Revert: [mips] Rewrite MipsAsmParser and MipsOperand.' due to buildbot errors in...
[oota-llvm.git] / lib / Target / Mips / Disassembler / MipsDisassembler.cpp
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..a543840132367e2824792d6c8e48e1dcab52b4ce 100644 (file)
@@ -0,0 +1,855 @@
+//===- MipsDisassembler.cpp - Disassembler for Mips -------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is part of the Mips Disassembler.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Mips.h"
+#include "MipsRegisterInfo.h"
+#include "MipsSubtarget.h"
+#include "llvm/MC/MCDisassembler.h"
+#include "llvm/MC/MCFixedLenDisassembler.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/MemoryObject.h"
+#include "llvm/Support/TargetRegistry.h"
+
+using namespace llvm;
+
+typedef MCDisassembler::DecodeStatus DecodeStatus;
+
+namespace {
+
+/// MipsDisassemblerBase - a disasembler class for Mips.
+class MipsDisassemblerBase : public MCDisassembler {
+public:
+  /// Constructor     - Initializes the disassembler.
+  ///
+  MipsDisassemblerBase(const MCSubtargetInfo &STI, const MCRegisterInfo *Info,
+                       bool bigEndian) :
+    MCDisassembler(STI), RegInfo(Info),
+    IsN64(STI.getFeatureBits() & Mips::FeatureN64), isBigEndian(bigEndian) {}
+
+  virtual ~MipsDisassemblerBase() {}
+
+  const MCRegisterInfo *getRegInfo() const { return RegInfo.get(); }
+
+  bool isN64() const { return IsN64; }
+
+private:
+  OwningPtr<const MCRegisterInfo> RegInfo;
+  bool IsN64;
+protected:
+  bool isBigEndian;
+};
+
+/// MipsDisassembler - a disasembler class for Mips32.
+class MipsDisassembler : public MipsDisassemblerBase {
+  bool IsMicroMips;
+public:
+  /// Constructor     - Initializes the disassembler.
+  ///
+  MipsDisassembler(const MCSubtargetInfo &STI, const MCRegisterInfo *Info,
+                   bool bigEndian) :
+    MipsDisassemblerBase(STI, Info, bigEndian) {
+      IsMicroMips = STI.getFeatureBits() & Mips::FeatureMicroMips;
+    }
+
+  /// getInstruction - See MCDisassembler.
+  virtual DecodeStatus getInstruction(MCInst &instr,
+                                      uint64_t &size,
+                                      const MemoryObject &region,
+                                      uint64_t address,
+                                      raw_ostream &vStream,
+                                      raw_ostream &cStream) const;
+};
+
+
+/// Mips64Disassembler - a disasembler class for Mips64.
+class Mips64Disassembler : public MipsDisassemblerBase {
+public:
+  /// Constructor     - Initializes the disassembler.
+  ///
+  Mips64Disassembler(const MCSubtargetInfo &STI, const MCRegisterInfo *Info,
+                     bool bigEndian) :
+    MipsDisassemblerBase(STI, Info, bigEndian) {}
+
+  /// getInstruction - See MCDisassembler.
+  virtual DecodeStatus getInstruction(MCInst &instr,
+                                      uint64_t &size,
+                                      const MemoryObject &region,
+                                      uint64_t address,
+                                      raw_ostream &vStream,
+                                      raw_ostream &cStream) const;
+};
+
+} // end anonymous namespace
+
+// Forward declare these because the autogenerated code will reference them.
+// Definitions are further down.
+static DecodeStatus DecodeGPR64RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder);
+
+static DecodeStatus DecodeCPU16RegsRegisterClass(MCInst &Inst,
+                                                 unsigned RegNo,
+                                                 uint64_t Address,
+                                                 const void *Decoder);
+
+static DecodeStatus DecodeGPR32RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder);
+
+static DecodeStatus DecodePtrRegisterClass(MCInst &Inst,
+                                           unsigned Insn,
+                                           uint64_t Address,
+                                           const void *Decoder);
+
+static DecodeStatus DecodeDSPRRegisterClass(MCInst &Inst,
+                                            unsigned RegNo,
+                                            uint64_t Address,
+                                            const void *Decoder);
+
+static DecodeStatus DecodeFGR64RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder);
+
+static DecodeStatus DecodeFGR32RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder);
+
+static DecodeStatus DecodeFGRH32RegisterClass(MCInst &Inst,
+                                              unsigned RegNo,
+                                              uint64_t Address,
+                                              const void *Decoder);
+
+static DecodeStatus DecodeCCRRegisterClass(MCInst &Inst,
+                                           unsigned RegNo,
+                                           uint64_t Address,
+                                           const void *Decoder);
+
+static DecodeStatus DecodeFCCRegisterClass(MCInst &Inst,
+                                           unsigned RegNo,
+                                           uint64_t Address,
+                                           const void *Decoder);
+
+static DecodeStatus DecodeHWRegsRegisterClass(MCInst &Inst,
+                                              unsigned Insn,
+                                              uint64_t Address,
+                                              const void *Decoder);
+
+static DecodeStatus DecodeAFGR64RegisterClass(MCInst &Inst,
+                                              unsigned RegNo,
+                                              uint64_t Address,
+                                              const void *Decoder);
+
+static DecodeStatus DecodeACC64DSPRegisterClass(MCInst &Inst,
+                                                unsigned RegNo,
+                                                uint64_t Address,
+                                                const void *Decoder);
+
+static DecodeStatus DecodeHI32DSPRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder);
+
+static DecodeStatus DecodeLO32DSPRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder);
+
+static DecodeStatus DecodeMSA128BRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder);
+
+static DecodeStatus DecodeMSA128HRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder);
+
+static DecodeStatus DecodeMSA128WRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder);
+
+static DecodeStatus DecodeMSA128DRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder);
+
+static DecodeStatus DecodeMSACtrlRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder);
+
+static DecodeStatus DecodeBranchTarget(MCInst &Inst,
+                                       unsigned Offset,
+                                       uint64_t Address,
+                                       const void *Decoder);
+
+static DecodeStatus DecodeJumpTarget(MCInst &Inst,
+                                     unsigned Insn,
+                                     uint64_t Address,
+                                     const void *Decoder);
+
+// DecodeBranchTargetMM - Decode microMIPS branch offset, which is
+// shifted left by 1 bit.
+static DecodeStatus DecodeBranchTargetMM(MCInst &Inst,
+                                         unsigned Offset,
+                                         uint64_t Address,
+                                         const void *Decoder);
+
+// DecodeJumpTargetMM - Decode microMIPS jump target, which is
+// shifted left by 1 bit.
+static DecodeStatus DecodeJumpTargetMM(MCInst &Inst,
+                                       unsigned Insn,
+                                       uint64_t Address,
+                                       const void *Decoder);
+
+static DecodeStatus DecodeMem(MCInst &Inst,
+                              unsigned Insn,
+                              uint64_t Address,
+                              const void *Decoder);
+
+static DecodeStatus DecodeMSA128Mem(MCInst &Inst, unsigned Insn,
+                                    uint64_t Address, const void *Decoder);
+
+static DecodeStatus DecodeMemMMImm12(MCInst &Inst,
+                                     unsigned Insn,
+                                     uint64_t Address,
+                                     const void *Decoder);
+
+static DecodeStatus DecodeMemMMImm16(MCInst &Inst,
+                                     unsigned Insn,
+                                     uint64_t Address,
+                                     const void *Decoder);
+
+static DecodeStatus DecodeFMem(MCInst &Inst, unsigned Insn,
+                               uint64_t Address,
+                               const void *Decoder);
+
+static DecodeStatus DecodeSimm16(MCInst &Inst,
+                                 unsigned Insn,
+                                 uint64_t Address,
+                                 const void *Decoder);
+
+// Decode the immediate field of an LSA instruction which
+// is off by one.
+static DecodeStatus DecodeLSAImm(MCInst &Inst,
+                                 unsigned Insn,
+                                 uint64_t Address,
+                                 const void *Decoder);
+
+static DecodeStatus DecodeInsSize(MCInst &Inst,
+                                  unsigned Insn,
+                                  uint64_t Address,
+                                  const void *Decoder);
+
+static DecodeStatus DecodeExtSize(MCInst &Inst,
+                                  unsigned Insn,
+                                  uint64_t Address,
+                                  const void *Decoder);
+
+namespace llvm {
+extern Target TheMipselTarget, TheMipsTarget, TheMips64Target,
+              TheMips64elTarget;
+}
+
+static MCDisassembler *createMipsDisassembler(
+                       const Target &T,
+                       const MCSubtargetInfo &STI) {
+  return new MipsDisassembler(STI, T.createMCRegInfo(""), true);
+}
+
+static MCDisassembler *createMipselDisassembler(
+                       const Target &T,
+                       const MCSubtargetInfo &STI) {
+  return new MipsDisassembler(STI, T.createMCRegInfo(""), false);
+}
+
+static MCDisassembler *createMips64Disassembler(
+                       const Target &T,
+                       const MCSubtargetInfo &STI) {
+  return new Mips64Disassembler(STI, T.createMCRegInfo(""), true);
+}
+
+static MCDisassembler *createMips64elDisassembler(
+                       const Target &T,
+                       const MCSubtargetInfo &STI) {
+  return new Mips64Disassembler(STI, T.createMCRegInfo(""), false);
+}
+
+extern "C" void LLVMInitializeMipsDisassembler() {
+  // Register the disassembler.
+  TargetRegistry::RegisterMCDisassembler(TheMipsTarget,
+                                         createMipsDisassembler);
+  TargetRegistry::RegisterMCDisassembler(TheMipselTarget,
+                                         createMipselDisassembler);
+  TargetRegistry::RegisterMCDisassembler(TheMips64Target,
+                                         createMips64Disassembler);
+  TargetRegistry::RegisterMCDisassembler(TheMips64elTarget,
+                                         createMips64elDisassembler);
+}
+
+
+#include "MipsGenDisassemblerTables.inc"
+
+  /// readInstruction - read four bytes from the MemoryObject
+  /// and return 32 bit word sorted according to the given endianess
+static DecodeStatus readInstruction32(const MemoryObject &region,
+                                      uint64_t address,
+                                      uint64_t &size,
+                                      uint32_t &insn,
+                                      bool isBigEndian,
+                                      bool IsMicroMips) {
+  uint8_t Bytes[4];
+
+  // We want to read exactly 4 Bytes of data.
+  if (region.readBytes(address, 4, Bytes) == -1) {
+    size = 0;
+    return MCDisassembler::Fail;
+  }
+
+  if (isBigEndian) {
+    // Encoded as a big-endian 32-bit word in the stream.
+    insn = (Bytes[3] <<  0) |
+           (Bytes[2] <<  8) |
+           (Bytes[1] << 16) |
+           (Bytes[0] << 24);
+  }
+  else {
+    // Encoded as a small-endian 32-bit word in the stream.
+    // Little-endian byte ordering:
+    //   mips32r2:   4 | 3 | 2 | 1
+    //   microMIPS:  2 | 1 | 4 | 3
+    if (IsMicroMips) {
+      insn = (Bytes[2] <<  0) |
+             (Bytes[3] <<  8) |
+             (Bytes[0] << 16) |
+             (Bytes[1] << 24);
+    } else {
+      insn = (Bytes[0] <<  0) |
+             (Bytes[1] <<  8) |
+             (Bytes[2] << 16) |
+             (Bytes[3] << 24);
+    }
+  }
+
+  return MCDisassembler::Success;
+}
+
+DecodeStatus
+MipsDisassembler::getInstruction(MCInst &instr,
+                                 uint64_t &Size,
+                                 const MemoryObject &Region,
+                                 uint64_t Address,
+                                 raw_ostream &vStream,
+                                 raw_ostream &cStream) const {
+  uint32_t Insn;
+
+  DecodeStatus Result = readInstruction32(Region, Address, Size,
+                                          Insn, isBigEndian, IsMicroMips);
+  if (Result == MCDisassembler::Fail)
+    return MCDisassembler::Fail;
+
+  if (IsMicroMips) {
+    // Calling the auto-generated decoder function.
+    Result = decodeInstruction(DecoderTableMicroMips32, instr, Insn, Address,
+                               this, STI);
+    if (Result != MCDisassembler::Fail) {
+      Size = 4;
+      return Result;
+    }
+    return MCDisassembler::Fail;
+  }
+
+  // Calling the auto-generated decoder function.
+  Result = decodeInstruction(DecoderTableMips32, instr, Insn, Address,
+                             this, STI);
+  if (Result != MCDisassembler::Fail) {
+    Size = 4;
+    return Result;
+  }
+
+  return MCDisassembler::Fail;
+}
+
+DecodeStatus
+Mips64Disassembler::getInstruction(MCInst &instr,
+                                   uint64_t &Size,
+                                   const MemoryObject &Region,
+                                   uint64_t Address,
+                                   raw_ostream &vStream,
+                                   raw_ostream &cStream) const {
+  uint32_t Insn;
+
+  DecodeStatus Result = readInstruction32(Region, Address, Size,
+                                          Insn, isBigEndian, false);
+  if (Result == MCDisassembler::Fail)
+    return MCDisassembler::Fail;
+
+  // Calling the auto-generated decoder function.
+  Result = decodeInstruction(DecoderTableMips6432, instr, Insn, Address,
+                             this, STI);
+  if (Result != MCDisassembler::Fail) {
+    Size = 4;
+    return Result;
+  }
+  // If we fail to decode in Mips64 decoder space we can try in Mips32
+  Result = decodeInstruction(DecoderTableMips32, instr, Insn, Address,
+                             this, STI);
+  if (Result != MCDisassembler::Fail) {
+    Size = 4;
+    return Result;
+  }
+
+  return MCDisassembler::Fail;
+}
+
+static unsigned getReg(const void *D, unsigned RC, unsigned RegNo) {
+  const MipsDisassemblerBase *Dis = static_cast<const MipsDisassemblerBase*>(D);
+  return *(Dis->getRegInfo()->getRegClass(RC).begin() + RegNo);
+}
+
+static DecodeStatus DecodeCPU16RegsRegisterClass(MCInst &Inst,
+                                                 unsigned RegNo,
+                                                 uint64_t Address,
+                                                 const void *Decoder) {
+
+  return MCDisassembler::Fail;
+
+}
+
+static DecodeStatus DecodeGPR64RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder) {
+
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::GPR64RegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeGPR32RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+  unsigned Reg = getReg(Decoder, Mips::GPR32RegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodePtrRegisterClass(MCInst &Inst,
+                                           unsigned RegNo,
+                                           uint64_t Address,
+                                           const void *Decoder) {
+  if (static_cast<const MipsDisassembler *>(Decoder)->isN64())
+    return DecodeGPR64RegisterClass(Inst, RegNo, Address, Decoder);
+
+  return DecodeGPR32RegisterClass(Inst, RegNo, Address, Decoder);
+}
+
+static DecodeStatus DecodeDSPRRegisterClass(MCInst &Inst,
+                                            unsigned RegNo,
+                                            uint64_t Address,
+                                            const void *Decoder) {
+  return DecodeGPR32RegisterClass(Inst, RegNo, Address, Decoder);
+}
+
+static DecodeStatus DecodeFGR64RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::FGR64RegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeFGR32RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::FGR32RegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeFGRH32RegisterClass(MCInst &Inst,
+                                              unsigned RegNo,
+                                              uint64_t Address,
+                                              const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::FGRH32RegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeCCRRegisterClass(MCInst &Inst,
+                                           unsigned RegNo,
+                                           uint64_t Address,
+                                           const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+  unsigned Reg = getReg(Decoder, Mips::CCRRegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeFCCRegisterClass(MCInst &Inst,
+                                           unsigned RegNo,
+                                           uint64_t Address,
+                                           const void *Decoder) {
+  if (RegNo > 7)
+    return MCDisassembler::Fail;
+  unsigned Reg = getReg(Decoder, Mips::FCCRegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeMem(MCInst &Inst,
+                              unsigned Insn,
+                              uint64_t Address,
+                              const void *Decoder) {
+  int Offset = SignExtend32<16>(Insn & 0xffff);
+  unsigned Reg = fieldFromInstruction(Insn, 16, 5);
+  unsigned Base = fieldFromInstruction(Insn, 21, 5);
+
+  Reg = getReg(Decoder, Mips::GPR32RegClassID, Reg);
+  Base = getReg(Decoder, Mips::GPR32RegClassID, Base);
+
+  if(Inst.getOpcode() == Mips::SC){
+    Inst.addOperand(MCOperand::CreateReg(Reg));
+  }
+
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  Inst.addOperand(MCOperand::CreateReg(Base));
+  Inst.addOperand(MCOperand::CreateImm(Offset));
+
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeMSA128Mem(MCInst &Inst, unsigned Insn,
+                                    uint64_t Address, const void *Decoder) {
+  int Offset = SignExtend32<10>(fieldFromInstruction(Insn, 16, 10));
+  unsigned Reg = fieldFromInstruction(Insn, 6, 5);
+  unsigned Base = fieldFromInstruction(Insn, 11, 5);
+
+  Reg = getReg(Decoder, Mips::MSA128BRegClassID, Reg);
+  Base = getReg(Decoder, Mips::GPR32RegClassID, Base);
+
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  Inst.addOperand(MCOperand::CreateReg(Base));
+
+  // The immediate field of an LD/ST instruction is scaled which means it must
+  // be multiplied (when decoding) by the size (in bytes) of the instructions'
+  // data format.
+  // .b - 1 byte
+  // .h - 2 bytes
+  // .w - 4 bytes
+  // .d - 8 bytes
+  switch(Inst.getOpcode())
+  {
+  default:
+    assert (0 && "Unexpected instruction");
+    return MCDisassembler::Fail;
+    break;
+  case Mips::LD_B:
+  case Mips::ST_B:
+    Inst.addOperand(MCOperand::CreateImm(Offset));
+    break;
+  case Mips::LD_H:
+  case Mips::ST_H:
+    Inst.addOperand(MCOperand::CreateImm(Offset << 1));
+    break;
+  case Mips::LD_W:
+  case Mips::ST_W:
+    Inst.addOperand(MCOperand::CreateImm(Offset << 2));
+    break;
+  case Mips::LD_D:
+  case Mips::ST_D:
+    Inst.addOperand(MCOperand::CreateImm(Offset << 3));
+    break;
+  }
+
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeMemMMImm12(MCInst &Inst,
+                                     unsigned Insn,
+                                     uint64_t Address,
+                                     const void *Decoder) {
+  int Offset = SignExtend32<12>(Insn & 0x0fff);
+  unsigned Reg = fieldFromInstruction(Insn, 21, 5);
+  unsigned Base = fieldFromInstruction(Insn, 16, 5);
+
+  Reg = getReg(Decoder, Mips::GPR32RegClassID, Reg);
+  Base = getReg(Decoder, Mips::GPR32RegClassID, Base);
+
+  if (Inst.getOpcode() == Mips::SC_MM)
+    Inst.addOperand(MCOperand::CreateReg(Reg));
+
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  Inst.addOperand(MCOperand::CreateReg(Base));
+  Inst.addOperand(MCOperand::CreateImm(Offset));
+
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeMemMMImm16(MCInst &Inst,
+                                     unsigned Insn,
+                                     uint64_t Address,
+                                     const void *Decoder) {
+  int Offset = SignExtend32<16>(Insn & 0xffff);
+  unsigned Reg = fieldFromInstruction(Insn, 21, 5);
+  unsigned Base = fieldFromInstruction(Insn, 16, 5);
+
+  Reg = getReg(Decoder, Mips::GPR32RegClassID, Reg);
+  Base = getReg(Decoder, Mips::GPR32RegClassID, Base);
+
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  Inst.addOperand(MCOperand::CreateReg(Base));
+  Inst.addOperand(MCOperand::CreateImm(Offset));
+
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeFMem(MCInst &Inst,
+                               unsigned Insn,
+                               uint64_t Address,
+                               const void *Decoder) {
+  int Offset = SignExtend32<16>(Insn & 0xffff);
+  unsigned Reg = fieldFromInstruction(Insn, 16, 5);
+  unsigned Base = fieldFromInstruction(Insn, 21, 5);
+
+  Reg = getReg(Decoder, Mips::FGR64RegClassID, Reg);
+  Base = getReg(Decoder, Mips::GPR32RegClassID, Base);
+
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  Inst.addOperand(MCOperand::CreateReg(Base));
+  Inst.addOperand(MCOperand::CreateImm(Offset));
+
+  return MCDisassembler::Success;
+}
+
+
+static DecodeStatus DecodeHWRegsRegisterClass(MCInst &Inst,
+                                              unsigned RegNo,
+                                              uint64_t Address,
+                                              const void *Decoder) {
+  // Currently only hardware register 29 is supported.
+  if (RegNo != 29)
+    return  MCDisassembler::Fail;
+  Inst.addOperand(MCOperand::CreateReg(Mips::HWR29));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeAFGR64RegisterClass(MCInst &Inst,
+                                              unsigned RegNo,
+                                              uint64_t Address,
+                                              const void *Decoder) {
+  if (RegNo > 30 || RegNo %2)
+    return MCDisassembler::Fail;
+
+  ;
+  unsigned Reg = getReg(Decoder, Mips::AFGR64RegClassID, RegNo /2);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeACC64DSPRegisterClass(MCInst &Inst,
+                                                unsigned RegNo,
+                                                uint64_t Address,
+                                                const void *Decoder) {
+  if (RegNo >= 4)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::ACC64DSPRegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeHI32DSPRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder) {
+  if (RegNo >= 4)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::HI32DSPRegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeLO32DSPRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder) {
+  if (RegNo >= 4)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::LO32DSPRegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeMSA128BRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::MSA128BRegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeMSA128HRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::MSA128HRegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeMSA128WRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::MSA128WRegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeMSA128DRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::MSA128DRegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeMSACtrlRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder) {
+  if (RegNo > 7)
+    return MCDisassembler::Fail;
+
+  unsigned Reg = getReg(Decoder, Mips::MSACtrlRegClassID, RegNo);
+  Inst.addOperand(MCOperand::CreateReg(Reg));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeBranchTarget(MCInst &Inst,
+                                       unsigned Offset,
+                                       uint64_t Address,
+                                       const void *Decoder) {
+  unsigned BranchOffset = Offset & 0xffff;
+  BranchOffset = SignExtend32<18>(BranchOffset << 2) + 4;
+  Inst.addOperand(MCOperand::CreateImm(BranchOffset));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeJumpTarget(MCInst &Inst,
+                                     unsigned Insn,
+                                     uint64_t Address,
+                                     const void *Decoder) {
+
+  unsigned JumpOffset = fieldFromInstruction(Insn, 0, 26) << 2;
+  Inst.addOperand(MCOperand::CreateImm(JumpOffset));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeBranchTargetMM(MCInst &Inst,
+                                         unsigned Offset,
+                                         uint64_t Address,
+                                         const void *Decoder) {
+  unsigned BranchOffset = Offset & 0xffff;
+  BranchOffset = SignExtend32<18>(BranchOffset << 1);
+  Inst.addOperand(MCOperand::CreateImm(BranchOffset));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeJumpTargetMM(MCInst &Inst,
+                                       unsigned Insn,
+                                       uint64_t Address,
+                                       const void *Decoder) {
+  unsigned JumpOffset = fieldFromInstruction(Insn, 0, 26) << 1;
+  Inst.addOperand(MCOperand::CreateImm(JumpOffset));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeSimm16(MCInst &Inst,
+                                 unsigned Insn,
+                                 uint64_t Address,
+                                 const void *Decoder) {
+  Inst.addOperand(MCOperand::CreateImm(SignExtend32<16>(Insn)));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeLSAImm(MCInst &Inst,
+                                 unsigned Insn,
+                                 uint64_t Address,
+                                 const void *Decoder) {
+  // We add one to the immediate field as it was encoded as 'imm - 1'.
+  Inst.addOperand(MCOperand::CreateImm(Insn + 1));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeInsSize(MCInst &Inst,
+                                  unsigned Insn,
+                                  uint64_t Address,
+                                  const void *Decoder) {
+  // First we need to grab the pos(lsb) from MCInst.
+  int Pos = Inst.getOperand(2).getImm();
+  int Size = (int) Insn - Pos + 1;
+  Inst.addOperand(MCOperand::CreateImm(SignExtend32<16>(Size)));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeExtSize(MCInst &Inst,
+                                  unsigned Insn,
+                                  uint64_t Address,
+                                  const void *Decoder) {
+  int Size = (int) Insn  + 1;
+  Inst.addOperand(MCOperand::CreateImm(SignExtend32<16>(Size)));
+  return MCDisassembler::Success;
+}