/src/capstonev5/arch/ARM/ARMDisassembler.c

Source (jump to first uncovered line)
//===-- ARMDisassembler.cpp - Disassembler for ARM/Thumb ISA --------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

/* Capstone Disassembly Engine */
/* By Nguyen Anh Quynh <aquynh@gmail.com>, 2013-2019 */

#ifdef CAPSTONE_HAS_ARM

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <capstone/platform.h>

#include "ARMAddressingModes.h"
#include "ARMBaseInfo.h"
#include "../../MCFixedLenDisassembler.h"
#include "../../MCInst.h"
#include "../../MCInstrDesc.h"
#include "../../MCRegisterInfo.h"
#include "../../LEB128.h"
#include "../../MCDisassembler.h"
#include "../../cs_priv.h"
#include "../../utils.h"

#include "ARMDisassembler.h"
#include "ARMMapping.h"

#define GET_SUBTARGETINFO_ENUM
#include "ARMGenSubtargetInfo.inc"

#define GET_INSTRINFO_MC_DESC
#include "ARMGenInstrInfo.inc"

#define GET_INSTRINFO_ENUM
#include "ARMGenInstrInfo.inc"

static bool ITStatus_push_back(ARM_ITStatus *it, char v)
{
  if (it->size >= sizeof(it->ITStates)) {
    // TODO: consider warning user.
    it->size = 0;
  }
  it->ITStates[it->size] = v;
  it->size++;

  return true;
}

// Returns true if the current instruction is in an IT block
static bool ITStatus_instrInITBlock(ARM_ITStatus *it)
{
  //return !ITStates.empty();
  return (it->size > 0);
}

// Returns true if current instruction is the last instruction in an IT block
static bool ITStatus_instrLastInITBlock(ARM_ITStatus *it)
{
  return (it->size == 1);
}

// Handles the condition code status of instructions in IT blocks

// Returns the condition code for instruction in IT block
static unsigned ITStatus_getITCC(ARM_ITStatus *it)
{
  unsigned CC = ARMCC_AL;

  if (ITStatus_instrInITBlock(it))
    //CC = ITStates.back();
    CC = it->ITStates[it->size-1];

  return CC;
}

// Advances the IT block state to the next T or E
static void ITStatus_advanceITState(ARM_ITStatus *it)
{
  //ITStates.pop_back();
  it->size--;
}

// Called when decoding an IT instruction. Sets the IT state for the following
// instructions that for the IT block. Firstcond and Mask correspond to the 
// fields in the IT instruction encoding.
static void ITStatus_setITState(ARM_ITStatus *it, char Firstcond, char Mask)
{
  // (3 - the number of trailing zeros) is the number of then / else.
  unsigned CondBit0 = Firstcond & 1;
  unsigned NumTZ = CountTrailingZeros_32(Mask);
  unsigned char CCBits = (unsigned char)Firstcond & 0xf;
  unsigned Pos;

  //assert(NumTZ <= 3 && "Invalid IT mask!");
  // push condition codes onto the stack the correct order for the pops
  for (Pos = NumTZ + 1; Pos <= 3; ++Pos) {
    bool T = ((Mask >> Pos) & 1) == (int)CondBit0;

    if (T)
      ITStatus_push_back(it, CCBits);
    else
      ITStatus_push_back(it, CCBits ^ 1);
  }

  ITStatus_push_back(it, CCBits);
}

/// ThumbDisassembler - Thumb disassembler for all Thumb platforms.

static bool Check(DecodeStatus *Out, DecodeStatus In)
{
  switch (In) {
    case MCDisassembler_Success:
      // Out stays the same.
      return true;
    case MCDisassembler_SoftFail:
      *Out = In;
      return true;
    case MCDisassembler_Fail:
      *Out = In;
      return false;
    default:  // never reached
      return false;
  }
}

// Forward declare these because the autogenerated code will reference them.
// Definitions are further down.
static DecodeStatus DecodeGPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeGPRnopcRegisterClass(MCInst *Inst,
    unsigned RegNo, uint64_t Address, const void *Decoder);
static DecodeStatus DecodeGPRwithAPSRRegisterClass(MCInst *Inst,
    unsigned RegNo, uint64_t Address, const void *Decoder);
static DecodeStatus DecodetGPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodetcGPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecoderGPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeGPRPairRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeSPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeDPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeDPR_8RegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeDPR_VFP2RegisterClass(MCInst *Inst,
    unsigned RegNo, uint64_t Address, const void *Decoder);
static DecodeStatus DecodeQPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeDPairRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst *Inst,
    unsigned RegNo, uint64_t Address, const void *Decoder);
static DecodeStatus DecodePredicateOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeCCOutOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeRegListOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeSPRRegListOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeDPRRegListOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeBitfieldMaskOperand(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeCopMemInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeAddrMode2IdxInstruction(MCInst *Inst,
    unsigned Insn, uint64_t Address, const void *Decoder);
static DecodeStatus DecodeSORegMemOperand(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeAddrMode3Instruction(MCInst *Inst,unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeSORegImmOperand(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeSORegRegOperand(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst * Inst,
    unsigned Insn, uint64_t Adddress, const void *Decoder);
static DecodeStatus DecodeT2MOVTWInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeArmMOVTWInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeSMLAInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeCPSInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2CPSInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeAddrModeImm12Operand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeAddrMode5Operand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeAddrMode7Operand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2BInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeBranchImmInstruction(MCInst *Inst,unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeAddrMode6Operand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLDST1Instruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLDST2Instruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLDST3Instruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLDST4Instruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLDInstruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVSTInstruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLD1DupInstruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLD2DupInstruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLD3DupInstruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLD4DupInstruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeNEONModImmInstruction(MCInst *Inst,unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVSHLMaxInstruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeShiftRight8Imm(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeShiftRight16Imm(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeShiftRight32Imm(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeShiftRight64Imm(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeTBLInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodePostIdxReg(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeCoprocessor(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeMemBarrierOption(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeInstSyncBarrierOption(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeMSRMask(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeBankedReg(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeDoubleRegLoad(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeDoubleRegStore(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeLDRPreImm(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeLDRPreReg(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeSTRPreImm(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeSTRPreReg(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLD1LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLD2LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLD3LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVLD4LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVST1LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVST2LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVST3LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVST4LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVMOVSRR(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVMOVRRS(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeSwap(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVCVTD(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeVCVTQ(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbAddSpecialReg(MCInst *Inst, uint16_t Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbBROperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2BROperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbCmpBROperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbAddrModeRR(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbAddrModeIS(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbAddrModePC(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbAddrModeSP(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2AddrModeSOReg(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2LoadShift(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2LoadImm8(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void* Decoder);
static DecodeStatus DecodeT2LoadImm12(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void* Decoder);
static DecodeStatus DecodeT2LoadT(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void* Decoder);
static DecodeStatus DecodeT2LoadLabel(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void* Decoder);
static DecodeStatus DecodeT2Imm8S4(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2AddrModeImm8s4(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst *Inst,unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2Imm8(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2AddrModeImm8(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbAddSPImm(MCInst *Inst, uint16_t Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbAddSPReg(MCInst *Inst, uint16_t Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbCPS(MCInst *Inst, uint16_t Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeQADDInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbBLXOffset(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2AddrModeImm12(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbTableBranch(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumb2BCCInstruction(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2SOImm(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbBCCTargetOperand(MCInst *Inst,unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbBLTargetOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeIT(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2LDRDPreInstruction(MCInst *Inst,unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2STRDPreInstruction(MCInst *Inst,unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2Adr(MCInst *Inst, uint32_t Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2LdStPre(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2ShifterImmOperand(MCInst *Inst, uint32_t Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeLDR(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecoderForMRRC2AndMCRR2(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeHINTInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeTSTInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeSETPANInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeAddrMode5FP16Operand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeForVMRSandVMSR(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeNEONComplexLane64Instruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder);
static DecodeStatus DecodeHPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder);

// Hacky: enable all features for disassembler
bool ARM_getFeatureBits(unsigned int mode, unsigned int feature)
{
  if ((mode & CS_MODE_V8) == 0) {
    // not V8 mode
    if (feature == ARM_HasV8Ops || feature == ARM_HasV8_1aOps ||
      feature == ARM_HasV8_4aOps || feature == ARM_HasV8_3aOps)
      // HasV8MBaselineOps
      return false;
  }
  if (feature == ARM_FeatureVFPOnlySP)
    return false;

  if ((mode & CS_MODE_MCLASS) == 0) {
    if (feature == ARM_FeatureMClass)
      return false;
  }

  if ((mode & CS_MODE_THUMB) == 0) {
    // not Thumb
    if (feature == ARM_FeatureThumb2 || feature == ARM_ModeThumb)
      return false;
    // FIXME: what mode enables D16?
    if (feature == ARM_FeatureD16)
      return false;
  } else {
    // Thumb
    if (feature == ARM_FeatureD16)
      return false;
  }

  if (feature == ARM_FeatureMClass && (mode & CS_MODE_MCLASS) == 0)
    return false;

  // we support everything
  return true;
}

#include "ARMGenDisassemblerTables.inc"

static DecodeStatus DecodePredicateOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  if (Val == 0xF) return MCDisassembler_Fail;

  // AL predicate is not allowed on Thumb1 branches.
  if (MCInst_getOpcode(Inst) == ARM_tBcc && Val == 0xE)
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, Val);

  if (Val == ARMCC_AL) {
    MCOperand_CreateReg0(Inst, 0);
  } else
    MCOperand_CreateReg0(Inst, ARM_CPSR);

  return MCDisassembler_Success;
}

#define GET_REGINFO_MC_DESC
#include "ARMGenRegisterInfo.inc"
void ARM_init(MCRegisterInfo *MRI)
{
  /* 
    InitMCRegisterInfo(ARMRegDesc, 289,
    RA, PC,
    ARMMCRegisterClasses, 103,
    ARMRegUnitRoots, 77, ARMRegDiffLists, ARMRegStrings,
    ARMSubRegIdxLists, 57,
    ARMSubRegIdxRanges, ARMRegEncodingTable);
   */

  MCRegisterInfo_InitMCRegisterInfo(MRI, ARMRegDesc, 289,
      0, 0, 
      ARMMCRegisterClasses, 103,
      0, 0, ARMRegDiffLists, 0, 
      ARMSubRegIdxLists, 57,
      0);
}

// Post-decoding checks
static DecodeStatus checkDecodedInstruction(MCInst *MI,
    uint32_t Insn,
    DecodeStatus Result)
{
  switch (MCInst_getOpcode(MI)) {
    case ARM_HVC: {
        // HVC is undefined if condition = 0xf otherwise upredictable
        // if condition != 0xe
        uint32_t Cond = (Insn >> 28) & 0xF;

        if (Cond == 0xF)
          return MCDisassembler_Fail;

        if (Cond != 0xE)
          return MCDisassembler_SoftFail;

        return Result;
      }
    default:
         return Result;
  }
}

static DecodeStatus _ARM_getInstruction(cs_struct *ud, MCInst *MI, const uint8_t *code, size_t code_len,
    uint16_t *Size, uint64_t Address)
{
  uint32_t insn;
  DecodeStatus result;

  *Size = 0;

  if (code_len < 4)
    // not enough data
    return MCDisassembler_Fail;

  if (MI->flat_insn->detail) {
    unsigned int i;

    memset(MI->flat_insn->detail, 0, offsetof(cs_detail, arm) + sizeof(cs_arm));

    for (i = 0; i < ARR_SIZE(MI->flat_insn->detail->arm.operands); i++) {
      MI->flat_insn->detail->arm.operands[i].vector_index = -1;
      MI->flat_insn->detail->arm.operands[i].neon_lane = -1;
    }
  }

  if (MODE_IS_BIG_ENDIAN(ud->mode))
    insn = (code[3] << 0) | (code[2] << 8) |
      (code[1] <<  16) | ((uint32_t) code[0] << 24);
  else
    insn = ((uint32_t) code[3] << 24) | (code[2] << 16) |
      (code[1] <<  8) | (code[0] <<  0);

  // Calling the auto-generated decoder function.
  result = decodeInstruction_4(DecoderTableARM32, MI, insn, Address);
  if (result != MCDisassembler_Fail) {
    result = checkDecodedInstruction(MI, insn, result);
    if (result != MCDisassembler_Fail)
      *Size = 4;

    return result;
  }

  // VFP and NEON instructions, similarly, are shared between ARM
  // and Thumb modes.
  MCInst_clear(MI);
  result = decodeInstruction_4(DecoderTableVFP32, MI, insn, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    return result;
  }

  MCInst_clear(MI);
  result = decodeInstruction_4(DecoderTableVFPV832, MI, insn, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    return result;
  }

  MCInst_clear(MI);
  result = decodeInstruction_4(DecoderTableNEONData32, MI, insn, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    // Add a fake predicate operand, because we share these instruction
    // definitions with Thumb2 where these instructions are predicable.
    if (!DecodePredicateOperand(MI, 0xE, Address, NULL))
      return MCDisassembler_Fail;
    return result;
  }

  MCInst_clear(MI);
  result = decodeInstruction_4(DecoderTableNEONLoadStore32, MI, insn, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    // Add a fake predicate operand, because we share these instruction
    // definitions with Thumb2 where these instructions are predicable.
    if (!DecodePredicateOperand(MI, 0xE, Address, NULL))
      return MCDisassembler_Fail;
    return result;
  }

  MCInst_clear(MI);
  result = decodeInstruction_4(DecoderTableNEONDup32, MI, insn, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    // Add a fake predicate operand, because we share these instruction
    // definitions with Thumb2 where these instructions are predicable.
    if (!DecodePredicateOperand(MI, 0xE, Address, NULL))
      return MCDisassembler_Fail;
    return result;
  }

  MCInst_clear(MI);
  result = decodeInstruction_4(DecoderTablev8NEON32, MI, insn, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    return result;
  }

  MCInst_clear(MI);
  result = decodeInstruction_4(DecoderTablev8Crypto32, MI, insn, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    return result;
  }

  result = decodeInstruction_4(DecoderTableCoProc32, MI, insn, Address);
  if (result != MCDisassembler_Fail) {
    result = checkDecodedInstruction(MI, insn, result);
    if (result != MCDisassembler_Fail)
      *Size = 4;

    return result;
  }

  MCInst_clear(MI);
  *Size = 0;
  return MCDisassembler_Fail;
}

// Thumb1 instructions don't have explicit S bits. Rather, they
// implicitly set CPSR. Since it's not represented in the encoding, the
// auto-generated decoder won't inject the CPSR operand. We need to fix
// that as a post-pass.
static void AddThumb1SBit(MCInst *MI, bool InITBlock)
{
  const MCOperandInfo *OpInfo = ARMInsts[MCInst_getOpcode(MI)].OpInfo;
  unsigned short NumOps = ARMInsts[MCInst_getOpcode(MI)].NumOperands;
  unsigned i;

  for (i = 0; i < NumOps; ++i) {
    if (i == MCInst_getNumOperands(MI)) break;

    if (MCOperandInfo_isOptionalDef(&OpInfo[i]) && OpInfo[i].RegClass == ARM_CCRRegClassID) {
      if (i > 0 && MCOperandInfo_isPredicate(&OpInfo[i - 1])) continue;
      MCInst_insert0(MI, i, MCOperand_CreateReg1(MI, InITBlock ? 0 : ARM_CPSR));
      return;
    }
  }

  //MI.insert(I, MCOperand_CreateReg0(Inst, InITBlock ? 0 : ARM_CPSR));
  MCInst_insert0(MI, i, MCOperand_CreateReg1(MI, InITBlock ? 0 : ARM_CPSR));
}

// Most Thumb instructions don't have explicit predicates in the
// encoding, but rather get their predicates from IT context. We need
// to fix up the predicate operands using this context information as a
// post-pass.
static DecodeStatus AddThumbPredicate(cs_struct *ud, MCInst *MI)
{
  DecodeStatus S = MCDisassembler_Success;
  const MCOperandInfo *OpInfo;
  unsigned short NumOps;
  unsigned int i;
  unsigned CC;

  // A few instructions actually have predicates encoded in them. Don't
  // try to overwrite it if we're seeing one of those.
  switch (MCInst_getOpcode(MI)) {
    case ARM_tBcc:
    case ARM_t2Bcc:
    case ARM_tCBZ:
    case ARM_tCBNZ:
    case ARM_tCPS:
    case ARM_t2CPS3p:
    case ARM_t2CPS2p:
    case ARM_t2CPS1p:
    case ARM_tMOVSr:
    case ARM_tSETEND:
      // Some instructions (mostly conditional branches) are not
      // allowed in IT blocks.
      if (ITStatus_instrInITBlock(&(ud->ITBlock)))
        S = MCDisassembler_SoftFail;
      else
        return MCDisassembler_Success;
      break;

    case ARM_t2HINT:
      if (MCOperand_getImm(MCInst_getOperand(MI, 0)) == 0x10)
        S = MCDisassembler_SoftFail;
      break;

    case ARM_tB:
    case ARM_t2B:
    case ARM_t2TBB:
    case ARM_t2TBH:
      // Some instructions (mostly unconditional branches) can
      // only appears at the end of, or outside of, an IT.
      // if (ITBlock.instrInITBlock() && !ITBlock.instrLastInITBlock())
      if (ITStatus_instrInITBlock(&(ud->ITBlock)) && !ITStatus_instrLastInITBlock(&(ud->ITBlock)))
        S = MCDisassembler_SoftFail;
      break;
    default:
      break;
  }

  // If we're in an IT block, base the predicate on that.  Otherwise,
  // assume a predicate of AL.
  CC = ITStatus_getITCC(&(ud->ITBlock));
  if (CC == 0xF) 
    CC = ARMCC_AL;

  if (ITStatus_instrInITBlock(&(ud->ITBlock)))
    ITStatus_advanceITState(&(ud->ITBlock));

  OpInfo = ARMInsts[MCInst_getOpcode(MI)].OpInfo;
  NumOps = ARMInsts[MCInst_getOpcode(MI)].NumOperands;

  for (i = 0; i < NumOps; ++i) {
    if (i == MCInst_getNumOperands(MI)) break;

    if (MCOperandInfo_isPredicate(&OpInfo[i])) {
      MCInst_insert0(MI, i, MCOperand_CreateImm1(MI, CC));

      if (CC == ARMCC_AL)
        MCInst_insert0(MI, i+1, MCOperand_CreateReg1(MI, 0));
      else
        MCInst_insert0(MI, i+1, MCOperand_CreateReg1(MI, ARM_CPSR));

      return S;
    }
  }

  MCInst_insert0(MI, i, MCOperand_CreateImm1(MI, CC));

  if (CC == ARMCC_AL)
    MCInst_insert0(MI, i + 1, MCOperand_CreateReg1(MI, 0));
  else
    MCInst_insert0(MI, i + 1, MCOperand_CreateReg1(MI, ARM_CPSR));

  return S;
}

// Thumb VFP instructions are a special case. Because we share their
// encodings between ARM and Thumb modes, and they are predicable in ARM
// mode, the auto-generated decoder will give them an (incorrect)
// predicate operand. We need to rewrite these operands based on the IT
// context as a post-pass.
static void UpdateThumbVFPPredicate(cs_struct *ud, MCInst *MI)
{
  unsigned CC;
  unsigned short NumOps;
  const MCOperandInfo *OpInfo;
  unsigned i;

  CC = ITStatus_getITCC(&(ud->ITBlock));
  if (ITStatus_instrInITBlock(&(ud->ITBlock)))
    ITStatus_advanceITState(&(ud->ITBlock));

  OpInfo = ARMInsts[MCInst_getOpcode(MI)].OpInfo;
  NumOps = ARMInsts[MCInst_getOpcode(MI)].NumOperands;

  for (i = 0; i < NumOps; ++i) {
    if (MCOperandInfo_isPredicate(&OpInfo[i])) {
      MCOperand_setImm(MCInst_getOperand(MI, i), CC);

      if (CC == ARMCC_AL)
        MCOperand_setReg(MCInst_getOperand(MI, i + 1), 0);
      else
        MCOperand_setReg(MCInst_getOperand(MI, i + 1), ARM_CPSR);

      return;
    }
  }
}

static DecodeStatus _Thumb_getInstruction(cs_struct *ud, MCInst *MI, const uint8_t *code, size_t code_len,
    uint16_t *Size, uint64_t Address)
{
  uint16_t insn16;
  DecodeStatus result;
  bool InITBlock;
  unsigned Firstcond, Mask; 
  uint32_t NEONLdStInsn, insn32, NEONDataInsn, NEONCryptoInsn, NEONv8Insn;
  size_t i;

  // We want to read exactly 2 bytes of data.
  if (code_len < 2)
    // not enough data
    return MCDisassembler_Fail;

  if (MI->flat_insn->detail) {
    memset(MI->flat_insn->detail, 0, offsetof(cs_detail, arm)+sizeof(cs_arm));
    for (i = 0; i < ARR_SIZE(MI->flat_insn->detail->arm.operands); i++) {
      MI->flat_insn->detail->arm.operands[i].vector_index = -1;
      MI->flat_insn->detail->arm.operands[i].neon_lane = -1;
    }
  }

  if (MODE_IS_BIG_ENDIAN(ud->mode))
    insn16 = (code[0] << 8) | code[1];
  else
    insn16 = (code[1] << 8) | code[0];

  result = decodeInstruction_2(DecoderTableThumb16, MI, insn16, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 2;
    Check(&result, AddThumbPredicate(ud, MI));
    return result;
  }

  MCInst_clear(MI);
  result = decodeInstruction_2(DecoderTableThumbSBit16, MI, insn16, Address);
  if (result) {
    *Size = 2;
    InITBlock = ITStatus_instrInITBlock(&(ud->ITBlock));
    Check(&result, AddThumbPredicate(ud, MI));
    AddThumb1SBit(MI, InITBlock);
    return result;
  }

  MCInst_clear(MI);
  result = decodeInstruction_2(DecoderTableThumb216, MI, insn16, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 2;

    // Nested IT blocks are UNPREDICTABLE.  Must be checked before we add
    // the Thumb predicate.
    if (MCInst_getOpcode(MI) == ARM_t2IT && ITStatus_instrInITBlock(&(ud->ITBlock)))
      return MCDisassembler_SoftFail;

    Check(&result, AddThumbPredicate(ud, MI));

    // If we find an IT instruction, we need to parse its condition
    // code and mask operands so that we can apply them correctly
    // to the subsequent instructions.
    if (MCInst_getOpcode(MI) == ARM_t2IT) {
      Firstcond = (unsigned int)MCOperand_getImm(MCInst_getOperand(MI, 0));
      Mask = (unsigned int)MCOperand_getImm(MCInst_getOperand(MI, 1));
      ITStatus_setITState(&(ud->ITBlock), (char)Firstcond, (char)Mask);

      // An IT instruction that would give a 'NV' predicate is unpredictable.
      // if (Firstcond == ARMCC_AL && !isPowerOf2_32(Mask))
      //  CS << "unpredictable IT predicate sequence";
    }

    return result;
  }

  // We want to read exactly 4 bytes of data.
  if (code_len < 4)
    // not enough data
    return MCDisassembler_Fail;

  if (MODE_IS_BIG_ENDIAN(ud->mode))
    insn32 = (code[3] <<  0) | (code[2] <<  8) |
      (code[1] << 16) | ((uint32_t) code[0] << 24);
  else
    insn32 = (code[3] <<  8) | (code[2] <<  0) |
      ((uint32_t) code[1] << 24) | (code[0] << 16);

  MCInst_clear(MI);
  result = decodeInstruction_4(DecoderTableThumb32, MI, insn32, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    InITBlock = ITStatus_instrInITBlock(&(ud->ITBlock));
    Check(&result, AddThumbPredicate(ud, MI));
    AddThumb1SBit(MI, InITBlock);

    return result;
  }

  MCInst_clear(MI);
  result = decodeInstruction_4(DecoderTableThumb232, MI, insn32, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    Check(&result, AddThumbPredicate(ud, MI));
    return result;
  }

  if (fieldFromInstruction_4(insn32, 28, 4) == 0xE) {
    MCInst_clear(MI);
    result = decodeInstruction_4(DecoderTableVFP32, MI, insn32, Address);
    if (result != MCDisassembler_Fail) {
      *Size = 4;
      UpdateThumbVFPPredicate(ud, MI);
      return result;
    }
  }

  MCInst_clear(MI);
  result = decodeInstruction_4(DecoderTableVFPV832, MI, insn32, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    return result;
  }

  if (fieldFromInstruction_4(insn32, 28, 4) == 0xE) {
    MCInst_clear(MI);
    result = decodeInstruction_4(DecoderTableNEONDup32, MI, insn32, Address);
    if (result != MCDisassembler_Fail) {
      *Size = 4;
      Check(&result, AddThumbPredicate(ud, MI));
      return result;
    }
  }

  if (fieldFromInstruction_4(insn32, 24, 8) == 0xF9) {
    MCInst_clear(MI);
    NEONLdStInsn = insn32;
    NEONLdStInsn &= 0xF0FFFFFF;
    NEONLdStInsn |= 0x04000000;
    result = decodeInstruction_4(DecoderTableNEONLoadStore32, MI, NEONLdStInsn, Address);
    if (result != MCDisassembler_Fail) {
      *Size = 4;
      Check(&result, AddThumbPredicate(ud, MI));
      return result;
    }
  }

  if (fieldFromInstruction_4(insn32, 24, 4) == 0xF) {
    MCInst_clear(MI);
    NEONDataInsn = insn32;
    NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
    NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
    NEONDataInsn |= 0x12000000; // Set bits 28 and 25
    result = decodeInstruction_4(DecoderTableNEONData32, MI, NEONDataInsn, Address);
    if (result != MCDisassembler_Fail) {
      *Size = 4;
      Check(&result, AddThumbPredicate(ud, MI));
      return result;
    }
  }

  MCInst_clear(MI);
  NEONCryptoInsn = insn32;
  NEONCryptoInsn &= 0xF0FFFFFF; // Clear bits 27-24
  NEONCryptoInsn |= (NEONCryptoInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
  NEONCryptoInsn |= 0x12000000; // Set bits 28 and 25
  result = decodeInstruction_4(DecoderTablev8Crypto32, MI, NEONCryptoInsn, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    return result;
  }

  MCInst_clear(MI);
  NEONv8Insn = insn32;
  NEONv8Insn &= 0xF3FFFFFF; // Clear bits 27-26
  result = decodeInstruction_4(DecoderTablev8NEON32, MI, NEONv8Insn, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    return result;
  }

  MCInst_clear(MI);
  result = decodeInstruction_4(DecoderTableThumb2CoProc32, MI, insn32, Address);
  if (result != MCDisassembler_Fail) {
    *Size = 4;
    Check(&result, AddThumbPredicate(ud, MI));
    return result;
  }

  MCInst_clear(MI);
  *Size = 0;

  return MCDisassembler_Fail;
}

bool Thumb_getInstruction(csh ud, const uint8_t *code, size_t code_len, MCInst *instr,
    uint16_t *size, uint64_t address, void *info)
{
  DecodeStatus status = _Thumb_getInstruction((cs_struct *)ud, instr, code, code_len, size, address);

  // TODO: fix table gen to eliminate these special cases
  if (instr->Opcode == ARM_t__brkdiv0)
    return false;

  //return status == MCDisassembler_Success;
  return status != MCDisassembler_Fail;
}

bool ARM_getInstruction(csh ud, const uint8_t *code, size_t code_len, MCInst *instr,
    uint16_t *size, uint64_t address, void *info)
{
  DecodeStatus status = _ARM_getInstruction((cs_struct *)ud, instr, code, code_len, size, address);

  //return status == MCDisassembler_Success;
  return status != MCDisassembler_Fail;
}

static const uint16_t GPRDecoderTable[] = {
  ARM_R0, ARM_R1, ARM_R2, ARM_R3,
  ARM_R4, ARM_R5, ARM_R6, ARM_R7,
  ARM_R8, ARM_R9, ARM_R10, ARM_R11,
  ARM_R12, ARM_SP, ARM_LR, ARM_PC
};

static DecodeStatus DecodeGPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  unsigned Register;

  if (RegNo > 15)
    return MCDisassembler_Fail;

  Register = GPRDecoderTable[RegNo];
  MCOperand_CreateReg0(Inst, Register);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeGPRnopcRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  if (RegNo == 15) 
    S = MCDisassembler_SoftFail;

  Check(&S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));

  return S;
}

static DecodeStatus DecodeGPRwithAPSRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  if (RegNo == 15) {
    MCOperand_CreateReg0(Inst, ARM_APSR_NZCV);

    return MCDisassembler_Success;
  }

  Check(&S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
  return S;
}

static DecodeStatus DecodetGPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  if (RegNo > 7)
    return MCDisassembler_Fail;

  return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
}

static const uint16_t GPRPairDecoderTable[] = {
  ARM_R0_R1, ARM_R2_R3,   ARM_R4_R5,  ARM_R6_R7,
  ARM_R8_R9, ARM_R10_R11, ARM_R12_SP
};

static DecodeStatus DecodeGPRPairRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  unsigned RegisterPair;
  DecodeStatus S = MCDisassembler_Success;

  if (RegNo > 13)
    return MCDisassembler_Fail;

  if ((RegNo & 1) || RegNo == 0xe)
    S = MCDisassembler_SoftFail;

  RegisterPair = GPRPairDecoderTable[RegNo / 2];
  MCOperand_CreateReg0(Inst, RegisterPair);

  return S;
}

static DecodeStatus DecodetcGPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  unsigned Register = 0;

  switch (RegNo) {
    case 0:
      Register = ARM_R0;
      break;
    case 1:
      Register = ARM_R1;
      break;
    case 2:
      Register = ARM_R2;
      break;
    case 3:
      Register = ARM_R3;
      break;
    case 9:
      Register = ARM_R9;
      break;
    case 12:
      Register = ARM_R12;
      break;
    default:
      return MCDisassembler_Fail;
  }

  MCOperand_CreateReg0(Inst, Register);

  return MCDisassembler_Success;
}

static DecodeStatus DecoderGPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  if ((RegNo == 13 && !ARM_getFeatureBits(Inst->csh->mode, ARM_HasV8Ops)) || RegNo == 15)
    S = MCDisassembler_SoftFail;

  Check(&S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));

  return S;
}

static const uint16_t SPRDecoderTable[] = {
  ARM_S0,  ARM_S1,  ARM_S2,  ARM_S3,
  ARM_S4,  ARM_S5,  ARM_S6,  ARM_S7,
  ARM_S8,  ARM_S9, ARM_S10, ARM_S11,
  ARM_S12, ARM_S13, ARM_S14, ARM_S15,
  ARM_S16, ARM_S17, ARM_S18, ARM_S19,
  ARM_S20, ARM_S21, ARM_S22, ARM_S23,
  ARM_S24, ARM_S25, ARM_S26, ARM_S27,
  ARM_S28, ARM_S29, ARM_S30, ARM_S31
};

static DecodeStatus DecodeSPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  unsigned Register;

  if (RegNo > 31)
    return MCDisassembler_Fail;

  Register = SPRDecoderTable[RegNo];
  MCOperand_CreateReg0(Inst, Register);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeHPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  return DecodeSPRRegisterClass(Inst, RegNo, Address, Decoder);
}

static const uint16_t DPRDecoderTable[] = {
  ARM_D0,  ARM_D1,  ARM_D2,  ARM_D3,
  ARM_D4,  ARM_D5,  ARM_D6,  ARM_D7,
  ARM_D8,  ARM_D9, ARM_D10, ARM_D11,
  ARM_D12, ARM_D13, ARM_D14, ARM_D15,
  ARM_D16, ARM_D17, ARM_D18, ARM_D19,
  ARM_D20, ARM_D21, ARM_D22, ARM_D23,
  ARM_D24, ARM_D25, ARM_D26, ARM_D27,
  ARM_D28, ARM_D29, ARM_D30, ARM_D31
};

static DecodeStatus DecodeDPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  unsigned Register;

  if (RegNo > 31 || (ARM_getFeatureBits(Inst->csh->mode, ARM_FeatureD16) && RegNo > 15))
    return MCDisassembler_Fail;

  Register = DPRDecoderTable[RegNo];
  MCOperand_CreateReg0(Inst, Register);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeDPR_8RegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  if (RegNo > 7)
    return MCDisassembler_Fail;

  return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
}

static DecodeStatus DecodeDPR_VFP2RegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  if (RegNo > 15)
    return MCDisassembler_Fail;

  return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
}

static const uint16_t QPRDecoderTable[] = {
  ARM_Q0,  ARM_Q1,  ARM_Q2,  ARM_Q3,
  ARM_Q4,  ARM_Q5,  ARM_Q6,  ARM_Q7,
  ARM_Q8,  ARM_Q9, ARM_Q10, ARM_Q11,
  ARM_Q12, ARM_Q13, ARM_Q14, ARM_Q15
};

static DecodeStatus DecodeQPRRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  unsigned Register;

  if (RegNo > 31 || (RegNo & 1) != 0)
    return MCDisassembler_Fail;

  RegNo >>= 1;

  Register = QPRDecoderTable[RegNo];
  MCOperand_CreateReg0(Inst, Register);

  return MCDisassembler_Success;
}

static const uint16_t DPairDecoderTable[] = {
  ARM_Q0,  ARM_D1_D2,   ARM_Q1,  ARM_D3_D4,   ARM_Q2,  ARM_D5_D6,
  ARM_Q3,  ARM_D7_D8,   ARM_Q4,  ARM_D9_D10,  ARM_Q5,  ARM_D11_D12,
  ARM_Q6,  ARM_D13_D14, ARM_Q7,  ARM_D15_D16, ARM_Q8,  ARM_D17_D18,
  ARM_Q9,  ARM_D19_D20, ARM_Q10, ARM_D21_D22, ARM_Q11, ARM_D23_D24,
  ARM_Q12, ARM_D25_D26, ARM_Q13, ARM_D27_D28, ARM_Q14, ARM_D29_D30,
  ARM_Q15
};

static DecodeStatus DecodeDPairRegisterClass(MCInst *Inst, unsigned RegNo,
    uint64_t Address, const void *Decoder)
{
  unsigned Register;

  if (RegNo > 30)
    return MCDisassembler_Fail;

  Register = DPairDecoderTable[RegNo];
  MCOperand_CreateReg0(Inst, Register);

  return MCDisassembler_Success;
}

static const uint16_t DPairSpacedDecoderTable[] = {
  ARM_D0_D2,   ARM_D1_D3,   ARM_D2_D4,   ARM_D3_D5,
  ARM_D4_D6,   ARM_D5_D7,   ARM_D6_D8,   ARM_D7_D9,
  ARM_D8_D10,  ARM_D9_D11,  ARM_D10_D12, ARM_D11_D13,
  ARM_D12_D14, ARM_D13_D15, ARM_D14_D16, ARM_D15_D17,
  ARM_D16_D18, ARM_D17_D19, ARM_D18_D20, ARM_D19_D21,
  ARM_D20_D22, ARM_D21_D23, ARM_D22_D24, ARM_D23_D25,
  ARM_D24_D26, ARM_D25_D27, ARM_D26_D28, ARM_D27_D29,
  ARM_D28_D30, ARM_D29_D31
};

static DecodeStatus DecodeDPairSpacedRegisterClass(MCInst *Inst,
    unsigned RegNo, uint64_t Address, const void *Decoder)
{
  unsigned Register;

  if (RegNo > 29)
    return MCDisassembler_Fail;

  Register = DPairSpacedDecoderTable[RegNo];
  MCOperand_CreateReg0(Inst, Register);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeCCOutOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  if (Val)
    MCOperand_CreateReg0(Inst, ARM_CPSR);
  else
    MCOperand_CreateReg0(Inst, 0);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeSORegImmOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  ARM_AM_ShiftOpc Shift;
  unsigned Op;
  unsigned Rm = fieldFromInstruction_4(Val, 0, 4);
  unsigned type = fieldFromInstruction_4(Val, 5, 2);
  unsigned imm = fieldFromInstruction_4(Val, 7, 5);

  // Register-immediate
  if (!Check(&S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  Shift = ARM_AM_lsl;
  switch (type) {
    case 0:
      Shift = ARM_AM_lsl;
      break;
    case 1:
      Shift = ARM_AM_lsr;
      break;
    case 2:
      Shift = ARM_AM_asr;
      break;
    case 3:
      Shift = ARM_AM_ror;
      break;
  }

  if (Shift == ARM_AM_ror && imm == 0)
    Shift = ARM_AM_rrx;

  Op = Shift | (imm << 3);
  MCOperand_CreateImm0(Inst, Op);

  return S;
}

static DecodeStatus DecodeSORegRegOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  ARM_AM_ShiftOpc Shift;

  unsigned Rm = fieldFromInstruction_4(Val, 0, 4);
  unsigned type = fieldFromInstruction_4(Val, 5, 2);
  unsigned Rs = fieldFromInstruction_4(Val, 8, 4);

  // Register-register
  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;
  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)))
    return MCDisassembler_Fail;

  Shift = ARM_AM_lsl;
  switch (type) {
    case 0:
      Shift = ARM_AM_lsl;
      break;
    case 1:
      Shift = ARM_AM_lsr;
      break;
    case 2:
      Shift = ARM_AM_asr;
      break;
    case 3:
      Shift = ARM_AM_ror;
      break;
  }

  MCOperand_CreateImm0(Inst, Shift);

  return S;
}

static DecodeStatus DecodeRegListOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  unsigned i;
  DecodeStatus S = MCDisassembler_Success;
  unsigned opcode;
  bool NeedDisjointWriteback = false;
  unsigned WritebackReg = 0;

  opcode = MCInst_getOpcode(Inst);
  switch (opcode) {
    default:
      break;

    case ARM_LDMIA_UPD:
    case ARM_LDMDB_UPD:
    case ARM_LDMIB_UPD:
    case ARM_LDMDA_UPD:
    case ARM_t2LDMIA_UPD:
    case ARM_t2LDMDB_UPD:
    case ARM_t2STMIA_UPD:
    case ARM_t2STMDB_UPD:
      NeedDisjointWriteback = true;
      WritebackReg = MCOperand_getReg(MCInst_getOperand(Inst, 0));
      break;
  }

  // Empty register lists are not allowed.
  if (Val == 0) return MCDisassembler_Fail;

  for (i = 0; i < 16; ++i) {
    if (Val & (1 << i)) {
      if (!Check(&S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
        return MCDisassembler_Fail;

      // Writeback not allowed if Rn is in the target list.
      if (NeedDisjointWriteback && WritebackReg == MCOperand_getReg(&(Inst->Operands[Inst->size - 1])))
        Check(&S, MCDisassembler_SoftFail);
    }
  }

  return S;
}

static DecodeStatus DecodeSPRRegListOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned i;
  unsigned Vd = fieldFromInstruction_4(Val, 8, 5);
  unsigned regs = fieldFromInstruction_4(Val, 0, 8);

  // In case of unpredictable encoding, tweak the operands.
  if (regs == 0 || (Vd + regs) > 32) {
    regs = Vd + regs > 32 ? 32 - Vd : regs;
    regs = (1u > regs? 1u : regs);
    S = MCDisassembler_SoftFail;
  }

  if (!Check(&S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
    return MCDisassembler_Fail;

  for (i = 0; i < (regs - 1); ++i) {
    if (!Check(&S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  return S;
}

static DecodeStatus DecodeDPRRegListOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned i;
  unsigned Vd = fieldFromInstruction_4(Val, 8, 5);
  unsigned regs = fieldFromInstruction_4(Val, 1, 7);

  // In case of unpredictable encoding, tweak the operands.
  if (regs == 0 || regs > 16 || (Vd + regs) > 32) {
    regs = Vd + regs > 32 ? 32 - Vd : regs;
    regs = (1u > regs? 1u : regs);
    regs = (16u > regs? regs : 16u);
    S = MCDisassembler_SoftFail;
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
    return MCDisassembler_Fail;

  for (i = 0; i < (regs - 1); ++i) {
    if (!Check(&S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  return S;
}

static DecodeStatus DecodeBitfieldMaskOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  // This operand encodes a mask of contiguous zeros between a specified MSB
  // and LSB.  To decode it, we create the mask of all bits MSB-and-lower,
  // the mask of all bits LSB-and-lower, and then xor them to create
  // the mask of that's all ones on [msb, lsb].  Finally we not it to
  // create the final mask.
  unsigned msb = fieldFromInstruction_4(Val, 5, 5);
  unsigned lsb = fieldFromInstruction_4(Val, 0, 5);
  uint32_t lsb_mask, msb_mask;

  DecodeStatus S = MCDisassembler_Success;
  if (lsb > msb) {
    Check(&S, MCDisassembler_SoftFail);
    // The check above will cause the warning for the "potentially undefined
    // instruction encoding" but we can't build a bad MCOperand value here
    // with a lsb > msb or else printing the MCInst will cause a crash.
    lsb = msb;
  }

  msb_mask = 0xFFFFFFFF;
  if (msb != 31) msb_mask = (1U << (msb + 1)) - 1;
  lsb_mask = (1U << lsb) - 1;

  MCOperand_CreateImm0(Inst, ~(msb_mask ^ lsb_mask));
  return S;
}

static DecodeStatus DecodeCopMemInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);
  unsigned CRd = fieldFromInstruction_4(Insn, 12, 4);
  unsigned coproc = fieldFromInstruction_4(Insn, 8, 4);
  unsigned imm = fieldFromInstruction_4(Insn, 0, 8);
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned U = fieldFromInstruction_4(Insn, 23, 1);

  switch (MCInst_getOpcode(Inst)) {
    case ARM_LDC_OFFSET:
    case ARM_LDC_PRE:
    case ARM_LDC_POST:
    case ARM_LDC_OPTION:
    case ARM_LDCL_OFFSET:
    case ARM_LDCL_PRE:
    case ARM_LDCL_POST:
    case ARM_LDCL_OPTION:
    case ARM_STC_OFFSET:
    case ARM_STC_PRE:
    case ARM_STC_POST:
    case ARM_STC_OPTION:
    case ARM_STCL_OFFSET:
    case ARM_STCL_PRE:
    case ARM_STCL_POST:
    case ARM_STCL_OPTION:
    case ARM_t2LDC_OFFSET:
    case ARM_t2LDC_PRE:
    case ARM_t2LDC_POST:
    case ARM_t2LDC_OPTION:
    case ARM_t2LDCL_OFFSET:
    case ARM_t2LDCL_PRE:
    case ARM_t2LDCL_POST:
    case ARM_t2LDCL_OPTION:
    case ARM_t2STC_OFFSET:
    case ARM_t2STC_PRE:
    case ARM_t2STC_POST:
    case ARM_t2STC_OPTION:
    case ARM_t2STCL_OFFSET:
    case ARM_t2STCL_PRE:
    case ARM_t2STCL_POST:
    case ARM_t2STCL_OPTION:
      if (coproc == 0xA || coproc == 0xB)
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  if (ARM_getFeatureBits(Inst->csh->mode, ARM_HasV8Ops) && (coproc != 14))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, coproc);
  MCOperand_CreateImm0(Inst, CRd);
  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  switch (MCInst_getOpcode(Inst)) {
    case ARM_t2LDC2_OFFSET:
    case ARM_t2LDC2L_OFFSET:
    case ARM_t2LDC2_PRE:
    case ARM_t2LDC2L_PRE:
    case ARM_t2STC2_OFFSET:
    case ARM_t2STC2L_OFFSET:
    case ARM_t2STC2_PRE:
    case ARM_t2STC2L_PRE:
    case ARM_LDC2_OFFSET:
    case ARM_LDC2L_OFFSET:
    case ARM_LDC2_PRE:
    case ARM_LDC2L_PRE:
    case ARM_STC2_OFFSET:
    case ARM_STC2L_OFFSET:
    case ARM_STC2_PRE:
    case ARM_STC2L_PRE:
    case ARM_t2LDC_OFFSET:
    case ARM_t2LDCL_OFFSET:
    case ARM_t2LDC_PRE:
    case ARM_t2LDCL_PRE:
    case ARM_t2STC_OFFSET:
    case ARM_t2STCL_OFFSET:
    case ARM_t2STC_PRE:
    case ARM_t2STCL_PRE:
    case ARM_LDC_OFFSET:
    case ARM_LDCL_OFFSET:
    case ARM_LDC_PRE:
    case ARM_LDCL_PRE:
    case ARM_STC_OFFSET:
    case ARM_STCL_OFFSET:
    case ARM_STC_PRE:
    case ARM_STCL_PRE:
      imm = ARM_AM_getAM5Opc(U ? ARM_AM_add : ARM_AM_sub, (unsigned char)imm);
      MCOperand_CreateImm0(Inst, imm);
      break;
    case ARM_t2LDC2_POST:
    case ARM_t2LDC2L_POST:
    case ARM_t2STC2_POST:
    case ARM_t2STC2L_POST:
    case ARM_LDC2_POST:
    case ARM_LDC2L_POST:
    case ARM_STC2_POST:
    case ARM_STC2L_POST:
    case ARM_t2LDC_POST:
    case ARM_t2LDCL_POST:
    case ARM_t2STC_POST:
    case ARM_t2STCL_POST:
    case ARM_LDC_POST:
    case ARM_LDCL_POST:
    case ARM_STC_POST:
    case ARM_STCL_POST:
      imm |= U << 8;
      // fall through.
    default:
      // The 'option' variant doesn't encode 'U' in the immediate since
      // the immediate is unsigned [0,255].
      MCOperand_CreateImm0(Inst, imm);
      break;
  }

  switch (MCInst_getOpcode(Inst)) {
    case ARM_LDC_OFFSET:
    case ARM_LDC_PRE:
    case ARM_LDC_POST:
    case ARM_LDC_OPTION:
    case ARM_LDCL_OFFSET:
    case ARM_LDCL_PRE:
    case ARM_LDCL_POST:
    case ARM_LDCL_OPTION:
    case ARM_STC_OFFSET:
    case ARM_STC_PRE:
    case ARM_STC_POST:
    case ARM_STC_OPTION:
    case ARM_STCL_OFFSET:
    case ARM_STCL_PRE:
    case ARM_STCL_POST:
    case ARM_STCL_OPTION:
      if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  return S;
}

static DecodeStatus DecodeAddrMode2IdxInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  ARM_AM_AddrOpc Op;
  ARM_AM_ShiftOpc Opc;
  bool writeback;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned imm = fieldFromInstruction_4(Insn, 0, 12);
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);
  unsigned reg = fieldFromInstruction_4(Insn, 25, 1);
  unsigned P = fieldFromInstruction_4(Insn, 24, 1);
  unsigned W = fieldFromInstruction_4(Insn, 21, 1);
  unsigned idx_mode = 0, amt, tmp;

  // On stores, the writeback operand precedes Rt.
  switch (MCInst_getOpcode(Inst)) {
    case ARM_STR_POST_IMM:
    case ARM_STR_POST_REG:
    case ARM_STRB_POST_IMM:
    case ARM_STRB_POST_REG:
    case ARM_STRT_POST_REG:
    case ARM_STRT_POST_IMM:
    case ARM_STRBT_POST_REG:
    case ARM_STRBT_POST_IMM:
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  // On loads, the writeback operand comes after Rt.
  switch (MCInst_getOpcode(Inst)) {
    case ARM_LDR_POST_IMM:
    case ARM_LDR_POST_REG:
    case ARM_LDRB_POST_IMM:
    case ARM_LDRB_POST_REG:
    case ARM_LDRBT_POST_REG:
    case ARM_LDRBT_POST_IMM:
    case ARM_LDRT_POST_REG:
    case ARM_LDRT_POST_IMM:
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  Op = ARM_AM_add;
  if (!fieldFromInstruction_4(Insn, 23, 1))
    Op = ARM_AM_sub;

  writeback = (P == 0) || (W == 1);
  if (P && writeback)
    idx_mode = ARMII_IndexModePre;
  else if (!P && writeback)
    idx_mode = ARMII_IndexModePost;

  if (writeback && (Rn == 15 || Rn == Rt))
    S = MCDisassembler_SoftFail; // UNPREDICTABLE

  if (reg) {
    if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
      return MCDisassembler_Fail;

    Opc = ARM_AM_lsl;
    switch(fieldFromInstruction_4(Insn, 5, 2)) {
      case 0:
        Opc = ARM_AM_lsl;
        break;
      case 1:
        Opc = ARM_AM_lsr;
        break;
      case 2:
        Opc = ARM_AM_asr;
        break;
      case 3:
        Opc = ARM_AM_ror;
        break;
      default:
        return MCDisassembler_Fail;
    }

    amt = fieldFromInstruction_4(Insn, 7, 5);
    if (Opc == ARM_AM_ror && amt == 0)
      Opc = ARM_AM_rrx;

    imm = ARM_AM_getAM2Opc(Op, amt, Opc, idx_mode);

    MCOperand_CreateImm0(Inst, imm);
  } else {
    MCOperand_CreateReg0(Inst, 0);
    tmp = ARM_AM_getAM2Opc(Op, imm, ARM_AM_lsl, idx_mode);
    MCOperand_CreateImm0(Inst, tmp);
  }

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeSORegMemOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  ARM_AM_ShiftOpc ShOp;
  unsigned shift;
  unsigned Rn = fieldFromInstruction_4(Val, 13, 4);
  unsigned Rm = fieldFromInstruction_4(Val,  0, 4);
  unsigned type = fieldFromInstruction_4(Val, 5, 2);
  unsigned imm = fieldFromInstruction_4(Val, 7, 5);
  unsigned U = fieldFromInstruction_4(Val, 12, 1);

  ShOp = ARM_AM_lsl;
  switch (type) {
    case 0:
      ShOp = ARM_AM_lsl;
      break;
    case 1:
      ShOp = ARM_AM_lsr;
      break;
    case 2:
      ShOp = ARM_AM_asr;
      break;
    case 3:
      ShOp = ARM_AM_ror;
      break;
  }

  if (ShOp == ARM_AM_ror && imm == 0)
    ShOp = ARM_AM_rrx;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  if (U)
    shift = ARM_AM_getAM2Opc(ARM_AM_add, imm, ShOp, 0);
  else
    shift = ARM_AM_getAM2Opc(ARM_AM_sub, imm, ShOp, 0);

  MCOperand_CreateImm0(Inst, shift);

  return S;
}

static DecodeStatus DecodeAddrMode3Instruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned type = fieldFromInstruction_4(Insn, 22, 1);
  unsigned imm = fieldFromInstruction_4(Insn, 8, 4);
  unsigned U = ((~fieldFromInstruction_4(Insn, 23, 1)) & 1) << 8;
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);
  unsigned W = fieldFromInstruction_4(Insn, 21, 1);
  unsigned P = fieldFromInstruction_4(Insn, 24, 1);
  unsigned Rt2 = Rt + 1;

  bool writeback = (W == 1) | (P == 0);

  // For {LD,ST}RD, Rt must be even, else undefined.
  switch (MCInst_getOpcode(Inst)) {
    case ARM_STRD:
    case ARM_STRD_PRE:
    case ARM_STRD_POST:
    case ARM_LDRD:
    case ARM_LDRD_PRE:
    case ARM_LDRD_POST:
      if (Rt & 0x1)
        S = MCDisassembler_SoftFail;
      break;
    default:
      break;
  }

  switch (MCInst_getOpcode(Inst)) {
    case ARM_STRD:
    case ARM_STRD_PRE:
    case ARM_STRD_POST:
      if (P == 0 && W == 1)
        S = MCDisassembler_SoftFail;

      if (writeback && (Rn == 15 || Rn == Rt || Rn == Rt2))
        S = MCDisassembler_SoftFail;

      if (type && Rm == 15)
        S = MCDisassembler_SoftFail;

      if (Rt2 == 15)
        S = MCDisassembler_SoftFail;

      if (!type && fieldFromInstruction_4(Insn, 8, 4))
        S = MCDisassembler_SoftFail;

      break;

    case ARM_STRH:
    case ARM_STRH_PRE:
    case ARM_STRH_POST:
      if (Rt == 15)
        S = MCDisassembler_SoftFail;

      if (writeback && (Rn == 15 || Rn == Rt))
        S = MCDisassembler_SoftFail;

      if (!type && Rm == 15)
        S = MCDisassembler_SoftFail;

      break;

    case ARM_LDRD:
    case ARM_LDRD_PRE:
    case ARM_LDRD_POST:
      if (type && Rn == 15) {
        if (Rt2 == 15)
          S = MCDisassembler_SoftFail;
        break;
      }

      if (P == 0 && W == 1)
        S = MCDisassembler_SoftFail;

      if (!type && (Rt2 == 15 || Rm == 15 || Rm == Rt || Rm == Rt2))
        S = MCDisassembler_SoftFail;

      if (!type && writeback && Rn == 15)
        S = MCDisassembler_SoftFail;

      if (writeback && (Rn == Rt || Rn == Rt2))
        S = MCDisassembler_SoftFail;

      break;

    case ARM_LDRH:
    case ARM_LDRH_PRE:
    case ARM_LDRH_POST:
      if (type && Rn == 15) {
        if (Rt == 15)
          S = MCDisassembler_SoftFail;
        break;
      }

      if (Rt == 15)
        S = MCDisassembler_SoftFail;

      if (!type && Rm == 15)
        S = MCDisassembler_SoftFail;

      if (!type && writeback && (Rn == 15 || Rn == Rt))
        S = MCDisassembler_SoftFail;
      break;

    case ARM_LDRSH:
    case ARM_LDRSH_PRE:
    case ARM_LDRSH_POST:
    case ARM_LDRSB:
    case ARM_LDRSB_PRE:
    case ARM_LDRSB_POST:
      if (type && Rn == 15){
        if (Rt == 15)
          S = MCDisassembler_SoftFail;
        break;
      }

      if (type && (Rt == 15 || (writeback && Rn == Rt)))
        S = MCDisassembler_SoftFail;

      if (!type && (Rt == 15 || Rm == 15))
        S = MCDisassembler_SoftFail;

      if (!type && writeback && (Rn == 15 || Rn == Rt))
        S = MCDisassembler_SoftFail;

      break;

    default:
      break;
  }

  if (writeback) { // Writeback
    Inst->writeback = true;

    if (P)
      U |= ARMII_IndexModePre << 9;
    else
      U |= ARMII_IndexModePost << 9;

    // On stores, the writeback operand precedes Rt.
    switch (MCInst_getOpcode(Inst)) {
      case ARM_STRD:
      case ARM_STRD_PRE:
      case ARM_STRD_POST:
      case ARM_STRH:
      case ARM_STRH_PRE:
      case ARM_STRH_POST:
        if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
          return MCDisassembler_Fail;
        break;
      default:
        break;
    }
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  switch (MCInst_getOpcode(Inst)) {
    case ARM_STRD:
    case ARM_STRD_PRE:
    case ARM_STRD_POST:
    case ARM_LDRD:
    case ARM_LDRD_PRE:
    case ARM_LDRD_POST:
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt + 1, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  if (writeback) {
    // On loads, the writeback operand comes after Rt.
    switch (MCInst_getOpcode(Inst)) {
      case ARM_LDRD:
      case ARM_LDRD_PRE:
      case ARM_LDRD_POST:
      case ARM_LDRH:
      case ARM_LDRH_PRE:
      case ARM_LDRH_POST:
      case ARM_LDRSH:
      case ARM_LDRSH_PRE:
      case ARM_LDRSH_POST:
      case ARM_LDRSB:
      case ARM_LDRSB_PRE:
      case ARM_LDRSB_POST:
      case ARM_LDRHTr:
      case ARM_LDRSBTr:
        if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
          return MCDisassembler_Fail;
        break;
      default:
        break;
    }
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (type) {
    MCOperand_CreateReg0(Inst, 0);
    MCOperand_CreateImm0(Inst, U | (imm << 4) | Rm);
  } else {
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
      return MCDisassembler_Fail;

    MCOperand_CreateImm0(Inst, U);
  }

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeRFEInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned mode = fieldFromInstruction_4(Insn, 23, 2);

  switch (mode) {
    case 0:
      mode = ARM_AM_da;
      break;
    case 1:
      mode = ARM_AM_ia;
      break;
    case 2:
      mode = ARM_AM_db;
      break;
    case 3:
      mode = ARM_AM_ib;
      break;
  }

  MCOperand_CreateImm0(Inst, mode);

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeQADDInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);

  if (pred == 0xF)
    return DecodeCPSInstruction(Inst, Insn, Address, Decoder);

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst *Inst,
    unsigned Insn, uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);
  unsigned reglist = fieldFromInstruction_4(Insn, 0, 16);

  if (pred == 0xF) {
    // Ambiguous with RFE and SRS
    switch (MCInst_getOpcode(Inst)) {
      case ARM_LDMDA:
        MCInst_setOpcode(Inst, ARM_RFEDA);
        break;
      case ARM_LDMDA_UPD:
        MCInst_setOpcode(Inst, ARM_RFEDA_UPD);
        break;
      case ARM_LDMDB:
        MCInst_setOpcode(Inst, ARM_RFEDB);
        break;
      case ARM_LDMDB_UPD:
        MCInst_setOpcode(Inst, ARM_RFEDB_UPD);
        break;
      case ARM_LDMIA:
        MCInst_setOpcode(Inst, ARM_RFEIA);
        break;
      case ARM_LDMIA_UPD:
        MCInst_setOpcode(Inst, ARM_RFEIA_UPD);
        break;
      case ARM_LDMIB:
        MCInst_setOpcode(Inst, ARM_RFEIB);
        break;
      case ARM_LDMIB_UPD:
        MCInst_setOpcode(Inst, ARM_RFEIB_UPD);
        break;
      case ARM_STMDA:
        MCInst_setOpcode(Inst, ARM_SRSDA);
        break;
      case ARM_STMDA_UPD:
        MCInst_setOpcode(Inst, ARM_SRSDA_UPD);
        break;
      case ARM_STMDB:
        MCInst_setOpcode(Inst, ARM_SRSDB);
        break;
      case ARM_STMDB_UPD:
        MCInst_setOpcode(Inst, ARM_SRSDB_UPD);
        break;
      case ARM_STMIA:
        MCInst_setOpcode(Inst, ARM_SRSIA);
        break;
      case ARM_STMIA_UPD:
        MCInst_setOpcode(Inst, ARM_SRSIA_UPD);
        break;
      case ARM_STMIB:
        MCInst_setOpcode(Inst, ARM_SRSIB);
        break;
      case ARM_STMIB_UPD:
        MCInst_setOpcode(Inst, ARM_SRSIB_UPD);
        break;
      default:
        return MCDisassembler_Fail;
    }

    // For stores (which become SRS's, the only operand is the mode.
    if (fieldFromInstruction_4(Insn, 20, 1) == 0) {
      // Check SRS encoding constraints
      if (!(fieldFromInstruction_4(Insn, 22, 1) == 1 &&
            fieldFromInstruction_4(Insn, 20, 1) == 0))
        return MCDisassembler_Fail;

      MCOperand_CreateImm0(Inst, fieldFromInstruction_4(Insn, 0, 4));
      return S;
    }

    return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail; // Tied

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeRegListOperand(Inst, reglist, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

// Check for UNPREDICTABLE predicated ESB instruction
static DecodeStatus DecodeHINTInstruction(MCInst *Inst, unsigned Insn,
                                 uint64_t Address, const void *Decoder)
{
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);
  unsigned imm8 = fieldFromInstruction_4(Insn, 0, 8);
  DecodeStatus result = MCDisassembler_Success;

  MCOperand_CreateImm0(Inst, imm8);

  if (!Check(&result, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  // ESB is unpredictable if pred != AL. Without the RAS extension, it is a NOP,
  // so all predicates should be allowed.
  if (imm8 == 0x10 && pred != 0xe && ARM_getFeatureBits(Inst->csh->mode, ARM_FeatureRAS))
    result = MCDisassembler_SoftFail;

  return result;
}

static DecodeStatus DecodeCPSInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  unsigned imod = fieldFromInstruction_4(Insn, 18, 2);
  unsigned M = fieldFromInstruction_4(Insn, 17, 1);
  unsigned iflags = fieldFromInstruction_4(Insn, 6, 3);
  unsigned mode = fieldFromInstruction_4(Insn, 0, 5);

  DecodeStatus S = MCDisassembler_Success;

  // This decoder is called from multiple location that do not check
  // the full encoding is valid before they do.
  if (fieldFromInstruction_4(Insn, 5, 1) != 0 ||
      fieldFromInstruction_4(Insn, 16, 1) != 0 ||
      fieldFromInstruction_4(Insn, 20, 8) != 0x10)
    return MCDisassembler_Fail;

  // imod == '01' --> UNPREDICTABLE
  // NOTE: Even though this is technically UNPREDICTABLE, we choose to
  // return failure here.  The '01' imod value is unprintable, so there's
  // nothing useful we could do even if we returned UNPREDICTABLE.

  if (imod == 1) return MCDisassembler_Fail;

  if (imod && M) {
    MCInst_setOpcode(Inst, ARM_CPS3p);
    MCOperand_CreateImm0(Inst, imod);
    MCOperand_CreateImm0(Inst, iflags);
    MCOperand_CreateImm0(Inst, mode);
  } else if (imod && !M) {
    MCInst_setOpcode(Inst, ARM_CPS2p);
    MCOperand_CreateImm0(Inst, imod);
    MCOperand_CreateImm0(Inst, iflags);
    if (mode) S = MCDisassembler_SoftFail;
  } else if (!imod && M) {
    MCInst_setOpcode(Inst, ARM_CPS1p);
    MCOperand_CreateImm0(Inst, mode);
    if (iflags) S = MCDisassembler_SoftFail;
  } else {
    // imod == '00' && M == '0' --> UNPREDICTABLE
    MCInst_setOpcode(Inst, ARM_CPS1p);
    MCOperand_CreateImm0(Inst, mode);
    S = MCDisassembler_SoftFail;
  }

  return S;
}

static DecodeStatus DecodeT2CPSInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  unsigned imod = fieldFromInstruction_4(Insn, 9, 2);
  unsigned M = fieldFromInstruction_4(Insn, 8, 1);
  unsigned iflags = fieldFromInstruction_4(Insn, 5, 3);
  unsigned mode = fieldFromInstruction_4(Insn, 0, 5);

  DecodeStatus S = MCDisassembler_Success;

  // imod == '01' --> UNPREDICTABLE
  // NOTE: Even though this is technically UNPREDICTABLE, we choose to
  // return failure here.  The '01' imod value is unprintable, so there's
  // nothing useful we could do even if we returned UNPREDICTABLE.

  if (imod == 1) return MCDisassembler_Fail;

  if (imod && M) {
    MCInst_setOpcode(Inst, ARM_t2CPS3p);
    MCOperand_CreateImm0(Inst, imod);
    MCOperand_CreateImm0(Inst, iflags);
    MCOperand_CreateImm0(Inst, mode);
  } else if (imod && !M) {
    MCInst_setOpcode(Inst, ARM_t2CPS2p);
    MCOperand_CreateImm0(Inst, imod);
    MCOperand_CreateImm0(Inst, iflags);
    if (mode) S = MCDisassembler_SoftFail;
  } else if (!imod && M) {
    MCInst_setOpcode(Inst, ARM_t2CPS1p);
    MCOperand_CreateImm0(Inst, mode);
    if (iflags) S = MCDisassembler_SoftFail;
  } else {
    // imod == '00' && M == '0' --> this is a HINT instruction
    int imm = fieldFromInstruction_4(Insn, 0, 8);
    // HINT are defined only for immediate in [0..4]
    if (imm > 4) return MCDisassembler_Fail;

    MCInst_setOpcode(Inst, ARM_t2HINT);
    MCOperand_CreateImm0(Inst, imm);
  }

  return S;
}

static DecodeStatus DecodeT2MOVTWInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned Rd = fieldFromInstruction_4(Insn, 8, 4);
  unsigned imm = 0;

  imm |= (fieldFromInstruction_4(Insn, 0, 8) << 0);
  imm |= (fieldFromInstruction_4(Insn, 12, 3) << 8);
  imm |= (fieldFromInstruction_4(Insn, 16, 4) << 12);
  imm |= (fieldFromInstruction_4(Insn, 26, 1) << 11);

  if (MCInst_getOpcode(Inst) == ARM_t2MOVTi16)
    if (!Check(&S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
      return MCDisassembler_Fail;

  if (!Check(&S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, imm);

  return S;
}

static DecodeStatus DecodeArmMOVTWInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);
  unsigned imm = 0;

  imm |= (fieldFromInstruction_4(Insn, 0, 12) << 0);
  imm |= (fieldFromInstruction_4(Insn, 16, 4) << 12);

  if (MCInst_getOpcode(Inst) == ARM_MOVTi16)
    if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
      return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, imm);

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeSMLAInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned Rd = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rn = fieldFromInstruction_4(Insn, 0, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 8, 4);
  unsigned Ra = fieldFromInstruction_4(Insn, 12, 4);
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);

  if (pred == 0xF)
    return DecodeCPSInstruction(Inst, Insn, Address, Decoder);

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeTSTInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Pred = fieldFromInstruction_4(Insn, 28, 4);
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);

  if (Pred == 0xF)
    return DecodeSETPANInstruction(Inst, Insn, Address, Decoder);

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, Pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeSETPANInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Imm = fieldFromInstruction_4(Insn, 9, 1);

  if (!ARM_getFeatureBits(Inst->csh->mode, ARM_HasV8_1aOps) || !ARM_getFeatureBits(Inst->csh->mode, ARM_HasV8Ops))
    return MCDisassembler_Fail;

  // Decoder can be called from DecodeTST, which does not check the full
  // encoding is valid.
  if (fieldFromInstruction_4(Insn, 20, 12) != 0xf11 ||
      fieldFromInstruction_4(Insn, 4, 4) != 0)
    return MCDisassembler_Fail;

  if (fieldFromInstruction_4(Insn, 10, 10) != 0 ||
      fieldFromInstruction_4(Insn, 0, 4) != 0)
    S = MCDisassembler_SoftFail;

  MCInst_setOpcode(Inst, ARM_SETPAN);
  MCOperand_CreateImm0(Inst, Imm);

  return S;
}

static DecodeStatus DecodeAddrModeImm12Operand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned add = fieldFromInstruction_4(Val, 12, 1);
  unsigned imm = fieldFromInstruction_4(Val, 0, 12);
  unsigned Rn = fieldFromInstruction_4(Val, 13, 4);

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!add) imm *= (unsigned int)-1;
  if (imm == 0 && !add) imm = (unsigned int)INT32_MIN;

  MCOperand_CreateImm0(Inst, imm);
  //if (Rn == 15)
  //  tryAddingPcLoadReferenceComment(Address, Address + imm + 8, Decoder);

  return S;
}

static DecodeStatus DecodeAddrMode5Operand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn = fieldFromInstruction_4(Val, 9, 4);
  // U == 1 to add imm, 0 to subtract it.
  unsigned U = fieldFromInstruction_4(Val, 8, 1);
  unsigned imm = fieldFromInstruction_4(Val, 0, 8);

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (U)
    MCOperand_CreateImm0(Inst, ARM_AM_getAM5Opc(ARM_AM_add, (unsigned char)imm));
  else
    MCOperand_CreateImm0(Inst, ARM_AM_getAM5Opc(ARM_AM_sub, (unsigned char)imm));

  return S;
}

static DecodeStatus DecodeAddrMode5FP16Operand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn = fieldFromInstruction_4(Val, 9, 4);
  // U == 1 to add imm, 0 to subtract it.
  unsigned U = fieldFromInstruction_4(Val, 8, 1);
  unsigned imm = fieldFromInstruction_4(Val, 0, 8);

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (U)
    MCOperand_CreateImm0(Inst, getAM5FP16Opc(ARM_AM_add, imm));
  else
    MCOperand_CreateImm0(Inst, getAM5FP16Opc(ARM_AM_sub, imm));

  return S;
}

static DecodeStatus DecodeAddrMode7Operand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
}

static DecodeStatus DecodeT2BInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus Status = MCDisassembler_Success;

  // Note the J1 and J2 values are from the encoded instruction.  So here
  // change them to I1 and I2 values via as documented:
  // I1 = NOT(J1 EOR S);
  // I2 = NOT(J2 EOR S);
  // and build the imm32 with one trailing zero as documented:
  // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
  unsigned S = fieldFromInstruction_4(Insn, 26, 1);
  unsigned J1 = fieldFromInstruction_4(Insn, 13, 1);
  unsigned J2 = fieldFromInstruction_4(Insn, 11, 1);
  unsigned I1 = !(J1 ^ S);
  unsigned I2 = !(J2 ^ S);
  unsigned imm10 = fieldFromInstruction_4(Insn, 16, 10);
  unsigned imm11 = fieldFromInstruction_4(Insn, 0, 11);
  unsigned tmp = (S << 23) | (I1 << 22) | (I2 << 21) | (imm10 << 11) | imm11;
  int imm32 = SignExtend32(tmp << 1, 25);

  MCOperand_CreateImm0(Inst, imm32);

  return Status;
}

static DecodeStatus DecodeBranchImmInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);
  unsigned imm = fieldFromInstruction_4(Insn, 0, 24) << 2;

  if (pred == 0xF) {
    MCInst_setOpcode(Inst, ARM_BLXi);
    imm |= fieldFromInstruction_4(Insn, 24, 1) << 1;
    MCOperand_CreateImm0(Inst, SignExtend32(imm, 26));
    return S;
  }

  MCOperand_CreateImm0(Inst, SignExtend32(imm, 26));

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}


static DecodeStatus DecodeAddrMode6Operand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned Rm = fieldFromInstruction_4(Val, 0, 4);
  unsigned align = fieldFromInstruction_4(Val, 4, 2);

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!align)
    MCOperand_CreateImm0(Inst, 0);
  else
    MCOperand_CreateImm0(Inst, 4 << align);

  return S;
}

static DecodeStatus DecodeVLDInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned wb, Rn, Rm;
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  wb = fieldFromInstruction_4(Insn, 16, 4);
  Rn = fieldFromInstruction_4(Insn, 16, 4);
  Rn |= fieldFromInstruction_4(Insn, 4, 2) << 4;
  Rm = fieldFromInstruction_4(Insn, 0, 4);

  // First output register
  switch (MCInst_getOpcode(Inst)) {
    case ARM_VLD1q16: case ARM_VLD1q32: case ARM_VLD1q64: case ARM_VLD1q8:
    case ARM_VLD1q16wb_fixed: case ARM_VLD1q16wb_register:
    case ARM_VLD1q32wb_fixed: case ARM_VLD1q32wb_register:
    case ARM_VLD1q64wb_fixed: case ARM_VLD1q64wb_register:
    case ARM_VLD1q8wb_fixed: case ARM_VLD1q8wb_register:
    case ARM_VLD2d16: case ARM_VLD2d32: case ARM_VLD2d8:
    case ARM_VLD2d16wb_fixed: case ARM_VLD2d16wb_register:
    case ARM_VLD2d32wb_fixed: case ARM_VLD2d32wb_register:
    case ARM_VLD2d8wb_fixed: case ARM_VLD2d8wb_register:
      if (!Check(&S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    case ARM_VLD2b16:
    case ARM_VLD2b32:
    case ARM_VLD2b8:
    case ARM_VLD2b16wb_fixed:
    case ARM_VLD2b16wb_register:
    case ARM_VLD2b32wb_fixed:
    case ARM_VLD2b32wb_register:
    case ARM_VLD2b8wb_fixed:
    case ARM_VLD2b8wb_register:
      if (!Check(&S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    default:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
  }

  // Second output register
  switch (MCInst_getOpcode(Inst)) {
    case ARM_VLD3d8:
    case ARM_VLD3d16:
    case ARM_VLD3d32:
    case ARM_VLD3d8_UPD:
    case ARM_VLD3d16_UPD:
    case ARM_VLD3d32_UPD:
    case ARM_VLD4d8:
    case ARM_VLD4d16:
    case ARM_VLD4d32:
    case ARM_VLD4d8_UPD:
    case ARM_VLD4d16_UPD:
    case ARM_VLD4d32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 1) % 32, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    case ARM_VLD3q8:
    case ARM_VLD3q16:
    case ARM_VLD3q32:
    case ARM_VLD3q8_UPD:
    case ARM_VLD3q16_UPD:
    case ARM_VLD3q32_UPD:
    case ARM_VLD4q8:
    case ARM_VLD4q16:
    case ARM_VLD4q32:
    case ARM_VLD4q8_UPD:
    case ARM_VLD4q16_UPD:
    case ARM_VLD4q32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 2) % 32, Address, Decoder)))
        return MCDisassembler_Fail;

    default:
      break;
  }

  // Third output register
  switch(MCInst_getOpcode(Inst)) {
    case ARM_VLD3d8:
    case ARM_VLD3d16:
    case ARM_VLD3d32:
    case ARM_VLD3d8_UPD:
    case ARM_VLD3d16_UPD:
    case ARM_VLD3d32_UPD:
    case ARM_VLD4d8:
    case ARM_VLD4d16:
    case ARM_VLD4d32:
    case ARM_VLD4d8_UPD:
    case ARM_VLD4d16_UPD:
    case ARM_VLD4d32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 2) % 32, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    case ARM_VLD3q8:
    case ARM_VLD3q16:
    case ARM_VLD3q32:
    case ARM_VLD3q8_UPD:
    case ARM_VLD3q16_UPD:
    case ARM_VLD3q32_UPD:
    case ARM_VLD4q8:
    case ARM_VLD4q16:
    case ARM_VLD4q32:
    case ARM_VLD4q8_UPD:
    case ARM_VLD4q16_UPD:
    case ARM_VLD4q32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 4) % 32, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  // Fourth output register
  switch (MCInst_getOpcode(Inst)) {
    case ARM_VLD4d8:
    case ARM_VLD4d16:
    case ARM_VLD4d32:
    case ARM_VLD4d8_UPD:
    case ARM_VLD4d16_UPD:
    case ARM_VLD4d32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 3) % 32, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    case ARM_VLD4q8:
    case ARM_VLD4q16:
    case ARM_VLD4q32:
    case ARM_VLD4q8_UPD:
    case ARM_VLD4q16_UPD:
    case ARM_VLD4q32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 6) % 32, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  // Writeback operand
  switch (MCInst_getOpcode(Inst)) {
    case ARM_VLD1d8wb_fixed:
    case ARM_VLD1d16wb_fixed:
    case ARM_VLD1d32wb_fixed:
    case ARM_VLD1d64wb_fixed:
    case ARM_VLD1d8wb_register:
    case ARM_VLD1d16wb_register:
    case ARM_VLD1d32wb_register:
    case ARM_VLD1d64wb_register:
    case ARM_VLD1q8wb_fixed:
    case ARM_VLD1q16wb_fixed:
    case ARM_VLD1q32wb_fixed:
    case ARM_VLD1q64wb_fixed:
    case ARM_VLD1q8wb_register:
    case ARM_VLD1q16wb_register:
    case ARM_VLD1q32wb_register:
    case ARM_VLD1q64wb_register:
    case ARM_VLD1d8Twb_fixed:
    case ARM_VLD1d8Twb_register:
    case ARM_VLD1d16Twb_fixed:
    case ARM_VLD1d16Twb_register:
    case ARM_VLD1d32Twb_fixed:
    case ARM_VLD1d32Twb_register:
    case ARM_VLD1d64Twb_fixed:
    case ARM_VLD1d64Twb_register:
    case ARM_VLD1d8Qwb_fixed:
    case ARM_VLD1d8Qwb_register:
    case ARM_VLD1d16Qwb_fixed:
    case ARM_VLD1d16Qwb_register:
    case ARM_VLD1d32Qwb_fixed:
    case ARM_VLD1d32Qwb_register:
    case ARM_VLD1d64Qwb_fixed:
    case ARM_VLD1d64Qwb_register:
    case ARM_VLD2d8wb_fixed:
    case ARM_VLD2d16wb_fixed:
    case ARM_VLD2d32wb_fixed:
    case ARM_VLD2q8wb_fixed:
    case ARM_VLD2q16wb_fixed:
    case ARM_VLD2q32wb_fixed:
    case ARM_VLD2d8wb_register:
    case ARM_VLD2d16wb_register:
    case ARM_VLD2d32wb_register:
    case ARM_VLD2q8wb_register:
    case ARM_VLD2q16wb_register:
    case ARM_VLD2q32wb_register:
    case ARM_VLD2b8wb_fixed:
    case ARM_VLD2b16wb_fixed:
    case ARM_VLD2b32wb_fixed:
    case ARM_VLD2b8wb_register:
    case ARM_VLD2b16wb_register:
    case ARM_VLD2b32wb_register:
      MCOperand_CreateImm0(Inst, 0);
      break;

    case ARM_VLD3d8_UPD:
    case ARM_VLD3d16_UPD:
    case ARM_VLD3d32_UPD:
    case ARM_VLD3q8_UPD:
    case ARM_VLD3q16_UPD:
    case ARM_VLD3q32_UPD:
    case ARM_VLD4d8_UPD:
    case ARM_VLD4d16_UPD:
    case ARM_VLD4d32_UPD:
    case ARM_VLD4q8_UPD:
    case ARM_VLD4q16_UPD:
    case ARM_VLD4q32_UPD:
      if (!Check(&S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    default:
      break;
  }

  // AddrMode6 Base (register+alignment)
  if (!Check(&S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  // AddrMode6 Offset (register)
  switch (MCInst_getOpcode(Inst)) {
    default:
      // The below have been updated to have explicit am6offset split
      // between fixed and register offset. For those instructions not
      // yet updated, we need to add an additional reg0 operand for the
      // fixed variant.
      //
      // The fixed offset encodes as Rm == 0xd, so we check for that.
      if (Rm == 0xd) {
        MCOperand_CreateReg0(Inst, 0);
        break;
      }
      // Fall through to handle the register offset variant.

    case ARM_VLD1d8wb_fixed:
    case ARM_VLD1d16wb_fixed:
    case ARM_VLD1d32wb_fixed:
    case ARM_VLD1d64wb_fixed:
    case ARM_VLD1d8Twb_fixed:
    case ARM_VLD1d16Twb_fixed:
    case ARM_VLD1d32Twb_fixed:
    case ARM_VLD1d64Twb_fixed:
    case ARM_VLD1d8Qwb_fixed:
    case ARM_VLD1d16Qwb_fixed:
    case ARM_VLD1d32Qwb_fixed:
    case ARM_VLD1d64Qwb_fixed:
    case ARM_VLD1d8wb_register:
    case ARM_VLD1d16wb_register:
    case ARM_VLD1d32wb_register:
    case ARM_VLD1d64wb_register:
    case ARM_VLD1q8wb_fixed:
    case ARM_VLD1q16wb_fixed:
    case ARM_VLD1q32wb_fixed:
    case ARM_VLD1q64wb_fixed:
    case ARM_VLD1q8wb_register:
    case ARM_VLD1q16wb_register:
    case ARM_VLD1q32wb_register:
    case ARM_VLD1q64wb_register:
      // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
      // variant encodes Rm == 0xf. Anything else is a register offset post-
      // increment and we need to add the register operand to the instruction.
      if (Rm != 0xD && Rm != 0xF &&
          !Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    case ARM_VLD2d8wb_fixed:
    case ARM_VLD2d16wb_fixed:
    case ARM_VLD2d32wb_fixed:
    case ARM_VLD2b8wb_fixed:
    case ARM_VLD2b16wb_fixed:
    case ARM_VLD2b32wb_fixed:
    case ARM_VLD2q8wb_fixed:
    case ARM_VLD2q16wb_fixed:
    case ARM_VLD2q32wb_fixed:
      break;
  }

  return S;
}

static DecodeStatus DecodeVLDST1Instruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  unsigned load;
  unsigned type = fieldFromInstruction_4(Insn, 8, 4);
  unsigned align = fieldFromInstruction_4(Insn, 4, 2);
  if (type == 6 && (align & 2)) return MCDisassembler_Fail;
  if (type == 7 && (align & 2)) return MCDisassembler_Fail;
  if (type == 10 && align == 3) return MCDisassembler_Fail;

  load = fieldFromInstruction_4(Insn, 21, 1);

  return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
    : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
}

static DecodeStatus DecodeVLDST2Instruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  unsigned type, align, load;
  unsigned size = fieldFromInstruction_4(Insn, 6, 2);
  if (size == 3) return MCDisassembler_Fail;

  type = fieldFromInstruction_4(Insn, 8, 4);
  align = fieldFromInstruction_4(Insn, 4, 2);
  if (type == 8 && align == 3) return MCDisassembler_Fail;
  if (type == 9 && align == 3) return MCDisassembler_Fail;

  load = fieldFromInstruction_4(Insn, 21, 1);

  return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
    : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
}

static DecodeStatus DecodeVLDST3Instruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  unsigned align, load;
  unsigned size = fieldFromInstruction_4(Insn, 6, 2);
  if (size == 3) return MCDisassembler_Fail;

  align = fieldFromInstruction_4(Insn, 4, 2);
  if (align & 2) return MCDisassembler_Fail;

  load = fieldFromInstruction_4(Insn, 21, 1);

  return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
    : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
}

static DecodeStatus DecodeVLDST4Instruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  unsigned load;
  unsigned size = fieldFromInstruction_4(Insn, 6, 2);
  if (size == 3) return MCDisassembler_Fail;

  load = fieldFromInstruction_4(Insn, 21, 1);

  return load ? DecodeVLDInstruction(Inst, Insn, Address, Decoder)
    : DecodeVSTInstruction(Inst, Insn, Address, Decoder);
}

static DecodeStatus DecodeVSTInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned wb, Rn, Rm;
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  wb = fieldFromInstruction_4(Insn, 16, 4);
  Rn = fieldFromInstruction_4(Insn, 16, 4);
  Rn |= fieldFromInstruction_4(Insn, 4, 2) << 4;
  Rm = fieldFromInstruction_4(Insn, 0, 4);

  // Writeback Operand
  switch (MCInst_getOpcode(Inst)) {
    case ARM_VST1d8wb_fixed:
    case ARM_VST1d16wb_fixed:
    case ARM_VST1d32wb_fixed:
    case ARM_VST1d64wb_fixed:
    case ARM_VST1d8wb_register:
    case ARM_VST1d16wb_register:
    case ARM_VST1d32wb_register:
    case ARM_VST1d64wb_register:
    case ARM_VST1q8wb_fixed:
    case ARM_VST1q16wb_fixed:
    case ARM_VST1q32wb_fixed:
    case ARM_VST1q64wb_fixed:
    case ARM_VST1q8wb_register:
    case ARM_VST1q16wb_register:
    case ARM_VST1q32wb_register:
    case ARM_VST1q64wb_register:
    case ARM_VST1d8Twb_fixed:
    case ARM_VST1d16Twb_fixed:
    case ARM_VST1d32Twb_fixed:
    case ARM_VST1d64Twb_fixed:
    case ARM_VST1d8Twb_register:
    case ARM_VST1d16Twb_register:
    case ARM_VST1d32Twb_register:
    case ARM_VST1d64Twb_register:
    case ARM_VST1d8Qwb_fixed:
    case ARM_VST1d16Qwb_fixed:
    case ARM_VST1d32Qwb_fixed:
    case ARM_VST1d64Qwb_fixed:
    case ARM_VST1d8Qwb_register:
    case ARM_VST1d16Qwb_register:
    case ARM_VST1d32Qwb_register:
    case ARM_VST1d64Qwb_register:
    case ARM_VST2d8wb_fixed:
    case ARM_VST2d16wb_fixed:
    case ARM_VST2d32wb_fixed:
    case ARM_VST2d8wb_register:
    case ARM_VST2d16wb_register:
    case ARM_VST2d32wb_register:
    case ARM_VST2q8wb_fixed:
    case ARM_VST2q16wb_fixed:
    case ARM_VST2q32wb_fixed:
    case ARM_VST2q8wb_register:
    case ARM_VST2q16wb_register:
    case ARM_VST2q32wb_register:
    case ARM_VST2b8wb_fixed:
    case ARM_VST2b16wb_fixed:
    case ARM_VST2b32wb_fixed:
    case ARM_VST2b8wb_register:
    case ARM_VST2b16wb_register:
    case ARM_VST2b32wb_register:
      if (Rm == 0xF)
        return MCDisassembler_Fail;
      MCOperand_CreateImm0(Inst, 0);
      break;
    case ARM_VST3d8_UPD:
    case ARM_VST3d16_UPD:
    case ARM_VST3d32_UPD:
    case ARM_VST3q8_UPD:
    case ARM_VST3q16_UPD:
    case ARM_VST3q32_UPD:
    case ARM_VST4d8_UPD:
    case ARM_VST4d16_UPD:
    case ARM_VST4d32_UPD:
    case ARM_VST4q8_UPD:
    case ARM_VST4q16_UPD:
    case ARM_VST4q32_UPD:
      if (!Check(&S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  // AddrMode6 Base (register+alignment)
  if (!Check(&S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  // AddrMode6 Offset (register)
  switch (MCInst_getOpcode(Inst)) {
    default:
      if (Rm == 0xD)
        MCOperand_CreateReg0(Inst, 0);
      else if (Rm != 0xF) {
        if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
          return MCDisassembler_Fail;
      }
      break;

    case ARM_VST1d8wb_fixed:
    case ARM_VST1d16wb_fixed:
    case ARM_VST1d32wb_fixed:
    case ARM_VST1d64wb_fixed:
    case ARM_VST1q8wb_fixed:
    case ARM_VST1q16wb_fixed:
    case ARM_VST1q32wb_fixed:
    case ARM_VST1q64wb_fixed:
    case ARM_VST1d8Twb_fixed:
    case ARM_VST1d16Twb_fixed:
    case ARM_VST1d32Twb_fixed:
    case ARM_VST1d64Twb_fixed:
    case ARM_VST1d8Qwb_fixed:
    case ARM_VST1d16Qwb_fixed:
    case ARM_VST1d32Qwb_fixed:
    case ARM_VST1d64Qwb_fixed:
    case ARM_VST2d8wb_fixed:
    case ARM_VST2d16wb_fixed:
    case ARM_VST2d32wb_fixed:
    case ARM_VST2q8wb_fixed:
    case ARM_VST2q16wb_fixed:
    case ARM_VST2q32wb_fixed:
    case ARM_VST2b8wb_fixed:
    case ARM_VST2b16wb_fixed:
    case ARM_VST2b32wb_fixed:
      break;
  }


  // First input register
  switch (MCInst_getOpcode(Inst)) {
    case ARM_VST1q16:
    case ARM_VST1q32:
    case ARM_VST1q64:
    case ARM_VST1q8:
    case ARM_VST1q16wb_fixed:
    case ARM_VST1q16wb_register:
    case ARM_VST1q32wb_fixed:
    case ARM_VST1q32wb_register:
    case ARM_VST1q64wb_fixed:
    case ARM_VST1q64wb_register:
    case ARM_VST1q8wb_fixed:
    case ARM_VST1q8wb_register:
    case ARM_VST2d16:
    case ARM_VST2d32:
    case ARM_VST2d8:
    case ARM_VST2d16wb_fixed:
    case ARM_VST2d16wb_register:
    case ARM_VST2d32wb_fixed:
    case ARM_VST2d32wb_register:
    case ARM_VST2d8wb_fixed:
    case ARM_VST2d8wb_register:
      if (!Check(&S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    case ARM_VST2b16:
    case ARM_VST2b32:
    case ARM_VST2b8:
    case ARM_VST2b16wb_fixed:
    case ARM_VST2b16wb_register:
    case ARM_VST2b32wb_fixed:
    case ARM_VST2b32wb_register:
    case ARM_VST2b8wb_fixed:
    case ARM_VST2b8wb_register:
      if (!Check(&S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    default:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
  }

  // Second input register
  switch (MCInst_getOpcode(Inst)) {
    case ARM_VST3d8:
    case ARM_VST3d16:
    case ARM_VST3d32:
    case ARM_VST3d8_UPD:
    case ARM_VST3d16_UPD:
    case ARM_VST3d32_UPD:
    case ARM_VST4d8:
    case ARM_VST4d16:
    case ARM_VST4d32:
    case ARM_VST4d8_UPD:
    case ARM_VST4d16_UPD:
    case ARM_VST4d32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 1) % 32, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    case ARM_VST3q8:
    case ARM_VST3q16:
    case ARM_VST3q32:
    case ARM_VST3q8_UPD:
    case ARM_VST3q16_UPD:
    case ARM_VST3q32_UPD:
    case ARM_VST4q8:
    case ARM_VST4q16:
    case ARM_VST4q32:
    case ARM_VST4q8_UPD:
    case ARM_VST4q16_UPD:
    case ARM_VST4q32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 2) % 32, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  // Third input register
  switch (MCInst_getOpcode(Inst)) {
    case ARM_VST3d8:
    case ARM_VST3d16:
    case ARM_VST3d32:
    case ARM_VST3d8_UPD:
    case ARM_VST3d16_UPD:
    case ARM_VST3d32_UPD:
    case ARM_VST4d8:
    case ARM_VST4d16:
    case ARM_VST4d32:
    case ARM_VST4d8_UPD:
    case ARM_VST4d16_UPD:
    case ARM_VST4d32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 2) % 32, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    case ARM_VST3q8:
    case ARM_VST3q16:
    case ARM_VST3q32:
    case ARM_VST3q8_UPD:
    case ARM_VST3q16_UPD:
    case ARM_VST3q32_UPD:
    case ARM_VST4q8:
    case ARM_VST4q16:
    case ARM_VST4q32:
    case ARM_VST4q8_UPD:
    case ARM_VST4q16_UPD:
    case ARM_VST4q32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 4) % 32, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  // Fourth input register
  switch (MCInst_getOpcode(Inst)) {
    case ARM_VST4d8:
    case ARM_VST4d16:
    case ARM_VST4d32:
    case ARM_VST4d8_UPD:
    case ARM_VST4d16_UPD:
    case ARM_VST4d32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 3) % 32, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    case ARM_VST4q8:
    case ARM_VST4q16:
    case ARM_VST4q32:
    case ARM_VST4q8_UPD:
    case ARM_VST4q16_UPD:
    case ARM_VST4q32_UPD:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 6) % 32, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  return S;
}

static DecodeStatus DecodeVLD1DupInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn, Rm, align, size;
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  Rn = fieldFromInstruction_4(Insn, 16, 4);
  Rm = fieldFromInstruction_4(Insn, 0, 4);
  align = fieldFromInstruction_4(Insn, 4, 1);
  size = fieldFromInstruction_4(Insn, 6, 2);

  if (size == 0 && align == 1)
    return MCDisassembler_Fail;

  align *= (1 << size);

  switch (MCInst_getOpcode(Inst)) {
    case ARM_VLD1DUPq16: case ARM_VLD1DUPq32: case ARM_VLD1DUPq8:
    case ARM_VLD1DUPq16wb_fixed: case ARM_VLD1DUPq16wb_register:
    case ARM_VLD1DUPq32wb_fixed: case ARM_VLD1DUPq32wb_register:
    case ARM_VLD1DUPq8wb_fixed: case ARM_VLD1DUPq8wb_register:
      if (!Check(&S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    default:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
  }

  if (Rm != 0xF) {
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, align);

  // The fixed offset post-increment encodes Rm == 0xd. The no-writeback
  // variant encodes Rm == 0xf. Anything else is a register offset post-
  // increment and we need to add the register operand to the instruction.
  if (Rm != 0xD && Rm != 0xF &&
      !Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeVLD2DupInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn, Rm, align, size;
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  Rn = fieldFromInstruction_4(Insn, 16, 4);
  Rm = fieldFromInstruction_4(Insn, 0, 4);
  align = fieldFromInstruction_4(Insn, 4, 1);
  size = 1 << fieldFromInstruction_4(Insn, 6, 2);
  align *= 2 * size;

  switch (MCInst_getOpcode(Inst)) {
    case ARM_VLD2DUPd16: case ARM_VLD2DUPd32: case ARM_VLD2DUPd8:
    case ARM_VLD2DUPd16wb_fixed: case ARM_VLD2DUPd16wb_register:
    case ARM_VLD2DUPd32wb_fixed: case ARM_VLD2DUPd32wb_register:
    case ARM_VLD2DUPd8wb_fixed: case ARM_VLD2DUPd8wb_register:
      if (!Check(&S, DecodeDPairRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    case ARM_VLD2DUPd16x2: case ARM_VLD2DUPd32x2: case ARM_VLD2DUPd8x2:
    case ARM_VLD2DUPd16x2wb_fixed: case ARM_VLD2DUPd16x2wb_register:
    case ARM_VLD2DUPd32x2wb_fixed: case ARM_VLD2DUPd32x2wb_register:
    case ARM_VLD2DUPd8x2wb_fixed: case ARM_VLD2DUPd8x2wb_register:
      if (!Check(&S, DecodeDPairSpacedRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
      break;

    default:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
  }

  if (Rm != 0xF)
    MCOperand_CreateImm0(Inst, 0);

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, align);

  if (Rm != 0xD && Rm != 0xF) {
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  return S;
}

static DecodeStatus DecodeVLD3DupInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn, Rm, inc;
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  Rn = fieldFromInstruction_4(Insn, 16, 4);
  Rm = fieldFromInstruction_4(Insn, 0, 4);
  inc = fieldFromInstruction_4(Insn, 5, 1) + 1;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + inc) % 32, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 2*inc) % 32, Address, Decoder)))
    return MCDisassembler_Fail;

  if (Rm != 0xF) {
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, 0);

  if (Rm == 0xD)
    MCOperand_CreateReg0(Inst, 0);
  else if (Rm != 0xF) {
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  return S;
}

static DecodeStatus DecodeVLD4DupInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn, Rm, size, inc, align;
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  Rn = fieldFromInstruction_4(Insn, 16, 4);
  Rm = fieldFromInstruction_4(Insn, 0, 4);
  size = fieldFromInstruction_4(Insn, 6, 2);
  inc = fieldFromInstruction_4(Insn, 5, 1) + 1;
  align = fieldFromInstruction_4(Insn, 4, 1);

  if (size == 0x3) {
    if (align == 0)
      return MCDisassembler_Fail;
    align = 16;
  } else {
    if (size == 2) {
      align *= 8;
    } else {
      size = 1 << size;
      align *= 4 * size;
    }
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + inc) % 32, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 2*inc) % 32, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, (Rd + 3*inc) % 32, Address, Decoder)))
    return MCDisassembler_Fail;

  if (Rm != 0xF) {
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, align);

  if (Rm == 0xD)
    MCOperand_CreateReg0(Inst, 0);
  else if (Rm != 0xF) {
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  return S;
}

static DecodeStatus DecodeNEONModImmInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned imm, Q;
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  imm = fieldFromInstruction_4(Insn, 0, 4);
  imm |= fieldFromInstruction_4(Insn, 16, 3) << 4;
  imm |= fieldFromInstruction_4(Insn, 24, 1) << 7;
  imm |= fieldFromInstruction_4(Insn, 8, 4) << 8;
  imm |= fieldFromInstruction_4(Insn, 5, 1) << 12;
  Q = fieldFromInstruction_4(Insn, 6, 1);

  if (Q) {
    if (!Check(&S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
      return MCDisassembler_Fail;
  } else {
    if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  MCOperand_CreateImm0(Inst, imm);

  switch (MCInst_getOpcode(Inst)) {
    case ARM_VORRiv4i16:
    case ARM_VORRiv2i32:
    case ARM_VBICiv4i16:
    case ARM_VBICiv2i32:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    case ARM_VORRiv8i16:
    case ARM_VORRiv4i32:
    case ARM_VBICiv8i16:
    case ARM_VBICiv4i32:
      if (!Check(&S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  return S;
}

static DecodeStatus DecodeVSHLMaxInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rm, size;
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  Rm = fieldFromInstruction_4(Insn, 0, 4);
  Rm |= fieldFromInstruction_4(Insn, 5, 1) << 4;
  size = fieldFromInstruction_4(Insn, 18, 2);

  if (!Check(&S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, 8 << size);

  return S;
}

static DecodeStatus DecodeShiftRight8Imm(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  MCOperand_CreateImm0(Inst, 8 - Val);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeShiftRight16Imm(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  MCOperand_CreateImm0(Inst, 16 - Val);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeShiftRight32Imm(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  MCOperand_CreateImm0(Inst, 32 - Val);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeShiftRight64Imm(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  MCOperand_CreateImm0(Inst, 64 - Val);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeTBLInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn, Rm, op;
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  Rn = fieldFromInstruction_4(Insn, 16, 4);
  Rn |= fieldFromInstruction_4(Insn, 7, 1) << 4;
  Rm = fieldFromInstruction_4(Insn, 0, 4);
  Rm |= fieldFromInstruction_4(Insn, 5, 1) << 4;
  op = fieldFromInstruction_4(Insn, 6, 1);

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (op) {
    if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
      return MCDisassembler_Fail; // Writeback
  }

  switch (MCInst_getOpcode(Inst)) {
    case ARM_VTBL2:
    case ARM_VTBX2:
      if (!Check(&S, DecodeDPairRegisterClass(Inst, Rn, Address, Decoder)))
        return MCDisassembler_Fail;
      break;
    default:
      if (!Check(&S, DecodeDPRRegisterClass(Inst, Rn, Address, Decoder)))
        return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeThumbAddSpecialReg(MCInst *Inst, uint16_t Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned dst = fieldFromInstruction_2(Insn, 8, 3);
  unsigned imm = fieldFromInstruction_2(Insn, 0, 8);

  if (!Check(&S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder)))
    return MCDisassembler_Fail;

  switch(MCInst_getOpcode(Inst)) {
    default:
      return MCDisassembler_Fail;
    case ARM_tADR:
      break; // tADR does not explicitly represent the PC as an operand.
    case ARM_tADDrSPi:
      MCOperand_CreateReg0(Inst, ARM_SP);
      break;
  }

  MCOperand_CreateImm0(Inst, imm);

  return S;
}

static DecodeStatus DecodeThumbBROperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  MCOperand_CreateImm0(Inst, SignExtend32(Val << 1, 12));

  return MCDisassembler_Success;
}

static DecodeStatus DecodeT2BROperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  MCOperand_CreateImm0(Inst, SignExtend32(Val, 21));

  return MCDisassembler_Success;
}

static DecodeStatus DecodeThumbCmpBROperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  MCOperand_CreateImm0(Inst, Val << 1);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeThumbAddrModeRR(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn = fieldFromInstruction_4(Val, 0, 3);
  unsigned Rm = fieldFromInstruction_4(Val, 3, 3);

  if (!Check(&S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeThumbAddrModeIS(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn = fieldFromInstruction_4(Val, 0, 3);
  unsigned imm = fieldFromInstruction_4(Val, 3, 5);

  if (!Check(&S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, imm);

  return S;
}

static DecodeStatus DecodeThumbAddrModePC(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  unsigned imm = Val << 2;

  MCOperand_CreateImm0(Inst, imm);
  //tryAddingPcLoadReferenceComment(Address, (Address & ~2u) + imm + 4, Decoder);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeThumbAddrModeSP(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  MCOperand_CreateReg0(Inst, ARM_SP);
  MCOperand_CreateImm0(Inst, Val);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeT2AddrModeSOReg(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn = fieldFromInstruction_4(Val, 6, 4);
  unsigned Rm = fieldFromInstruction_4(Val, 2, 4);
  unsigned imm = fieldFromInstruction_4(Val, 0, 2);

  // Thumb stores cannot use PC as dest register.
  switch (MCInst_getOpcode(Inst)) {
    case ARM_t2STRHs:
    case ARM_t2STRBs:
    case ARM_t2STRs:
      if (Rn == 15)
        return MCDisassembler_Fail;
    default:
      break;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, imm);

  return S;
}

static DecodeStatus DecodeT2LoadShift(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned addrmode;
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  bool hasMP = ARM_getFeatureBits(Inst->csh->mode, ARM_FeatureMP);
  bool hasV7Ops = ARM_getFeatureBits(Inst->csh->mode, ARM_HasV7Ops);

  if (Rn == 15) {
    switch (MCInst_getOpcode(Inst)) {
      case ARM_t2LDRBs:
        MCInst_setOpcode(Inst, ARM_t2LDRBpci);
        break;
      case ARM_t2LDRHs:
        MCInst_setOpcode(Inst, ARM_t2LDRHpci);
        break;
      case ARM_t2LDRSHs:
        MCInst_setOpcode(Inst, ARM_t2LDRSHpci);
        break;
      case ARM_t2LDRSBs:
        MCInst_setOpcode(Inst, ARM_t2LDRSBpci);
        break;
      case ARM_t2LDRs:
        MCInst_setOpcode(Inst, ARM_t2LDRpci);
        break;
      case ARM_t2PLDs:
        MCInst_setOpcode(Inst, ARM_t2PLDpci);
        break;
      case ARM_t2PLIs:
        MCInst_setOpcode(Inst, ARM_t2PLIpci);
        break;
      default:
        return MCDisassembler_Fail;
    }

    return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
  }

  if (Rt == 15) {
    switch (MCInst_getOpcode(Inst)) {
      case ARM_t2LDRSHs:
        return MCDisassembler_Fail;
      case ARM_t2LDRHs:
        MCInst_setOpcode(Inst, ARM_t2PLDWs);
        break;
      case ARM_t2LDRSBs:
        MCInst_setOpcode(Inst, ARM_t2PLIs);
      default:
        break;
    }
  }

  switch (MCInst_getOpcode(Inst)) {
    case ARM_t2PLDs:
      break;
    case ARM_t2PLIs:
      if (!hasV7Ops)
        return MCDisassembler_Fail;
      break;
    case ARM_t2PLDWs:
      if (!hasV7Ops || !hasMP)
        return MCDisassembler_Fail;
      break;
    default:
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
        return MCDisassembler_Fail;
  }

  addrmode = fieldFromInstruction_4(Insn, 4, 2);
  addrmode |= fieldFromInstruction_4(Insn, 0, 4) << 2;
  addrmode |= fieldFromInstruction_4(Insn, 16, 4) << 6;

  if (!Check(&S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeT2LoadImm8(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void* Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned U = fieldFromInstruction_4(Insn, 9, 1);
  unsigned imm = fieldFromInstruction_4(Insn, 0, 8);
  unsigned add = fieldFromInstruction_4(Insn, 9, 1);
  bool hasMP = ARM_getFeatureBits(Inst->csh->mode, ARM_FeatureMP);
  bool hasV7Ops = ARM_getFeatureBits(Inst->csh->mode, ARM_HasV7Ops);

  imm |= (U << 8);
  imm |= (Rn << 9);

  if (Rn == 15) {
    switch (MCInst_getOpcode(Inst)) {
      case ARM_t2LDRi8:
        MCInst_setOpcode(Inst, ARM_t2LDRpci);
        break;
      case ARM_t2LDRBi8:
        MCInst_setOpcode(Inst, ARM_t2LDRBpci);
        break;
      case ARM_t2LDRSBi8:
        MCInst_setOpcode(Inst, ARM_t2LDRSBpci);
        break;
      case ARM_t2LDRHi8:
        MCInst_setOpcode(Inst, ARM_t2LDRHpci);
        break;
      case ARM_t2LDRSHi8:
        MCInst_setOpcode(Inst, ARM_t2LDRSHpci);
        break;
      case ARM_t2PLDi8:
        MCInst_setOpcode(Inst, ARM_t2PLDpci);
        break;
      case ARM_t2PLIi8:
        MCInst_setOpcode(Inst, ARM_t2PLIpci);
        break;
      default:
        return MCDisassembler_Fail;
    }

    return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
  }

  if (Rt == 15) {
    switch (MCInst_getOpcode(Inst)) {
      case ARM_t2LDRSHi8:
        return MCDisassembler_Fail;
      case ARM_t2LDRHi8:
        if (!add)
          MCInst_setOpcode(Inst, ARM_t2PLDWi8);
        break;
      case ARM_t2LDRSBi8:
        MCInst_setOpcode(Inst, ARM_t2PLIi8);
        break;
      default:
        break;
    }
  }

  switch (MCInst_getOpcode(Inst)) {
    case ARM_t2PLDi8:
      break;
    case ARM_t2PLIi8:
      if (!hasV7Ops)
        return MCDisassembler_Fail;
      break;
    case ARM_t2PLDWi8:
      if (!hasV7Ops || !hasMP)
        return MCDisassembler_Fail;
      break;
    default:
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
        return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeT2LoadImm12(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void* Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned imm = fieldFromInstruction_4(Insn, 0, 12);
  bool hasMP = ARM_getFeatureBits(Inst->csh->mode, ARM_FeatureMP);
  bool hasV7Ops = ARM_getFeatureBits(Inst->csh->mode, ARM_HasV7Ops);

  imm |= (Rn << 13);

  if (Rn == 15) {
    switch (MCInst_getOpcode(Inst)) {
      case ARM_t2LDRi12:
        MCInst_setOpcode(Inst, ARM_t2LDRpci);
        break;
      case ARM_t2LDRHi12:
        MCInst_setOpcode(Inst, ARM_t2LDRHpci);
        break;
      case ARM_t2LDRSHi12:
        MCInst_setOpcode(Inst, ARM_t2LDRSHpci);
        break;
      case ARM_t2LDRBi12:
        MCInst_setOpcode(Inst, ARM_t2LDRBpci);
        break;
      case ARM_t2LDRSBi12:
        MCInst_setOpcode(Inst, ARM_t2LDRSBpci);
        break;
      case ARM_t2PLDi12:
        MCInst_setOpcode(Inst, ARM_t2PLDpci);
        break;
      case ARM_t2PLIi12:
        MCInst_setOpcode(Inst, ARM_t2PLIpci);
        break;
      default:
        return MCDisassembler_Fail;
    }
    return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
  }

  if (Rt == 15) {
    switch (MCInst_getOpcode(Inst)) {
      case ARM_t2LDRSHi12:
        return MCDisassembler_Fail;
      case ARM_t2LDRHi12:
        MCInst_setOpcode(Inst, ARM_t2PLDWi12);
        break;
      case ARM_t2LDRSBi12:
        MCInst_setOpcode(Inst, ARM_t2PLIi12);
        break;
      default:
        break;
    }
  }

  switch (MCInst_getOpcode(Inst)) {
    case ARM_t2PLDi12:
      break;
    case ARM_t2PLIi12:
      if (!hasV7Ops)
        return MCDisassembler_Fail;
      break;
    case ARM_t2PLDWi12:
      if (!hasV7Ops || !hasMP)
        return MCDisassembler_Fail;
      break;
    default:
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
        return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeT2AddrModeImm12(Inst, imm, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeT2LoadT(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void* Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned imm = fieldFromInstruction_4(Insn, 0, 8);
  imm |= (Rn << 9);

  if (Rn == 15) {
    switch (MCInst_getOpcode(Inst)) {
      case ARM_t2LDRT:
        MCInst_setOpcode(Inst, ARM_t2LDRpci);
        break;
      case ARM_t2LDRBT:
        MCInst_setOpcode(Inst, ARM_t2LDRBpci);
        break;
      case ARM_t2LDRHT:
        MCInst_setOpcode(Inst, ARM_t2LDRHpci);
        break;
      case ARM_t2LDRSBT:
        MCInst_setOpcode(Inst, ARM_t2LDRSBpci);
        break;
      case ARM_t2LDRSHT:
        MCInst_setOpcode(Inst, ARM_t2LDRSHpci);
        break;
      default:
        return MCDisassembler_Fail;
    }

    return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
  }

  if (!Check(&S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeT2AddrModeImm8(Inst, imm, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeT2LoadLabel(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void* Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned U = fieldFromInstruction_4(Insn, 23, 1);
  int imm = fieldFromInstruction_4(Insn, 0, 12);
  bool hasV7Ops = ARM_getFeatureBits(Inst->csh->mode, ARM_HasV7Ops);

  if (Rt == 15) {
    switch (MCInst_getOpcode(Inst)) {
      case ARM_t2LDRBpci:
      case ARM_t2LDRHpci:
        MCInst_setOpcode(Inst, ARM_t2PLDpci);
        break;
      case ARM_t2LDRSBpci:
        MCInst_setOpcode(Inst, ARM_t2PLIpci);
        break;
      case ARM_t2LDRSHpci:
        return MCDisassembler_Fail;
      default:
        break;
    }
  }

  switch(MCInst_getOpcode(Inst)) {
    case ARM_t2PLDpci:
      break;
    case ARM_t2PLIpci:
      if (!hasV7Ops)
        return MCDisassembler_Fail;
      break;
    default:
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
        return MCDisassembler_Fail;
  }

  if (!U) {
    // Special case for #-0.
    if (imm == 0)
      imm = INT32_MIN;
    else
      imm = -imm;
  }

  MCOperand_CreateImm0(Inst, imm);

  return S;
}

static DecodeStatus DecodeT2Imm8S4(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  if (Val == 0)
    MCOperand_CreateImm0(Inst, INT32_MIN);
  else {
    int imm = Val & 0xFF;

    if (!(Val & 0x100)) imm *= -1;

    MCOperand_CreateImm0(Inst, imm * 4);
  }

  return MCDisassembler_Success;
}

static DecodeStatus DecodeT2AddrModeImm8s4(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn = fieldFromInstruction_4(Val, 9, 4);
  unsigned imm = fieldFromInstruction_4(Val, 0, 9);

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeT2Imm8S4(Inst, imm, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeT2AddrModeImm0_1020s4(MCInst *Inst,unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn = fieldFromInstruction_4(Val, 8, 4);
  unsigned imm = fieldFromInstruction_4(Val, 0, 8);

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, imm);

  return S;
}

static DecodeStatus DecodeT2Imm8(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  int imm = Val & 0xFF;

  if (Val == 0)
    imm = INT32_MIN;
  else if (!(Val & 0x100))
    imm *= -1;

  MCOperand_CreateImm0(Inst, imm);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeT2AddrModeImm8(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  unsigned Rn = fieldFromInstruction_4(Val, 9, 4);
  unsigned imm = fieldFromInstruction_4(Val, 0, 9);

  // Thumb stores cannot use PC as dest register.
  switch (MCInst_getOpcode(Inst)) {
    case ARM_t2STRT:
    case ARM_t2STRBT:
    case ARM_t2STRHT:
    case ARM_t2STRi8:
    case ARM_t2STRHi8:
    case ARM_t2STRBi8:
      if (Rn == 15)
        return MCDisassembler_Fail;
      break;
    default:
      break;
  }

  // Some instructions always use an additive offset.
  switch (MCInst_getOpcode(Inst)) {
    case ARM_t2LDRT:
    case ARM_t2LDRBT:
    case ARM_t2LDRHT:
    case ARM_t2LDRSBT:
    case ARM_t2LDRSHT:
    case ARM_t2STRT:
    case ARM_t2STRBT:
    case ARM_t2STRHT:
      imm |= 0x100;
      break;
    default:
      break;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeT2Imm8(Inst, imm, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeT2LdStPre(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned load;
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned addr = fieldFromInstruction_4(Insn, 0, 8);
  addr |= fieldFromInstruction_4(Insn, 9, 1) << 8;
  addr |= Rn << 9;
  load = fieldFromInstruction_4(Insn, 20, 1);

  if (Rn == 15) {
    switch (MCInst_getOpcode(Inst)) {
      case ARM_t2LDR_PRE:
      case ARM_t2LDR_POST:
        MCInst_setOpcode(Inst, ARM_t2LDRpci);
        break;
      case ARM_t2LDRB_PRE:
      case ARM_t2LDRB_POST:
        MCInst_setOpcode(Inst, ARM_t2LDRBpci);
        break;
      case ARM_t2LDRH_PRE:
      case ARM_t2LDRH_POST:
        MCInst_setOpcode(Inst, ARM_t2LDRHpci);
        break;
      case ARM_t2LDRSB_PRE:
      case ARM_t2LDRSB_POST:
        if (Rt == 15)
          MCInst_setOpcode(Inst, ARM_t2PLIpci);
        else
          MCInst_setOpcode(Inst, ARM_t2LDRSBpci);
        break;
      case ARM_t2LDRSH_PRE:
      case ARM_t2LDRSH_POST:
        MCInst_setOpcode(Inst, ARM_t2LDRSHpci);
        break;
      default:
        return MCDisassembler_Fail;
    }

    return DecodeT2LoadLabel(Inst, Insn, Address, Decoder);
  }

  if (!load) {
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  if (load) {
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeT2AddrModeImm8(Inst, addr, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeT2AddrModeImm12(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn = fieldFromInstruction_4(Val, 13, 4);
  unsigned imm = fieldFromInstruction_4(Val, 0, 12);

  // Thumb stores cannot use PC as dest register.
  switch (MCInst_getOpcode(Inst)) {
    case ARM_t2STRi12:
    case ARM_t2STRBi12:
    case ARM_t2STRHi12:
      if (Rn == 15)
        return MCDisassembler_Fail;
    default:
      break;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, imm);

  return S;
}

static DecodeStatus DecodeThumbAddSPImm(MCInst *Inst, uint16_t Insn,
    uint64_t Address, const void *Decoder)
{
  unsigned imm = fieldFromInstruction_2(Insn, 0, 7);

  MCOperand_CreateReg0(Inst, ARM_SP);
  MCOperand_CreateReg0(Inst, ARM_SP);
  MCOperand_CreateImm0(Inst, imm);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeThumbAddSPReg(MCInst *Inst, uint16_t Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  if (MCInst_getOpcode(Inst) == ARM_tADDrSP) {
    unsigned Rdm = fieldFromInstruction_2(Insn, 0, 3);
    Rdm |= fieldFromInstruction_2(Insn, 7, 1) << 3;

    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
      return MCDisassembler_Fail;

    MCOperand_CreateReg0(Inst, ARM_SP);

    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)))
      return MCDisassembler_Fail;
  } else if (MCInst_getOpcode(Inst) == ARM_tADDspr) {
    unsigned Rm = fieldFromInstruction_2(Insn, 3, 4);

    MCOperand_CreateReg0(Inst, ARM_SP);
    MCOperand_CreateReg0(Inst, ARM_SP);

    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  return S;
}

static DecodeStatus DecodeThumbCPS(MCInst *Inst, uint16_t Insn,
    uint64_t Address, const void *Decoder)
{
  unsigned imod = fieldFromInstruction_2(Insn, 4, 1) | 0x2;
  unsigned flags = fieldFromInstruction_2(Insn, 0, 3);

  MCOperand_CreateImm0(Inst, imod);
  MCOperand_CreateImm0(Inst, flags);

  return MCDisassembler_Success;
}

static DecodeStatus DecodePostIdxReg(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned add = fieldFromInstruction_4(Insn, 4, 1);

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, add);

  return S;
}

static DecodeStatus DecodeThumbBLXOffset(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  // Val is passed in as S:J1:J2:imm10H:imm10L:'0'
  // Note only one trailing zero not two.  Also the J1 and J2 values are from
  // the encoded instruction.  So here change to I1 and I2 values via:
  // I1 = NOT(J1 EOR S);
  // I2 = NOT(J2 EOR S);
  // and build the imm32 with two trailing zeros as documented:
  // imm32 = SignExtend(S:I1:I2:imm10H:imm10L:'00', 32);
  unsigned S = (Val >> 23) & 1;
  unsigned J1 = (Val >> 22) & 1;
  unsigned J2 = (Val >> 21) & 1;
  unsigned I1 = !(J1 ^ S);
  unsigned I2 = !(J2 ^ S);
  unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
  int imm32 = SignExtend32(tmp << 1, 25);

  MCOperand_CreateImm0(Inst, imm32);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeCoprocessor(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  if (Val == 0xA || Val == 0xB)
    return MCDisassembler_Fail;

  if (ARM_getFeatureBits(Inst->csh->mode, ARM_HasV8Ops) && !(Val == 14 || Val == 15))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, Val);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeThumbTableBranch(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);

  if (Rn == ARM_SP) S = MCDisassembler_SoftFail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeThumb2BCCInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned brtarget;
  unsigned pred = fieldFromInstruction_4(Insn, 22, 4);

  if (pred == 0xE || pred == 0xF) {
    unsigned imm;
    unsigned opc = fieldFromInstruction_4(Insn, 4, 28);
    switch (opc) {
      default:
        return MCDisassembler_Fail;
      case 0xf3bf8f4:
        MCInst_setOpcode(Inst, ARM_t2DSB);
        break;
      case 0xf3bf8f5:
        MCInst_setOpcode(Inst, ARM_t2DMB);
        break;
      case 0xf3bf8f6:
        MCInst_setOpcode(Inst, ARM_t2ISB);
        break;
    }

    imm = fieldFromInstruction_4(Insn, 0, 4);
    return DecodeMemBarrierOption(Inst, imm, Address, Decoder);
  }

  brtarget = fieldFromInstruction_4(Insn, 0, 11) << 1;
  brtarget |= fieldFromInstruction_4(Insn, 11, 1) << 19;
  brtarget |= fieldFromInstruction_4(Insn, 13, 1) << 18;
  brtarget |= fieldFromInstruction_4(Insn, 16, 6) << 12;
  brtarget |= fieldFromInstruction_4(Insn, 26, 1) << 20;

  if (!Check(&S, DecodeT2BROperand(Inst, brtarget, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

// Decode a shifted immediate operand.  These basically consist
// of an 8-bit value, and a 4-bit directive that specifies either
// a splat operation or a rotation.
static DecodeStatus DecodeT2SOImm(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  unsigned ctrl = fieldFromInstruction_4(Val, 10, 2);

  if (ctrl == 0) {
    unsigned byte = fieldFromInstruction_4(Val, 8, 2);
    unsigned imm = fieldFromInstruction_4(Val, 0, 8);

    switch (byte) {
      case 0:
        MCOperand_CreateImm0(Inst, imm);
        break;
      case 1:
        MCOperand_CreateImm0(Inst, (imm << 16) | imm);
        break;
      case 2:
        MCOperand_CreateImm0(Inst, (imm << 24) | (imm << 8));
        break;
      case 3:
        MCOperand_CreateImm0(Inst, (imm << 24) | (imm << 16) | (imm << 8)  |  imm);
        break;
    }
  } else {
    unsigned unrot = fieldFromInstruction_4(Val, 0, 7) | 0x80;
    unsigned rot = fieldFromInstruction_4(Val, 7, 5);
    unsigned imm = (unrot >> rot) | (unrot << ((32 - rot) & 31));

    MCOperand_CreateImm0(Inst, imm);
  }

  return MCDisassembler_Success;
}

static DecodeStatus DecodeThumbBCCTargetOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  MCOperand_CreateImm0(Inst, SignExtend32(Val << 1, 9));

  return MCDisassembler_Success;
}

static DecodeStatus DecodeThumbBLTargetOperand(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  // Val is passed in as S:J1:J2:imm10:imm11
  // Note no trailing zero after imm11.  Also the J1 and J2 values are from
  // the encoded instruction.  So here change to I1 and I2 values via:
  // I1 = NOT(J1 EOR S);
  // I2 = NOT(J2 EOR S);
  // and build the imm32 with one trailing zero as documented:
  // imm32 = SignExtend(S:I1:I2:imm10:imm11:'0', 32);
  unsigned S = (Val >> 23) & 1;
  unsigned J1 = (Val >> 22) & 1;
  unsigned J2 = (Val >> 21) & 1;
  unsigned I1 = !(J1 ^ S);
  unsigned I2 = !(J2 ^ S);
  unsigned tmp = (Val & ~0x600000) | (I1 << 22) | (I2 << 21);
  int imm32 = SignExtend32(tmp << 1, 25);

  MCOperand_CreateImm0(Inst, imm32);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeMemBarrierOption(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  if (Val & ~0xf)
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, Val);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeInstSyncBarrierOption(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  if (Val & ~0xf)
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, Val);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeMSRMask(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;

  if (ARM_getFeatureBits(Inst->csh->mode, ARM_FeatureMClass)) {
    unsigned ValLow = Val & 0xff;

    // Validate the SYSm value first.
    switch (ValLow) {
      case  0: // apsr
      case  1: // iapsr
      case  2: // eapsr
      case  3: // xpsr
      case  5: // ipsr
      case  6: // epsr
      case  7: // iepsr
      case  8: // msp
      case  9: // psp
      case 16: // primask
      case 20: // control
        break;
      case 17: // basepri
      case 18: // basepri_max
      case 19: // faultmask
        if (!ARM_getFeatureBits(Inst->csh->mode, ARM_HasV7Ops))
          // Values basepri, basepri_max and faultmask are only valid for v7m.
          return MCDisassembler_Fail;
        break;
      case 0x8a: // msplim_ns
      case 0x8b: // psplim_ns
      case 0x91: // basepri_ns
      case 0x93: // faultmask_ns
        if (!ARM_getFeatureBits(Inst->csh->mode, ARM_HasV8MMainlineOps))
          return MCDisassembler_Fail;
        // LLVM_FALLTHROUGH;
      case 10:   // msplim
      case 11:   // psplim
      case 0x88: // msp_ns
      case 0x89: // psp_ns
      case 0x90: // primask_ns
      case 0x94: // control_ns
      case 0x98: // sp_ns
        if (!ARM_getFeatureBits(Inst->csh->mode, ARM_Feature8MSecExt))
          return MCDisassembler_Fail;
        break;
      default:
        return MCDisassembler_SoftFail;
    }

    if (MCInst_getOpcode(Inst) == ARM_t2MSR_M) {
      unsigned Mask = fieldFromInstruction_4(Val, 10, 2);
      if (!ARM_getFeatureBits(Inst->csh->mode, ARM_HasV7Ops)) {
        // The ARMv6-M MSR bits {11-10} can be only 0b10, other values are
        // unpredictable.
        if (Mask != 2)
          S = MCDisassembler_SoftFail;
      } else {
        // The ARMv7-M architecture stores an additional 2-bit mask value in
        // MSR bits {11-10}. The mask is used only with apsr, iapsr, eapsr and
        // xpsr, it has to be 0b10 in other cases. Bit mask{1} indicates if
        // the NZCVQ bits should be moved by the instruction. Bit mask{0}
        // indicates the move for the GE{3:0} bits, the mask{0} bit can be set
        // only if the processor includes the DSP extension.
        if (Mask == 0 || (Mask != 2 && ValLow > 3) ||
            (!ARM_getFeatureBits(Inst->csh->mode, ARM_FeatureDSP) && (Mask & 1)))
          S = MCDisassembler_SoftFail;
      }
    }
  } else {
    // A/R class
    if (Val == 0)
      return MCDisassembler_Fail;
  }

  MCOperand_CreateImm0(Inst, Val);
  return S;
}

static DecodeStatus DecodeBankedReg(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  unsigned R = fieldFromInstruction_4(Val, 5, 1);
  unsigned SysM = fieldFromInstruction_4(Val, 0, 5);

  // The table of encodings for these banked registers comes from B9.2.3 of the
  // ARM ARM. There are patterns, but nothing regular enough to make this logic
  // neater. So by fiat, these values are UNPREDICTABLE:
  if (!lookupBankedRegByEncoding((R << 5) | SysM))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, Val);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeDoubleRegLoad(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);

  if (Rn == 0xF)
    S = MCDisassembler_SoftFail;

  if (!Check(&S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeDoubleRegStore(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rt = fieldFromInstruction_4(Insn, 0, 4);
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (Rn == 0xF || Rd == Rn || Rd == Rt || Rd == Rt + 1)
    S = MCDisassembler_SoftFail;

  if (!Check(&S, DecodeGPRPairRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeLDRPreImm(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned pred;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned imm = fieldFromInstruction_4(Insn, 0, 12);
  imm |= fieldFromInstruction_4(Insn, 16, 4) << 13;
  imm |= fieldFromInstruction_4(Insn, 23, 1) << 12;
  pred = fieldFromInstruction_4(Insn, 28, 4);

  if (Rn == 0xF || Rn == Rt) S = MCDisassembler_SoftFail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeLDRPreReg(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned pred, Rm;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned imm = fieldFromInstruction_4(Insn, 0, 12);
  imm |= fieldFromInstruction_4(Insn, 16, 4) << 13;
  imm |= fieldFromInstruction_4(Insn, 23, 1) << 12;
  pred = fieldFromInstruction_4(Insn, 28, 4);
  Rm = fieldFromInstruction_4(Insn, 0, 4);

  if (Rn == 0xF || Rn == Rt) S = MCDisassembler_SoftFail;
  if (Rm == 0xF) S = MCDisassembler_SoftFail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeSTRPreImm(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned pred;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned imm = fieldFromInstruction_4(Insn, 0, 12);
  imm |= fieldFromInstruction_4(Insn, 16, 4) << 13;
  imm |= fieldFromInstruction_4(Insn, 23, 1) << 12;
  pred = fieldFromInstruction_4(Insn, 28, 4);

  if (Rn == 0xF || Rn == Rt) S = MCDisassembler_SoftFail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeSTRPreReg(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned pred;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned imm = fieldFromInstruction_4(Insn, 0, 12);
  imm |= fieldFromInstruction_4(Insn, 16, 4) << 13;
  imm |= fieldFromInstruction_4(Insn, 23, 1) << 12;
  pred = fieldFromInstruction_4(Insn, 28, 4);

  if (Rn == 0xF || Rn == Rt) S = MCDisassembler_SoftFail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeSORegMemOperand(Inst, imm, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeVLD1LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned size, align = 0, index = 0;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  size = fieldFromInstruction_4(Insn, 10, 2);

  switch (size) {
    default:
      return MCDisassembler_Fail;
    case 0:
      if (fieldFromInstruction_4(Insn, 4, 1))
        return MCDisassembler_Fail; // UNDEFINED
      index = fieldFromInstruction_4(Insn, 5, 3);
      break;
    case 1:
      if (fieldFromInstruction_4(Insn, 5, 1))
        return MCDisassembler_Fail; // UNDEFINED
      index = fieldFromInstruction_4(Insn, 6, 2);
      if (fieldFromInstruction_4(Insn, 4, 1))
        align = 2;
      break;
    case 2:
      if (fieldFromInstruction_4(Insn, 6, 1))
        return MCDisassembler_Fail; // UNDEFINED

      index = fieldFromInstruction_4(Insn, 7, 1);

      switch (fieldFromInstruction_4(Insn, 4, 2)) {
        case 0 :
          align = 0; break;
        case 3:
          align = 4; break;
        default:
          return MCDisassembler_Fail;
      }
      break;
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (Rm != 0xF) { // Writeback
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, align);

  if (Rm != 0xF) {
    if (Rm != 0xD) {
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
        return MCDisassembler_Fail;
    } else
      MCOperand_CreateReg0(Inst, 0);
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, index);

  return S;
}

static DecodeStatus DecodeVST1LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned size, align = 0, index = 0;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  size = fieldFromInstruction_4(Insn, 10, 2);

  switch (size) {
    default:
      return MCDisassembler_Fail;
    case 0:
      if (fieldFromInstruction_4(Insn, 4, 1))
        return MCDisassembler_Fail; // UNDEFINED

      index = fieldFromInstruction_4(Insn, 5, 3);
      break;
    case 1:
      if (fieldFromInstruction_4(Insn, 5, 1))
        return MCDisassembler_Fail; // UNDEFINED

      index = fieldFromInstruction_4(Insn, 6, 2);
      if (fieldFromInstruction_4(Insn, 4, 1))
        align = 2;
      break;
    case 2:
      if (fieldFromInstruction_4(Insn, 6, 1))
        return MCDisassembler_Fail; // UNDEFINED

      index = fieldFromInstruction_4(Insn, 7, 1);

      switch (fieldFromInstruction_4(Insn, 4, 2)) {
        case 0: 
          align = 0; break;
        case 3:
          align = 4; break;
        default:
          return MCDisassembler_Fail;
      }
      break;
  }

  if (Rm != 0xF) { // Writeback
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, align);

  if (Rm != 0xF) {
    if (Rm != 0xD) {
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
        return MCDisassembler_Fail;
    } else
      MCOperand_CreateReg0(Inst, 0);
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, index);

  return S;
}

static DecodeStatus DecodeVLD2LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned size, align = 0, index = 0, inc = 1;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  size = fieldFromInstruction_4(Insn, 10, 2);

  switch (size) {
    default:
      return MCDisassembler_Fail;
    case 0:
      index = fieldFromInstruction_4(Insn, 5, 3);
      if (fieldFromInstruction_4(Insn, 4, 1))
        align = 2;
      break;
    case 1:
      index = fieldFromInstruction_4(Insn, 6, 2);
      if (fieldFromInstruction_4(Insn, 4, 1))
        align = 4;
      if (fieldFromInstruction_4(Insn, 5, 1))
        inc = 2;
      break;
    case 2:
      if (fieldFromInstruction_4(Insn, 5, 1))
        return MCDisassembler_Fail; // UNDEFINED

      index = fieldFromInstruction_4(Insn, 7, 1);
      if (fieldFromInstruction_4(Insn, 4, 1) != 0)
        align = 8;
      if (fieldFromInstruction_4(Insn, 6, 1))
        inc = 2;
      break;
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + inc, Address, Decoder)))
    return MCDisassembler_Fail;

  if (Rm != 0xF) { // Writeback
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, align);

  if (Rm != 0xF) {
    if (Rm != 0xD) {
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
        return MCDisassembler_Fail;
    } else
      MCOperand_CreateReg0(Inst, 0);
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + inc, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, index);

  return S;
}

static DecodeStatus DecodeVST2LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned size, align = 0, index = 0, inc = 1;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  size = fieldFromInstruction_4(Insn, 10, 2);

  switch (size) {
    default:
      return MCDisassembler_Fail;
    case 0:
      index = fieldFromInstruction_4(Insn, 5, 3);
      if (fieldFromInstruction_4(Insn, 4, 1))
        align = 2;
      break;
    case 1:
      index = fieldFromInstruction_4(Insn, 6, 2);
      if (fieldFromInstruction_4(Insn, 4, 1))
        align = 4;
      if (fieldFromInstruction_4(Insn, 5, 1))
        inc = 2;
      break;
    case 2:
      if (fieldFromInstruction_4(Insn, 5, 1))
        return MCDisassembler_Fail; // UNDEFINED

      index = fieldFromInstruction_4(Insn, 7, 1);
      if (fieldFromInstruction_4(Insn, 4, 1) != 0)
        align = 8;
      if (fieldFromInstruction_4(Insn, 6, 1))
        inc = 2;
      break;
  }

  if (Rm != 0xF) { // Writeback
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, align);

  if (Rm != 0xF) {
    if (Rm != 0xD) {
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
        return MCDisassembler_Fail;
    } else
      MCOperand_CreateReg0(Inst, 0);
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + inc, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, index);

  return S;
}

static DecodeStatus DecodeVLD3LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned size, align = 0, index = 0, inc = 1;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  size = fieldFromInstruction_4(Insn, 10, 2);

  switch (size) {
    default:
      return MCDisassembler_Fail;
    case 0:
      if (fieldFromInstruction_4(Insn, 4, 1))
        return MCDisassembler_Fail; // UNDEFINED
      index = fieldFromInstruction_4(Insn, 5, 3);
      break;
    case 1:
      if (fieldFromInstruction_4(Insn, 4, 1))
        return MCDisassembler_Fail; // UNDEFINED
      index = fieldFromInstruction_4(Insn, 6, 2);
      if (fieldFromInstruction_4(Insn, 5, 1))
        inc = 2;
      break;
    case 2:
      if (fieldFromInstruction_4(Insn, 4, 2))
        return MCDisassembler_Fail; // UNDEFINED
      index = fieldFromInstruction_4(Insn, 7, 1);
      if (fieldFromInstruction_4(Insn, 6, 1))
        inc = 2;
      break;
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;
  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + inc, Address, Decoder)))
    return MCDisassembler_Fail;
  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + 2*inc, Address, Decoder)))
    return MCDisassembler_Fail;

  if (Rm != 0xF) { // Writeback
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, align);

  if (Rm != 0xF) {
    if (Rm != 0xD) {
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
        return MCDisassembler_Fail;
    } else
      MCOperand_CreateReg0(Inst, 0);
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + inc, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + 2*inc, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, index);

  return S;
}

static DecodeStatus DecodeVST3LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned size, align = 0, index = 0, inc = 1;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  size = fieldFromInstruction_4(Insn, 10, 2);

  switch (size) {
    default:
      return MCDisassembler_Fail;
    case 0:
      if (fieldFromInstruction_4(Insn, 4, 1))
        return MCDisassembler_Fail; // UNDEFINED
      index = fieldFromInstruction_4(Insn, 5, 3);
      break;
    case 1:
      if (fieldFromInstruction_4(Insn, 4, 1))
        return MCDisassembler_Fail; // UNDEFINED
      index = fieldFromInstruction_4(Insn, 6, 2);
      if (fieldFromInstruction_4(Insn, 5, 1))
        inc = 2;
      break;
    case 2:
      if (fieldFromInstruction_4(Insn, 4, 2))
        return MCDisassembler_Fail; // UNDEFINED
      index = fieldFromInstruction_4(Insn, 7, 1);
      if (fieldFromInstruction_4(Insn, 6, 1))
        inc = 2;
      break;
  }

  if (Rm != 0xF) { // Writeback
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, align);

  if (Rm != 0xF) {
    if (Rm != 0xD) {
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
        return MCDisassembler_Fail;
    } else
      MCOperand_CreateReg0(Inst, 0);
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + inc, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + 2*inc, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, index);

  return S;
}

static DecodeStatus DecodeVLD4LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned size, align = 0, index = 0, inc = 1;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  size = fieldFromInstruction_4(Insn, 10, 2);

  switch (size) {
    default:
      return MCDisassembler_Fail;
    case 0:
      if (fieldFromInstruction_4(Insn, 4, 1))
        align = 4;
      index = fieldFromInstruction_4(Insn, 5, 3);
      break;
    case 1:
      if (fieldFromInstruction_4(Insn, 4, 1))
        align = 8;
      index = fieldFromInstruction_4(Insn, 6, 2);
      if (fieldFromInstruction_4(Insn, 5, 1))
        inc = 2;
      break;
    case 2:
      switch (fieldFromInstruction_4(Insn, 4, 2)) {
        case 0:
          align = 0; break;
        case 3:
          return MCDisassembler_Fail;
        default:
          align = 4 << fieldFromInstruction_4(Insn, 4, 2); break;
      }

      index = fieldFromInstruction_4(Insn, 7, 1);
      if (fieldFromInstruction_4(Insn, 6, 1))
        inc = 2;
      break;
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + inc, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + 2*inc, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + 3*inc, Address, Decoder)))
    return MCDisassembler_Fail;

  if (Rm != 0xF) { // Writeback
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, align);

  if (Rm != 0xF) {
    if (Rm != 0xD) {
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
        return MCDisassembler_Fail;
    } else
      MCOperand_CreateReg0(Inst, 0);
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + inc, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + 2*inc, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + 3*inc, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, index);

  return S;
}

static DecodeStatus DecodeVST4LN(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned size, align = 0, index = 0, inc = 1;
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm = fieldFromInstruction_4(Insn, 0, 4);
  unsigned Rd = fieldFromInstruction_4(Insn, 12, 4);
  Rd |= fieldFromInstruction_4(Insn, 22, 1) << 4;
  size = fieldFromInstruction_4(Insn, 10, 2);

  switch (size) {
    default:
      return MCDisassembler_Fail;
    case 0:
      if (fieldFromInstruction_4(Insn, 4, 1))
        align = 4;
      index = fieldFromInstruction_4(Insn, 5, 3);
      break;
    case 1:
      if (fieldFromInstruction_4(Insn, 4, 1))
        align = 8;
      index = fieldFromInstruction_4(Insn, 6, 2);
      if (fieldFromInstruction_4(Insn, 5, 1))
        inc = 2;
      break;
    case 2:
      switch (fieldFromInstruction_4(Insn, 4, 2)) {
        case 0:
          align = 0; break;
        case 3:
          return MCDisassembler_Fail;
        default:
          align = 4 << fieldFromInstruction_4(Insn, 4, 2); break;
      }

      index = fieldFromInstruction_4(Insn, 7, 1);
      if (fieldFromInstruction_4(Insn, 6, 1))
        inc = 2;
      break;
  }

  if (Rm != 0xF) { // Writeback
    if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, align);

  if (Rm != 0xF) {
    if (Rm != 0xD) {
      if (!Check(&S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
        return MCDisassembler_Fail;
    } else
      MCOperand_CreateReg0(Inst, 0);
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + inc, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + 2*inc, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Rd + 3*inc, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, index);

  return S;
}

static DecodeStatus DecodeVMOVSRR(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rt  = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rt2 = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm  = fieldFromInstruction_4(Insn,  5, 1);
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);
  Rm |= fieldFromInstruction_4(Insn, 0, 4) << 1;

  if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
    S = MCDisassembler_SoftFail;

  if (!Check(&S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeSPRRegisterClass(Inst, Rm + 1, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeVMOVRRS(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rt  = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rt2 = fieldFromInstruction_4(Insn, 16, 4);
  unsigned Rm  = fieldFromInstruction_4(Insn,  5, 1);
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);
  Rm |= fieldFromInstruction_4(Insn, 0, 4) << 1;

  if (Rt == 0xF || Rt2 == 0xF || Rm == 0x1F)
    S = MCDisassembler_SoftFail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt  , Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRRegisterClass(Inst, Rt2 , Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeSPRRegisterClass(Inst, Rm  , Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeSPRRegisterClass(Inst, Rm + 1, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeIT(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned pred = fieldFromInstruction_4(Insn, 4, 4);
  unsigned mask = fieldFromInstruction_4(Insn, 0, 4);

  if (pred == 0xF) {
    pred = 0xE;
    S = MCDisassembler_SoftFail;
  }

  if (mask == 0x0)
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, pred);
  MCOperand_CreateImm0(Inst, mask);

  return S;
}

static DecodeStatus DecodeT2LDRDPreInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rt2 = fieldFromInstruction_4(Insn, 8, 4);
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned addr = fieldFromInstruction_4(Insn, 0, 8);
  unsigned W = fieldFromInstruction_4(Insn, 21, 1);
  unsigned U = fieldFromInstruction_4(Insn, 23, 1);
  unsigned P = fieldFromInstruction_4(Insn, 24, 1);
  bool writeback = (W == 1) | (P == 0);

  addr |= (U << 8) | (Rn << 9);

  if (writeback && (Rn == Rt || Rn == Rt2))
    Check(&S, MCDisassembler_SoftFail);

  if (Rt == Rt2)
    Check(&S, MCDisassembler_SoftFail);

  // Rt
  if (!Check(&S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  // Rt2
  if (!Check(&S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
    return MCDisassembler_Fail;

  // Writeback operand
  if (!Check(&S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  // addr
  if (!Check(&S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeT2STRDPreInstruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Rt = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rt2 = fieldFromInstruction_4(Insn, 8, 4);
  unsigned Rn = fieldFromInstruction_4(Insn, 16, 4);
  unsigned addr = fieldFromInstruction_4(Insn, 0, 8);
  unsigned W = fieldFromInstruction_4(Insn, 21, 1);
  unsigned U = fieldFromInstruction_4(Insn, 23, 1);
  unsigned P = fieldFromInstruction_4(Insn, 24, 1);
  bool writeback = (W == 1) | (P == 0);

  addr |= (U << 8) | (Rn << 9);

  if (writeback && (Rn == Rt || Rn == Rt2))
    Check(&S, MCDisassembler_SoftFail);

  // Writeback operand
  if (!Check(&S, DecoderGPRRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  // Rt
  if (!Check(&S, DecoderGPRRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  // Rt2
  if (!Check(&S, DecoderGPRRegisterClass(Inst, Rt2, Address, Decoder)))
    return MCDisassembler_Fail;

  // addr
  if (!Check(&S, DecodeT2AddrModeImm8s4(Inst, addr, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeT2Adr(MCInst *Inst, uint32_t Insn,
    uint64_t Address, const void *Decoder)
{
  unsigned Val;
  unsigned sign1 = fieldFromInstruction_4(Insn, 21, 1);
  unsigned sign2 = fieldFromInstruction_4(Insn, 23, 1);

  if (sign1 != sign2) return MCDisassembler_Fail;

  Val = fieldFromInstruction_4(Insn, 0, 8);
  Val |= fieldFromInstruction_4(Insn, 12, 3) << 8;
  Val |= fieldFromInstruction_4(Insn, 26, 1) << 11;
  Val |= sign1 << 12;

  MCOperand_CreateImm0(Inst, SignExtend32(Val, 13));

  return MCDisassembler_Success;
}

static DecodeStatus DecodeT2ShifterImmOperand(MCInst *Inst, uint32_t Val,
    uint64_t Address, const void *Decoder)
{
  // Shift of "asr #32" is not allowed in Thumb2 mode.
  if (Val == 0x20)
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, Val);

  return MCDisassembler_Success;
}

static DecodeStatus DecodeSwap(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S;
  unsigned Rt   = fieldFromInstruction_4(Insn, 12, 4);
  unsigned Rt2  = fieldFromInstruction_4(Insn, 0,  4);
  unsigned Rn   = fieldFromInstruction_4(Insn, 16, 4);
  unsigned pred = fieldFromInstruction_4(Insn, 28, 4);

  if (pred == 0xF)
    return DecodeCPSInstruction(Inst, Insn, Address, Decoder);

  S = MCDisassembler_Success;

  if (Rt == Rn || Rn == Rt2)
    S = MCDisassembler_SoftFail;

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecodeVCVTD(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  bool hasFullFP16 = ARM_getFeatureBits(Inst->csh->mode, ARM_FeatureFullFP16);
  unsigned Vm, imm, cmode, op;
  unsigned Vd = (fieldFromInstruction_4(Insn, 12, 4) << 0);

  Vd |= (fieldFromInstruction_4(Insn, 22, 1) << 4);
  Vm = (fieldFromInstruction_4(Insn, 0, 4) << 0);
  Vm |= (fieldFromInstruction_4(Insn, 5, 1) << 4);
  imm = fieldFromInstruction_4(Insn, 16, 6);
  cmode = fieldFromInstruction_4(Insn, 8, 4);
  op = fieldFromInstruction_4(Insn, 5, 1);

  // If the top 3 bits of imm are clear, this is a VMOV (immediate)
  if (!(imm & 0x38)) {
    if (cmode == 0xF) {
      if (op == 1) return MCDisassembler_Fail;
      MCInst_setOpcode(Inst, ARM_VMOVv2f32);
    }

    if (hasFullFP16) {
      if (cmode == 0xE) {
        if (op == 1) {
          MCInst_setOpcode(Inst, ARM_VMOVv1i64);
        } else {
          MCInst_setOpcode(Inst, ARM_VMOVv8i8);
        }
      }

      if (cmode == 0xD) {
        if (op == 1) {
          MCInst_setOpcode(Inst, ARM_VMVNv2i32);
        } else {
          MCInst_setOpcode(Inst, ARM_VMOVv2i32);
        }
      }

      if (cmode == 0xC) {
        if (op == 1) {
          MCInst_setOpcode(Inst, ARM_VMVNv2i32);
        } else {
          MCInst_setOpcode(Inst, ARM_VMOVv2i32);
        }
      }
    }

    return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
  }

  if (!(imm & 0x20)) return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, 64 - imm);

  return S;
}

static DecodeStatus DecodeVCVTQ(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  bool hasFullFP16 = ARM_getFeatureBits(Inst->csh->mode, ARM_FeatureFullFP16);
  unsigned Vm, imm, cmode, op;
  unsigned Vd = (fieldFromInstruction_4(Insn, 12, 4) << 0);

  Vd |= (fieldFromInstruction_4(Insn, 22, 1) << 4);
  Vm = (fieldFromInstruction_4(Insn, 0, 4) << 0);
  Vm |= (fieldFromInstruction_4(Insn, 5, 1) << 4);
  imm = fieldFromInstruction_4(Insn, 16, 6);
  cmode = fieldFromInstruction_4(Insn, 8, 4);
  op = fieldFromInstruction_4(Insn, 5, 1);

  // VMOVv4f32 is ambiguous with these decodings.
  if (!(imm & 0x38) && cmode == 0xF) {
    if (op == 1) return MCDisassembler_Fail;
    MCInst_setOpcode(Inst, ARM_VMOVv4f32);
    return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
  }

  // If the top 3 bits of imm are clear, this is a VMOV (immediate)
  if (!(imm & 0x38)) {
    if (cmode == 0xF) {
      if (op == 1) return MCDisassembler_Fail;
      MCInst_setOpcode(Inst, ARM_VMOVv4f32);
    }

    if (hasFullFP16) {
      if (cmode == 0xE) {
        if (op == 1) {
          MCInst_setOpcode(Inst, ARM_VMOVv2i64);
        } else {
          MCInst_setOpcode(Inst, ARM_VMOVv16i8);
        }
      }

      if (cmode == 0xD) {
        if (op == 1) {
          MCInst_setOpcode(Inst, ARM_VMVNv4i32);
        } else {
          MCInst_setOpcode(Inst, ARM_VMOVv4i32);
        }
      }

      if (cmode == 0xC) {
        if (op == 1) {
          MCInst_setOpcode(Inst, ARM_VMVNv4i32);
        } else {
          MCInst_setOpcode(Inst, ARM_VMOVv4i32);
        }
      }
    }

    return DecodeNEONModImmInstruction(Inst, Insn, Address, Decoder);
  }

  if (!(imm & 0x20)) return MCDisassembler_Fail;

  if (!Check(&S, DecodeQPRRegisterClass(Inst, Vd, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeQPRRegisterClass(Inst, Vm, Address, Decoder)))
    return MCDisassembler_Fail;

  MCOperand_CreateImm0(Inst, 64 - imm);

  return S;
}

static DecodeStatus DecodeNEONComplexLane64Instruction(MCInst *Inst, unsigned Insn,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Vd = (fieldFromInstruction_4(Insn, 12, 4) << 0);
  unsigned Vn = (fieldFromInstruction_4(Insn, 16, 4) << 0);
  unsigned Vm = (fieldFromInstruction_4(Insn, 0, 4) << 0);
  unsigned q = (fieldFromInstruction_4(Insn, 6, 1) << 0);
  unsigned rotate = (fieldFromInstruction_4(Insn, 20, 2) << 0);

  Vd |= (fieldFromInstruction_4(Insn, 22, 1) << 4);
  Vn |= (fieldFromInstruction_4(Insn, 7, 1) << 4);
  Vm |= (fieldFromInstruction_4(Insn, 5, 1) << 4);

  if (q) {
    if (!Check(&S, DecodeQPRRegisterClass(Inst, Vd, Address, Decoder)))
      return MCDisassembler_Fail;

    if (!Check(&S, DecodeQPRRegisterClass(Inst, Vd, Address, Decoder)))
      return MCDisassembler_Fail;

    if (!Check(&S, DecodeQPRRegisterClass(Inst, Vn, Address, Decoder)))
      return MCDisassembler_Fail;
  } else {
    if (!Check(&S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
      return MCDisassembler_Fail;

    if (!Check(&S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
      return MCDisassembler_Fail;

    if (!Check(&S, DecodeDPRRegisterClass(Inst, Vn, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  if (!Check(&S, DecodeDPRRegisterClass(Inst, Vm, Address, Decoder)))
    return MCDisassembler_Fail;

  // The lane index does not have any bits in the encoding, because it can only
  // be 0.
  MCOperand_CreateImm0(Inst, 0);
  MCOperand_CreateImm0(Inst, rotate);

  return S;
}

static DecodeStatus DecodeLDR(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus S = MCDisassembler_Success;
  unsigned Cond;
  unsigned Rn = fieldFromInstruction_4(Val, 16, 4);
  unsigned Rt = fieldFromInstruction_4(Val, 12, 4);
  unsigned Rm = fieldFromInstruction_4(Val, 0, 4);

  Rm |= (fieldFromInstruction_4(Val, 23, 1) << 4);
  Cond = fieldFromInstruction_4(Val, 28, 4);

  if (fieldFromInstruction_4(Val, 8, 4) != 0 || Rn == Rt)
    S = MCDisassembler_SoftFail;

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodeAddrMode7Operand(Inst, Rn, Address, Decoder))) 
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePostIdxReg(Inst, Rm, Address, Decoder)))
    return MCDisassembler_Fail;

  if (!Check(&S, DecodePredicateOperand(Inst, Cond, Address, Decoder)))
    return MCDisassembler_Fail;

  return S;
}

static DecodeStatus DecoderForMRRC2AndMCRR2(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus result = MCDisassembler_Success;
  unsigned CRm = fieldFromInstruction_4(Val, 0, 4);
  unsigned opc1 = fieldFromInstruction_4(Val, 4, 4);
  unsigned cop = fieldFromInstruction_4(Val, 8, 4);
  unsigned Rt = fieldFromInstruction_4(Val, 12, 4);
  unsigned Rt2 = fieldFromInstruction_4(Val, 16, 4);

  if ((cop & ~0x1) == 0xa)
    return MCDisassembler_Fail;

  if (Rt == Rt2)
    result = MCDisassembler_SoftFail;

  // We have to check if the instruction is MRRC2
  // or MCRR2 when constructing the operands for
  // Inst. Reason is because MRRC2 stores to two
  // registers so it's tablegen desc has has two
  // outputs whereas MCRR doesn't store to any
  // registers so all of it's operands are listed
  // as inputs, therefore the operand order for
  // MRRC2 needs to be [Rt, Rt2, cop, opc1, CRm]
  // and MCRR2 operand order is [cop, opc1, Rt, Rt2, CRm]

  if (MCInst_getOpcode(Inst) == ARM_MRRC2) {
    if (!Check(&result, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
      return MCDisassembler_Fail;

    if (!Check(&result, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  MCOperand_CreateImm0(Inst, cop);
  MCOperand_CreateImm0(Inst, opc1);

  if (MCInst_getOpcode(Inst) == ARM_MCRR2) {
    if (!Check(&result, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder)))
      return MCDisassembler_Fail;

    if (!Check(&result, DecodeGPRnopcRegisterClass(Inst, Rt2, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  MCOperand_CreateImm0(Inst, CRm);

  return result;
}

static DecodeStatus DecodeForVMRSandVMSR(MCInst *Inst, unsigned Val,
    uint64_t Address, const void *Decoder)
{
  DecodeStatus result = MCDisassembler_Success;
  bool HasV8Ops = ARM_getFeatureBits(Inst->csh->mode, ARM_HasV8Ops);
  unsigned Rt = fieldFromInstruction_4(Val, 12, 4);

  if ((Inst->csh->mode & CS_MODE_THUMB) && !HasV8Ops)  {
    if (Rt == 13 || Rt == 15)
      result = MCDisassembler_SoftFail;

    Check(&result, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
  } else
    Check(&result, DecodeGPRnopcRegisterClass(Inst, Rt, Address, Decoder));

  if (Inst->csh->mode & CS_MODE_THUMB) {
    MCOperand_CreateImm0(Inst, ARMCC_AL);
    MCOperand_CreateReg0(Inst, 0);
  } else {
    unsigned pred = fieldFromInstruction_4(Val, 28, 4);
    if (!Check(&result, DecodePredicateOperand(Inst, pred, Address, Decoder)))
      return MCDisassembler_Fail;
  }

  return result;
}

#endif

Coverage Report

Created: 2025-08-03 07:00