 4; break;
   4407         default:
   4408           return MCDisassembler::Fail;
   4409       }
   4410       break;
   4411   }
   4412 
   4413   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4414     return MCDisassembler::Fail;
   4415   if (Rm != 0xF) { // Writeback
   4416     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4417       return MCDisassembler::Fail;
   4418   }
   4419   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4420     return MCDisassembler::Fail;
   4421   Inst.addOperand(MCOperand::createImm(align));
   4422   if (Rm != 0xF) {
   4423     if (Rm != 0xD) {
   4424       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   4425         return MCDisassembler::Fail;
   4426     } else
   4427       Inst.addOperand(MCOperand::createReg(0));
   4428   }
   4429 
   4430   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4431     return MCDisassembler::Fail;
   4432   Inst.addOperand(MCOperand::createImm(index));
   4433 
   4434   return S;
   4435 }
   4436 
   4437 static DecodeStatus DecodeVST1LN(MCInst &Inst, unsigned Insn,
   4438                          uint64_t Address, const void *Decoder) {
   4439   DecodeStatus S = MCDisassembler::Success;
   4440 
   4441   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4442   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   4443   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   4444   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   4445   unsigned size = fieldFromInstruction(Insn, 10, 2);
   4446 
   4447   unsigned align = 0;
   4448   unsigned index = 0;
   4449   switch (size) {
   4450     default:
   4451       return MCDisassembler::Fail;
   4452     case 0:
   4453       if (fieldFromInstruction(Insn, 4, 1))
   4454         return MCDisassembler::Fail; // UNDEFINED
   4455       index = fieldFromInstruction(Insn, 5, 3);
   4456       break;
   4457     case 1:
   4458       if (fieldFromInstruction(Insn, 5, 1))
   4459         return MCDisassembler::Fail; // UNDEFINED
   4460       index = fieldFromInstruction(Insn, 6, 2);
   4461       if (fieldFromInstruction(Insn, 4, 1))
   4462         align = 2;
   4463       break;
   4464     case 2:
   4465       if (fieldFromInstruction(Insn, 6, 1))
   4466         return MCDisassembler::Fail; // UNDEFINED
   4467       index = fieldFromInstruction(Insn, 7, 1);
   4468 
   4469       switch (fieldFromInstruction(Insn, 4, 2)) {
   4470         case 0:
   4471           align = 0; break;
   4472         case 3:
   4473           align = 4; break;
   4474         default:
   4475           return MCDisassembler::Fail;
   4476       }
   4477       break;
   4478   }
   4479 
   4480   if (Rm != 0xF) { // Writeback
   4481     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4482     return MCDisassembler::Fail;
   4483   }
   4484   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4485     return MCDisassembler::Fail;
   4486   Inst.addOperand(MCOperand::createImm(align));
   4487   if (Rm != 0xF) {
   4488     if (Rm != 0xD) {
   4489       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   4490     return MCDisassembler::Fail;
   4491     } else
   4492       Inst.addOperand(MCOperand::createReg(0));
   4493   }
   4494 
   4495   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4496     return MCDisassembler::Fail;
   4497   Inst.addOperand(MCOperand::createImm(index));
   4498 
   4499   return S;
   4500 }
   4501 
   4502 static DecodeStatus DecodeVLD2LN(MCInst &Inst, unsigned Insn,
   4503                          uint64_t Address, const void *Decoder) {
   4504   DecodeStatus S = MCDisassembler::Success;
   4505 
   4506   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4507   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   4508   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   4509   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   4510   unsigned size = fieldFromInstruction(Insn, 10, 2);
   4511 
   4512   unsigned align = 0;
   4513   unsigned index = 0;
   4514   unsigned inc = 1;
   4515   switch (size) {
   4516     default:
   4517       return MCDisassembler::Fail;
   4518     case 0:
   4519       index = fieldFromInstruction(Insn, 5, 3);
   4520       if (fieldFromInstruction(Insn, 4, 1))
   4521         align = 2;
   4522       break;
   4523     case 1:
   4524       index = fieldFromInstruction(Insn, 6, 2);
   4525       if (fieldFromInstruction(Insn, 4, 1))
   4526         align = 4;
   4527       if (fieldFromInstruction(Insn, 5, 1))
   4528         inc = 2;
   4529       break;
   4530     case 2:
   4531       if (fieldFromInstruction(Insn, 5, 1))
   4532         return MCDisassembler::Fail; // UNDEFINED
   4533       index = fieldFromInstruction(Insn, 7, 1);
   4534       if (fieldFromInstruction(Insn, 4, 1) != 0)
   4535         align = 8;
   4536       if (fieldFromInstruction(Insn, 6, 1))
   4537         inc = 2;
   4538       break;
   4539   }
   4540 
   4541   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4542     return MCDisassembler::Fail;
   4543   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
   4544     return MCDisassembler::Fail;
   4545   if (Rm != 0xF) { // Writeback
   4546     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4547       return MCDisassembler::Fail;
   4548   }
   4549   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4550     return MCDisassembler::Fail;
   4551   Inst.addOperand(MCOperand::createImm(align));
   4552   if (Rm != 0xF) {
   4553     if (Rm != 0xD) {
   4554       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   4555         return MCDisassembler::Fail;
   4556     } else
   4557       Inst.addOperand(MCOperand::createReg(0));
   4558   }
   4559 
   4560   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4561     return MCDisassembler::Fail;
   4562   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
   4563     return MCDisassembler::Fail;
   4564   Inst.addOperand(MCOperand::createImm(index));
   4565 
   4566   return S;
   4567 }
   4568 
   4569 static DecodeStatus DecodeVST2LN(MCInst &Inst, unsigned Insn,
   4570                          uint64_t Address, const void *Decoder) {
   4571   DecodeStatus S = MCDisassembler::Success;
   4572 
   4573   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4574   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   4575   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   4576   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   4577   unsigned size = fieldFromInstruction(Insn, 10, 2);
   4578 
   4579   unsigned align = 0;
   4580   unsigned index = 0;
   4581   unsigned inc = 1;
   4582   switch (size) {
   4583     default:
   4584       return MCDisassembler::Fail;
   4585     case 0:
   4586       index = fieldFromInstruction(Insn, 5, 3);
   4587       if (fieldFromInstruction(Insn, 4, 1))
   4588         align = 2;
   4589       break;
   4590     case 1:
   4591       index = fieldFromInstruction(Insn, 6, 2);
   4592       if (fieldFromInstruction(Insn, 4, 1))
   4593         align = 4;
   4594       if (fieldFromInstruction(Insn, 5, 1))
   4595         inc = 2;
   4596       break;
   4597     case 2:
   4598       if (fieldFromInstruction(Insn, 5, 1))
   4599         return MCDisassembler::Fail; // UNDEFINED
   4600       index = fieldFromInstruction(Insn, 7, 1);
   4601       if (fieldFromInstruction(Insn, 4, 1) != 0)
   4602         align = 8;
   4603       if (fieldFromInstruction(Insn, 6, 1))
   4604         inc = 2;
   4605       break;
   4606   }
   4607 
   4608   if (Rm != 0xF) { // Writeback
   4609     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4610       return MCDisassembler::Fail;
   4611   }
   4612   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4613     return MCDisassembler::Fail;
   4614   Inst.addOperand(MCOperand::createImm(align));
   4615   if (Rm != 0xF) {
   4616     if (Rm != 0xD) {
   4617       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   4618         return MCDisassembler::Fail;
   4619     } else
   4620       Inst.addOperand(MCOperand::createReg(0));
   4621   }
   4622 
   4623   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4624     return MCDisassembler::Fail;
   4625   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
   4626     return MCDisassembler::Fail;
   4627   Inst.addOperand(MCOperand::createImm(index));
   4628 
   4629   return S;
   4630 }
   4631 
   4632 static DecodeStatus DecodeVLD3LN(MCInst &Inst, unsigned Insn,
   4633                          uint64_t Address, const void *Decoder) {
   4634   DecodeStatus S = MCDisassembler::Success;
   4635 
   4636   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4637   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   4638   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   4639   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   4640   unsigned size = fieldFromInstruction(Insn, 10, 2);
   4641 
   4642   unsigned align = 0;
   4643   unsigned index = 0;
   4644   unsigned inc = 1;
   4645   switch (size) {
   4646     default:
   4647       return MCDisassembler::Fail;
   4648     case 0:
   4649       if (fieldFromInstruction(Insn, 4, 1))
   4650         return MCDisassembler::Fail; // UNDEFINED
   4651       index = fieldFromInstruction(Insn, 5, 3);
   4652       break;
   4653     case 1:
   4654       if (fieldFromInstruction(Insn, 4, 1))
   4655         return MCDisassembler::Fail; // UNDEFINED
   4656       index = fieldFromInstruction(Insn, 6, 2);
   4657       if (fieldFromInstruction(Insn, 5, 1))
   4658         inc = 2;
   4659       break;
   4660     case 2:
   4661       if (fieldFromInstruction(Insn, 4, 2))
   4662         return MCDisassembler::Fail; // UNDEFINED
   4663       index = fieldFromInstruction(Insn, 7, 1);
   4664       if (fieldFromInstruction(Insn, 6, 1))
   4665         inc = 2;
   4666       break;
   4667   }
   4668 
   4669   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4670     return MCDisassembler::Fail;
   4671   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
   4672     return MCDisassembler::Fail;
   4673   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
   4674     return MCDisassembler::Fail;
   4675 
   4676   if (Rm != 0xF) { // Writeback
   4677     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4678     return MCDisassembler::Fail;
   4679   }
   4680   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4681     return MCDisassembler::Fail;
   4682   Inst.addOperand(MCOperand::createImm(align));
   4683   if (Rm != 0xF) {
   4684     if (Rm != 0xD) {
   4685       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   4686     return MCDisassembler::Fail;
   4687     } else
   4688       Inst.addOperand(MCOperand::createReg(0));
   4689   }
   4690 
   4691   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4692     return MCDisassembler::Fail;
   4693   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
   4694     return MCDisassembler::Fail;
   4695   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
   4696     return MCDisassembler::Fail;
   4697   Inst.addOperand(MCOperand::createImm(index));
   4698 
   4699   return S;
   4700 }
   4701 
   4702 static DecodeStatus DecodeVST3LN(MCInst &Inst, unsigned Insn,
   4703                          uint64_t Address, const void *Decoder) {
   4704   DecodeStatus S = MCDisassembler::Success;
   4705 
   4706   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4707   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   4708   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   4709   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   4710   unsigned size = fieldFromInstruction(Insn, 10, 2);
   4711 
   4712   unsigned align = 0;
   4713   unsigned index = 0;
   4714   unsigned inc = 1;
   4715   switch (size) {
   4716     default:
   4717       return MCDisassembler::Fail;
   4718     case 0:
   4719       if (fieldFromInstruction(Insn, 4, 1))
   4720         return MCDisassembler::Fail; // UNDEFINED
   4721       index = fieldFromInstruction(Insn, 5, 3);
   4722       break;
   4723     case 1:
   4724       if (fieldFromInstruction(Insn, 4, 1))
   4725         return MCDisassembler::Fail; // UNDEFINED
   4726       index = fieldFromInstruction(Insn, 6, 2);
   4727       if (fieldFromInstruction(Insn, 5, 1))
   4728         inc = 2;
   4729       break;
   4730     case 2:
   4731       if (fieldFromInstruction(Insn, 4, 2))
   4732         return MCDisassembler::Fail; // UNDEFINED
   4733       index = fieldFromInstruction(Insn, 7, 1);
   4734       if (fieldFromInstruction(Insn, 6, 1))
   4735         inc = 2;
   4736       break;
   4737   }
   4738 
   4739   if (Rm != 0xF) { // Writeback
   4740     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4741     return MCDisassembler::Fail;
   4742   }
   4743   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4744     return MCDisassembler::Fail;
   4745   Inst.addOperand(MCOperand::createImm(align));
   4746   if (Rm != 0xF) {
   4747     if (Rm != 0xD) {
   4748       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   4749     return MCDisassembler::Fail;
   4750     } else
   4751       Inst.addOperand(MCOperand::createReg(0));
   4752   }
   4753 
   4754   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4755     return MCDisassembler::Fail;
   4756   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
   4757     return MCDisassembler::Fail;
   4758   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
   4759     return MCDisassembler::Fail;
   4760   Inst.addOperand(MCOperand::createImm(index));
   4761 
   4762   return S;
   4763 }
   4764 
   4765 static DecodeStatus DecodeVLD4LN(MCInst &Inst, unsigned Insn,
   4766                          uint64_t Address, const void *Decoder) {
   4767   DecodeStatus S = MCDisassembler::Success;
   4768 
   4769   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4770   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   4771   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   4772   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   4773   unsigned size = fieldFromInstruction(Insn, 10, 2);
   4774 
   4775   unsigned align = 0;
   4776   unsigned index = 0;
   4777   unsigned inc = 1;
   4778   switch (size) {
   4779     default:
   4780       return MCDisassembler::Fail;
   4781     case 0:
   4782       if (fieldFromInstruction(Insn, 4, 1))
   4783         align = 4;
   4784       index = fieldFromInstruction(Insn, 5, 3);
   4785       break;
   4786     case 1:
   4787       if (fieldFromInstruction(Insn, 4, 1))
   4788         align = 8;
   4789       index = fieldFromInstruction(Insn, 6, 2);
   4790       if (fieldFromInstruction(Insn, 5, 1))
   4791         inc = 2;
   4792       break;
   4793     case 2:
   4794       switch (fieldFromInstruction(Insn, 4, 2)) {
   4795         case 0:
   4796           align = 0; break;
   4797         case 3:
   4798           return MCDisassembler::Fail;
   4799         default:
   4800           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
   4801       }
   4802 
   4803       index = fieldFromInstruction(Insn, 7, 1);
   4804       if (fieldFromInstruction(Insn, 6, 1))
   4805         inc = 2;
   4806       break;
   4807   }
   4808 
   4809   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4810     return MCDisassembler::Fail;
   4811   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
   4812     return MCDisassembler::Fail;
   4813   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
   4814     return MCDisassembler::Fail;
   4815   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
   4816     return MCDisassembler::Fail;
   4817 
   4818   if (Rm != 0xF) { // Writeback
   4819     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4820       return MCDisassembler::Fail;
   4821   }
   4822   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4823     return MCDisassembler::Fail;
   4824   Inst.addOperand(MCOperand::createImm(align));
   4825   if (Rm != 0xF) {
   4826     if (Rm != 0xD) {
   4827       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   4828         return MCDisassembler::Fail;
   4829     } else
   4830       Inst.addOperand(MCOperand::createReg(0));
   4831   }
   4832 
   4833   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4834     return MCDisassembler::Fail;
   4835   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
   4836     return MCDisassembler::Fail;
   4837   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
   4838     return MCDisassembler::Fail;
   4839   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
   4840     return MCDisassembler::Fail;
   4841   Inst.addOperand(MCOperand::createImm(index));
   4842 
   4843   return S;
   4844 }
   4845 
   4846 static DecodeStatus DecodeVST4LN(MCInst &Inst, unsigned Insn,
   4847                          uint64_t Address, const void *Decoder) {
   4848   DecodeStatus S = MCDisassembler::Success;
   4849 
   4850   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4851   unsigned Rm = fieldFromInstruction(Insn, 0, 4);
   4852   unsigned Rd = fieldFromInstruction(Insn, 12, 4);
   4853   Rd |= fieldFromInstruction(Insn, 22, 1) << 4;
   4854   unsigned size = fieldFromInstruction(Insn, 10, 2);
   4855 
   4856   unsigned align = 0;
   4857   unsigned index = 0;
   4858   unsigned inc = 1;
   4859   switch (size) {
   4860     default:
   4861       return MCDisassembler::Fail;
   4862     case 0:
   4863       if (fieldFromInstruction(Insn, 4, 1))
   4864         align = 4;
   4865       index = fieldFromInstruction(Insn, 5, 3);
   4866       break;
   4867     case 1:
   4868       if (fieldFromInstruction(Insn, 4, 1))
   4869         align = 8;
   4870       index = fieldFromInstruction(Insn, 6, 2);
   4871       if (fieldFromInstruction(Insn, 5, 1))
   4872         inc = 2;
   4873       break;
   4874     case 2:
   4875       switch (fieldFromInstruction(Insn, 4, 2)) {
   4876         case 0:
   4877           align = 0; break;
   4878         case 3:
   4879           return MCDisassembler::Fail;
   4880         default:
   4881           align = 4 << fieldFromInstruction(Insn, 4, 2); break;
   4882       }
   4883 
   4884       index = fieldFromInstruction(Insn, 7, 1);
   4885       if (fieldFromInstruction(Insn, 6, 1))
   4886         inc = 2;
   4887       break;
   4888   }
   4889 
   4890   if (Rm != 0xF) { // Writeback
   4891     if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4892     return MCDisassembler::Fail;
   4893   }
   4894   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
   4895     return MCDisassembler::Fail;
   4896   Inst.addOperand(MCOperand::createImm(align));
   4897   if (Rm != 0xF) {
   4898     if (Rm != 0xD) {
   4899       if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
   4900     return MCDisassembler::Fail;
   4901     } else
   4902       Inst.addOperand(MCOperand::createReg(0));
   4903   }
   4904 
   4905   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
   4906     return MCDisassembler::Fail;
   4907   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)))
   4908     return MCDisassembler::Fail;
   4909   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)))
   4910     return MCDisassembler::Fail;
   4911   if (!Check(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)))
   4912     return MCDisassembler::Fail;
   4913   Inst.addOperand(MCOperand::createImm(index));
   4914 
   4915   return S;
   4916 }
   4917 
   4918 static DecodeStatus DecodeVMOVSRR(MCInst &Inst, unsigned Insn,
   4919                                   uint64_t Address, const void *Decoder) {
   4920   DecodeStatus S = MCDisassembler::Success;
   4921   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
   4922   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
   4923   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
   4924   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   4925   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
   4926 
   4927   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
   4928     S = MCDisassembler::SoftFail;
   4929 
   4930   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
   4931     return MCDisassembler::Fail;
   4932   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
   4933     return MCDisassembler::Fail;
   4934   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
   4935     return MCDisassembler::Fail;
   4936   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
   4937     return MCDisassembler::Fail;
   4938   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   4939     return MCDisassembler::Fail;
   4940 
   4941   return S;
   4942 }
   4943 
   4944 static DecodeStatus DecodeVMOVRRS(MCInst &Inst, unsigned Insn,
   4945                                   uint64_t Address, const void *Decoder) {
   4946   DecodeStatus S = MCDisassembler::Success;
   4947   unsigned Rt  = fieldFromInstruction(Insn, 12, 4);
   4948   unsigned Rt2 = fieldFromInstruction(Insn, 16, 4);
   4949   unsigned Rm  = fieldFromInstruction(Insn,  5, 1);
   4950   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   4951   Rm |= fieldFromInstruction(Insn, 0, 4) << 1;
   4952 
   4953   if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
   4954     S = MCDisassembler::SoftFail;
   4955 
   4956   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
   4957     return MCDisassembler::Fail;
   4958   if (!Check(S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
   4959     return MCDisassembler::Fail;
   4960   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
   4961     return MCDisassembler::Fail;
   4962   if (!Check(S, DecodeSPRRegisterClass(Inst, Rm+1, Address, Decoder)))
   4963     return MCDisassembler::Fail;
   4964   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   4965     return MCDisassembler::Fail;
   4966 
   4967   return S;
   4968 }
   4969 
   4970 static DecodeStatus DecodeIT(MCInst &Inst, unsigned Insn,
   4971                              uint64_t Address, const void *Decoder) {
   4972   DecodeStatus S = MCDisassembler::Success;
   4973   unsigned pred = fieldFromInstruction(Insn, 4, 4);
   4974   unsigned mask = fieldFromInstruction(Insn, 0, 4);
   4975 
   4976   if (pred == 0xF) {
   4977     pred = 0xE;
   4978     S = MCDisassembler::SoftFail;
   4979   }
   4980 
   4981   if (mask == 0x0)
   4982     return MCDisassembler::Fail;
   4983 
   4984   Inst.addOperand(MCOperand::createImm(pred));
   4985   Inst.addOperand(MCOperand::createImm(mask));
   4986   return S;
   4987 }
   4988 
   4989 static DecodeStatus
   4990 DecodeT2LDRDPreInstruction(MCInst &Inst, unsigned Insn,
   4991                            uint64_t Address, const void *Decoder) {
   4992   DecodeStatus S = MCDisassembler::Success;
   4993 
   4994   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   4995   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
   4996   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   4997   unsigned addr = fieldFromInstruction(Insn, 0, 8);
   4998   unsigned W = fieldFromInstruction(Insn, 21, 1);
   4999   unsigned U = fieldFromInstruction(Insn, 23, 1);
   5000   unsigned P = fieldFromInstruction(Insn, 24, 1);
   5001   bool writeback = (W == 1) | (P == 0);
   5002 
   5003   addr |= (U << 8) | (Rn << 9);
   5004 
   5005   if (writeback && (Rn == Rt || Rn == Rt2))
   5006     Check(S, MCDisassembler::SoftFail);
   5007   if (Rt == Rt2)
   5008     Check(S, MCDisassembler::SoftFail);
   5009 
   5010   // Rt
   5011   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
   5012     return MCDisassembler::Fail;
   5013   // Rt2
   5014   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
   5015     return MCDisassembler::Fail;
   5016   // Writeback operand
   5017   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
   5018     return MCDisassembler::Fail;
   5019   // addr
   5020   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
   5021     return MCDisassembler::Fail;
   5022 
   5023   return S;
   5024 }
   5025 
   5026 static DecodeStatus
   5027 DecodeT2STRDPreInstruction(MCInst &Inst, unsigned Insn,
   5028                            uint64_t Address, const void *Decoder) {
   5029   DecodeStatus S = MCDisassembler::Success;
   5030 
   5031   unsigned Rt = fieldFromInstruction(Insn, 12, 4);
   5032   unsigned Rt2 = fieldFromInstruction(Insn, 8, 4);
   5033   unsigned Rn = fieldFromInstruction(Insn, 16, 4);
   5034   unsigned addr = fieldFromInstruction(Insn, 0, 8);
   5035   unsigned W = fieldFromInstruction(Insn, 21, 1);
   5036   unsigned U = fieldFromInstruction(Insn, 23, 1);
   5037   unsigned P = fieldFromInstruction(Insn, 24, 1);
   5038   bool writeback = (W == 1) | (P == 0);
   5039 
   5040   addr |= (U << 8) | (Rn << 9);
   5041 
   5042   if (writeback && (Rn == Rt || Rn == Rt2))
   5043     Check(S, MCDisassembler::SoftFail);
   5044 
   5045   // Writeback operand
   5046   if (!Check(S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
   5047     return MCDisassembler::Fail;
   5048   // Rt
   5049   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
   5050     return MCDisassembler::Fail;
   5051   // Rt2
   5052   if (!Check(S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
   5053     return MCDisassembler::Fail;
   5054   // addr
   5055   if (!Check(S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
   5056     return MCDisassembler::Fail;
   5057 
   5058   return S;
   5059 }
   5060 
   5061 static DecodeStatus DecodeT2Adr(MCInst &Inst, uint32_t Insn,
   5062                                 uint64_t Address, const void *Decoder) {
   5063   unsigned sign1 = fieldFromInstruction(Insn, 21, 1);
   5064   unsigned sign2 = fieldFromInstruction(Insn, 23, 1);
   5065   if (sign1 != sign2) return MCDisassembler::Fail;
   5066 
   5067   unsigned Val = fieldFromInstruction(Insn, 0, 8);
   5068   Val |= fieldFromInstruction(Insn, 12, 3) << 8;
   5069   Val |= fieldFromInstruction(Insn, 26, 1) << 11;
   5070   Val |= sign1 << 12;
   5071   Inst.addOperand(MCOperand::createImm(SignExtend32<13>(Val)));
   5072 
   5073   return MCDisassembler::Success;
   5074 }
   5075 
   5076 static DecodeStatus DecodeT2ShifterImmOperand(MCInst &Inst, uint32_t Val,
   5077                                               uint64_t Address,
   5078                                               const void *Decoder) {
   5079   DecodeStatus S = MCDisassembler::Success;
   5080 
   5081   // Shift of "asr #32" is not allowed in Thumb2 mode.
   5082   if (Val == 0x20) S = MCDisassembler::Fail;
   5083   Inst.addOperand(MCOperand::createImm(Val));
   5084   return S;
   5085 }
   5086 
   5087 static DecodeStatus DecodeSwap(MCInst &Inst, unsigned Insn,
   5088                                uint64_t Address, const void *Decoder) {
   5089   unsigned Rt   = fieldFromInstruction(Insn, 12, 4);
   5090   unsigned Rt2  = fieldFromInstruction(Insn, 0,  4);
   5091   unsigned Rn   = fieldFromInstruction(Insn, 16, 4);
   5092   unsigned pred = fieldFromInstruction(Insn, 28, 4);
   5093 
   5094   if (pred == 0xF)
   5095     return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
   5096 
   5097   DecodeStatus S = MCDisassembler::Success;
   5098 
   5099   if (Rt == Rn || Rn == Rt2)
   5100     S = MCDisassembler::SoftFail;
   5101 
   5102   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
   5103     return MCDisassembler::Fail;
   5104   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
   5105     return MCDisassembler::Fail;
   5106   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
   5107     return MCDisassembler::Fail;
   5108   if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   5109     return MCDisassembler::Fail;
   5110 
   5111   return S;
   5112 }
   5113 
   5114 static DecodeStatus DecodeVCVTD(MCInst &Inst, unsigned Insn,
   5115                                 uint64_t Address, const void *Decoder) {
   5116   const FeatureBitset &featureBits =
   5117       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
   5118   bool hasFullFP16 = featureBits[ARM::FeatureFullFP16];
   5119 
   5120   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
   5121   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
   5122   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
   5123   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
   5124   unsigned imm = fieldFromInstruction(Insn, 16, 6);
   5125   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
   5126   unsigned op = fieldFromInstruction(Insn, 5, 1);
   5127 
   5128   DecodeStatus S = MCDisassembler::Success;
   5129 
   5130   // If the top 3 bits of imm are clear, this is a VMOV (immediate)
   5131   if (!(imm & 0x38)) {
   5132     if (cmode == 0xF) {
   5133       if (op == 1) return MCDisassembler::Fail;
   5134       Inst.setOpcode(ARM::VMOVv2f32);
   5135     }
   5136     if (hasFullFP16) {
   5137       if (cmode == 0xE) {
   5138         if (op == 1) {
   5139           Inst.setOpcode(ARM::VMOVv1i64);
   5140         } else {
   5141           Inst.setOpcode(ARM::VMOVv8i8);
   5142         }
   5143       }
   5144       if (cmode == 0xD) {
   5145         if (op == 1) {
   5146           Inst.setOpcode(ARM::VMVNv2i32);
   5147         } else {
   5148           Inst.setOpcode(ARM::VMOVv2i32);
   5149         }
   5150       }
   5151       if (cmode == 0xC) {
   5152         if (op == 1) {
   5153           Inst.setOpcode(ARM::VMVNv2i32);
   5154         } else {
   5155           Inst.setOpcode(ARM::VMOVv2i32);
   5156         }
   5157       }
   5158     }
   5159     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
   5160   }
   5161 
   5162   if (!(imm & 0x20)) return MCDisassembler::Fail;
   5163 
   5164   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
   5165     return MCDisassembler::Fail;
   5166   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
   5167     return MCDisassembler::Fail;
   5168   Inst.addOperand(MCOperand::createImm(64 - imm));
   5169 
   5170   return S;
   5171 }
   5172 
   5173 static DecodeStatus DecodeVCVTQ(MCInst &Inst, unsigned Insn,
   5174                                 uint64_t Address, const void *Decoder) {
   5175   const FeatureBitset &featureBits =
   5176       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
   5177   bool hasFullFP16 = featureBits[ARM::FeatureFullFP16];
   5178 
   5179   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
   5180   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
   5181   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
   5182   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
   5183   unsigned imm = fieldFromInstruction(Insn, 16, 6);
   5184   unsigned cmode = fieldFromInstruction(Insn, 8, 4);
   5185   unsigned op = fieldFromInstruction(Insn, 5, 1);
   5186 
   5187   DecodeStatus S = MCDisassembler::Success;
   5188 
   5189   // If the top 3 bits of imm are clear, this is a VMOV (immediate)
   5190   if (!(imm & 0x38)) {
   5191     if (cmode == 0xF) {
   5192       if (op == 1) return MCDisassembler::Fail;
   5193       Inst.setOpcode(ARM::VMOVv4f32);
   5194     }
   5195     if (hasFullFP16) {
   5196       if (cmode == 0xE) {
   5197         if (op == 1) {
   5198           Inst.setOpcode(ARM::VMOVv2i64);
   5199         } else {
   5200           Inst.setOpcode(ARM::VMOVv16i8);
   5201         }
   5202       }
   5203       if (cmode == 0xD) {
   5204         if (op == 1) {
   5205           Inst.setOpcode(ARM::VMVNv4i32);
   5206         } else {
   5207           Inst.setOpcode(ARM::VMOVv4i32);
   5208         }
   5209       }
   5210       if (cmode == 0xC) {
   5211         if (op == 1) {
   5212           Inst.setOpcode(ARM::VMVNv4i32);
   5213         } else {
   5214           Inst.setOpcode(ARM::VMOVv4i32);
   5215         }
   5216       }
   5217     }
   5218     return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
   5219   }
   5220 
   5221   if (!(imm & 0x20)) return MCDisassembler::Fail;
   5222 
   5223   if (!Check(S, DecodeQPRRegisterClass(Inst, Vd, Address, Decoder)))
   5224     return MCDisassembler::Fail;
   5225   if (!Check(S, DecodeQPRRegisterClass(Inst, Vm, Address, Decoder)))
   5226     return MCDisassembler::Fail;
   5227   Inst.addOperand(MCOperand::createImm(64 - imm));
   5228 
   5229   return S;
   5230 }
   5231 
   5232 static DecodeStatus DecodeNEONComplexLane64Instruction(MCInst &Inst,
   5233                                                        unsigned Insn,
   5234                                                        uint64_t Address,
   5235                                                        const void *Decoder) {
   5236   unsigned Vd = (fieldFromInstruction(Insn, 12, 4) << 0);
   5237   Vd |= (fieldFromInstruction(Insn, 22, 1) << 4);
   5238   unsigned Vn = (fieldFromInstruction(Insn, 16, 4) << 0);
   5239   Vn |= (fieldFromInstruction(Insn, 7, 1) << 4);
   5240   unsigned Vm = (fieldFromInstruction(Insn, 0, 4) << 0);
   5241   Vm |= (fieldFromInstruction(Insn, 5, 1) << 4);
   5242   unsigned q = (fieldFromInstruction(Insn, 6, 1) << 0);
   5243   unsigned rotate = (fieldFromInstruction(Insn, 20, 2) << 0);
   5244 
   5245   DecodeStatus S = MCDisassembler::Success;
   5246 
   5247   auto DestRegDecoder = q ? DecodeQPRRegisterClass : DecodeDPRRegisterClass;
   5248 
   5249   if (!Check(S, DestRegDecoder(Inst, Vd, Address, Decoder)))
   5250     return MCDisassembler::Fail;
   5251   if (!Check(S, DestRegDecoder(Inst, Vd, Address, Decoder)))
   5252     return MCDisassembler::Fail;
   5253   if (!Check(S, DestRegDecoder(Inst, Vn, Address, Decoder)))
   5254     return MCDisassembler::Fail;
   5255   if (!Check(S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
   5256     return MCDisassembler::Fail;
   5257   // The lane index does not have any bits in the encoding, because it can only
   5258   // be 0.
   5259   Inst.addOperand(MCOperand::createImm(0));
   5260   Inst.addOperand(MCOperand::createImm(rotate));
   5261 
   5262   return S;
   5263 }
   5264 
   5265 static DecodeStatus DecodeLDR(MCInst &Inst, unsigned Val,
   5266                                 uint64_t Address, const void *Decoder) {
   5267   DecodeStatus S = MCDisassembler::Success;
   5268 
   5269   unsigned Rn = fieldFromInstruction(Val, 16, 4);
   5270   unsigned Rt = fieldFromInstruction(Val, 12, 4);
   5271   unsigned Rm = fieldFromInstruction(Val, 0, 4);
   5272   Rm |= (fieldFromInstruction(Val, 23, 1) << 4);
   5273   unsigned Cond = fieldFromInstruction(Val, 28, 4);
   5274 
   5275   if (fieldFromInstruction(Val, 8, 4) != 0 || Rn == Rt)
   5276     S = MCDisassembler::SoftFail;
   5277 
   5278   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
   5279     return MCDisassembler::Fail;
   5280   if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
   5281     return MCDisassembler::Fail;
   5282   if (!Check(S, DecodeAddrMode7Operand(Inst, Rn, Address, Decoder)))
   5283     return MCDisassembler::Fail;
   5284   if (!Check(S, DecodePostIdxReg(Inst, Rm, Address, Decoder)))
   5285     return MCDisassembler::Fail;
   5286   if (!Check(S, DecodePredicateOperand(Inst, Cond, Address, Decoder)))
   5287     return MCDisassembler::Fail;
   5288 
   5289   return S;
   5290 }
   5291 
   5292 static DecodeStatus DecoderForMRRC2AndMCRR2(MCInst &Inst, unsigned Val,
   5293                                             uint64_t Address, const void *Decoder) {
   5294   DecodeStatus S = MCDisassembler::Success;
   5295 
   5296   unsigned CRm = fieldFromInstruction(Val, 0, 4);
   5297   unsigned opc1 = fieldFromInstruction(Val, 4, 4);
   5298   unsigned cop = fieldFromInstruction(Val, 8, 4);
   5299   unsigned Rt = fieldFromInstruction(Val, 12, 4);
   5300   unsigned Rt2 = fieldFromInstruction(Val, 16, 4);
   5301 
   5302   if ((cop & ~0x1) == 0xa)
   5303     return MCDisassembler::Fail;
   5304 
   5305   if (Rt == Rt2)
   5306     S = MCDisassembler::SoftFail;
   5307 
   5308   // We have to check if the instruction is MRRC2
   5309   // or MCRR2 when constructing the operands for
   5310   // Inst. Reason is because MRRC2 stores to two
   5311   // registers so it's tablegen desc has has two
   5312   // outputs whereas MCRR doesn't store to any
   5313   // registers so all of it's operands are listed
   5314   // as inputs, therefore the operand order for
   5315   // MRRC2 needs to be [Rt, Rt2, cop, opc1, CRm]
   5316   // and MCRR2 operand order is [cop, opc1, Rt, Rt2, CRm]
   5317 
   5318   if (Inst.getOpcode() == ARM::MRRC2) {
   5319     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
   5320       return MCDisassembler::Fail;
   5321     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
   5322       return MCDisassembler::Fail;
   5323   }
   5324   Inst.addOperand(MCOperand::createImm(cop));
   5325   Inst.addOperand(MCOperand::createImm(opc1));
   5326   if (Inst.getOpcode() == ARM::MCRR2) {
   5327     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
   5328       return MCDisassembler::Fail;
   5329     if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
   5330       return MCDisassembler::Fail;
   5331   }
   5332   Inst.addOperand(MCOperand::createImm(CRm));
   5333 
   5334   return S;
   5335 }
   5336 
   5337 static DecodeStatus DecodeForVMRSandVMSR(MCInst &Inst, unsigned Val,
   5338                                          uint64_t Address,
   5339                                          const void *Decoder) {
   5340   const FeatureBitset &featureBits =
   5341       ((const MCDisassembler *)Decoder)->getSubtargetInfo().getFeatureBits();
   5342   DecodeStatus S = MCDisassembler::Success;
   5343 
   5344   unsigned Rt = fieldFromInstruction(Val, 12, 4);
   5345 
   5346   if (featureBits[ARM::ModeThumb] && !featureBits[ARM::HasV8Ops]) {
   5347     if (Rt == 13 || Rt == 15)
   5348       S = MCDisassembler::SoftFail;
   5349     Check(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
   5350   } else
   5351     Check(S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder));
   5352 
   5353   if (featureBits[ARM::ModeThumb]) {
   5354     Inst.addOperand(MCOperand::createImm(ARMCC::AL));
   5355     Inst.addOperand(MCOperand::createReg(0));
   5356   } else {
   5357     unsigned pred = fieldFromInstruction(Val, 28, 4);
   5358     if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
   5359       return MCDisassembler::Fail;
   5360   }
   5361 
   5362   return S;
   5363 }
   5364