runtime/vm/constants_x64.h

// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

#ifndef VM_CONSTANTS_X64_H_
#define VM_CONSTANTS_X64_H_

namespace dart {

enum Register {
  kFirstFreeCpuRegister = 0,
  RAX = 0,
  RCX = 1,
  RDX = 2,
  RBX = 3,
  RSP = 4,
  RBP = 5,
  RSI = 6,
  RDI = 7,
  R8  = 8,
  R9  = 9,
  R10 = 10,
  R11 = 11,
  R12 = 12,
  R13 = 13,
  R14 = 14,
  R15 = 15,
  kLastFreeCpuRegister = 15,
  kNumberOfCpuRegisters = 16,
  kNoRegister = -1  // Signals an illegal register.
};


enum ByteRegister {
  AL = 0,
  CL = 1,
  DL = 2,
  BL = 3,
  AH = 4,
  CH = 5,
  DH = 6,
  BH = 7,
  kNoByteRegister = -1  // Signals an illegal register.
};


enum XmmRegister {
  XMM0 = 0,
  XMM1 = 1,
  XMM2 = 2,
  XMM3 = 3,
  XMM4 = 4,
  XMM5 = 5,
  XMM6 = 6,
  XMM7 = 7,
  XMM8 = 8,
  XMM9 = 9,
  XMM10 = 10,
  XMM11 = 11,
  XMM12 = 12,
  XMM13 = 13,
  XMM14 = 14,
  XMM15 = 15,
  kNumberOfXmmRegisters = 16,
  kNoXmmRegister = -1  // Signals an illegal register.
};


// Architecture independent aliases.
typedef XmmRegister FpuRegister;
const FpuRegister FpuTMP = XMM0;
const int kNumberOfFpuRegisters = kNumberOfXmmRegisters;
const FpuRegister kNoFpuRegister = kNoXmmRegister;


enum RexBits {
  REX_NONE   = 0,
  REX_B      = 1 << 0,
  REX_X      = 1 << 1,
  REX_R      = 1 << 2,
  REX_W      = 1 << 3,
  REX_PREFIX = 1 << 6
};


// Register aliases.
const Register TMP = R11;  // Used as scratch register by the assembler.
const Register TMP2 = kNoRegister;  // No second assembler scratch register.
const Register CTX = R12;  // Location of current context at method entry.
// Caches object pool pointer in generated code.
const Register PP = R15;
const Register SPREG = RSP;  // Stack pointer register.
const Register FPREG = RBP;  // Frame pointer register.
const Register ICREG = RBX;  // IC data register.
const Register ARGS_DESC_REG = R10;  // Arguments descriptor register.
const Register CODE_REG = R12;
const Register THR = R14;  // Caches current thread in generated code.

// Exception object is passed in this register to the catch handlers when an
// exception is thrown.
const Register kExceptionObjectReg = RAX;

// Stack trace object is passed in this register to the catch handlers when
// an exception is thrown.
const Register kStackTraceObjectReg = RDX;


enum ScaleFactor {
  TIMES_1 = 0,
  TIMES_2 = 1,
  TIMES_4 = 2,
  TIMES_8 = 3,
  TIMES_16 = 4,
  TIMES_HALF_WORD_SIZE = kWordSizeLog2 - 1
};


enum Condition {
  OVERFLOW      =  0,
  NO_OVERFLOW   =  1,
  BELOW         =  2,
  ABOVE_EQUAL   =  3,
  EQUAL         =  4,
  NOT_EQUAL     =  5,
  BELOW_EQUAL   =  6,
  ABOVE         =  7,
  SIGN          =  8,
  NOT_SIGN      =  9,
  PARITY_EVEN   = 10,
  PARITY_ODD    = 11,
  LESS          = 12,
  GREATER_EQUAL = 13,
  LESS_EQUAL    = 14,
  GREATER       = 15,

  ZERO          = EQUAL,
  NOT_ZERO      = NOT_EQUAL,
  NEGATIVE      = SIGN,
  POSITIVE      = NOT_SIGN,
  CARRY         = BELOW,
  NOT_CARRY     = ABOVE_EQUAL
};

#define R(reg) (1 << (reg))

#if defined(_WIN64)
class CallingConventions {
 public:
  static const Register kArg1Reg = RCX;
  static const Register kArg2Reg = RDX;
  static const Register kArg3Reg = R8;
  static const Register kArg4Reg = R9;
  static const intptr_t kShadowSpaceBytes = 4 * kWordSize;

  static const intptr_t kVolatileCpuRegisters =
      R(RAX) | R(RCX) | R(RDX) | R(R8) | R(R9) | R(R10) | R(R11);

  static const intptr_t kVolatileXmmRegisters =
      R(XMM0) | R(XMM1) | R(XMM2) | R(XMM3) | R(XMM4) | R(XMM5);

  static const intptr_t kCalleeSaveCpuRegisters =
      R(RBX) | R(RSI) | R(RDI) | R(R12) | R(R13) | R(R14) | R(R15);

  static const intptr_t kCalleeSaveXmmRegisters =
      R(XMM6) | R(XMM7) | R(XMM8) | R(XMM9) | R(XMM10) | R(XMM11) | R(XMM12) |
      R(XMM13) | R(XMM14) | R(XMM15);

  // Windows x64 ABI specifies that small objects are passed in registers.
  // Otherwise they are passed by reference.
  static const size_t kRegisterTransferLimit = 16;
};
#else
class CallingConventions {
 public:
  static const Register kArg1Reg = RDI;
  static const Register kArg2Reg = RSI;
  static const Register kArg3Reg = RDX;
  static const Register kArg4Reg = RCX;
  static const Register kArg5Reg = R8;
  static const Register kArg6Reg = R9;
  static const intptr_t kShadowSpaceBytes = 0;

  static const intptr_t kVolatileCpuRegisters =
      R(RAX) | R(RCX) | R(RDX) | R(RSI) | R(RDI) |
      R(R8) | R(R9) | R(R10) | R(R11);

  static const intptr_t kVolatileXmmRegisters =
      R(XMM0) | R(XMM1) | R(XMM2) | R(XMM3) | R(XMM4) |
      R(XMM5) | R(XMM6) | R(XMM7) | R(XMM8) | R(XMM9) |
      R(XMM10) | R(XMM11) | R(XMM12) | R(XMM13) | R(XMM14) | R(XMM15);

  static const intptr_t kCalleeSaveCpuRegisters =
      R(RBX) | R(R12) | R(R13) | R(R14) | R(R15);

  static const intptr_t kCalleeSaveXmmRegisters = 0;
};
#endif

#undef R

class Instr {
 public:
  static const uint8_t kHltInstruction = 0xF4;
  // We prefer not to use the int3 instruction since it conflicts with gdb.
  static const uint8_t kBreakPointInstruction = kHltInstruction;
  static const int kBreakPointInstructionSize = 1;

  bool IsBreakPoint() {
    ASSERT(kBreakPointInstructionSize == 1);
    return (*reinterpret_cast<const uint8_t*>(this)) == kBreakPointInstruction;
  }

  // Instructions are read out of a code stream. The only way to get a
  // reference to an instruction is to convert a pointer. There is no way
  // to allocate or create instances of class Instr.
  // Use the At(pc) function to create references to Instr.
  static Instr* At(uword pc) { return reinterpret_cast<Instr*>(pc); }

 private:
  DISALLOW_ALLOCATION();
  // We need to prevent the creation of instances of class Instr.
  DISALLOW_IMPLICIT_CONSTRUCTORS(Instr);
};


// The largest multibyte nop we will emit.  This could go up to 15 if it
// becomes important to us.
const int MAX_NOP_SIZE = 8;

}  // namespace dart

#endif  // VM_CONSTANTS_X64_H_