root/src/x64/assembler-x64.cc

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DEFINITIONS

This source file includes following definitions.
  1. Probe
  2. PatchCodeWithCall
  3. PatchCode
  4. AddressUsesRegister
  5. emit_debug_code_
  6. GetCode
  7. Align
  8. CodeTargetAlign
  9. IsNop
  10. bind_to
  11. bind
  12. GrowBuffer
  13. emit_operand
  14. arithmetic_op
  15. arithmetic_op
  16. arithmetic_op_16
  17. arithmetic_op_16
  18. arithmetic_op_32
  19. arithmetic_op_32
  20. immediate_arithmetic_op
  21. immediate_arithmetic_op
  22. immediate_arithmetic_op_16
  23. immediate_arithmetic_op_16
  24. immediate_arithmetic_op_32
  25. immediate_arithmetic_op_32
  26. immediate_arithmetic_op_8
  27. immediate_arithmetic_op_8
  28. shift
  29. shift
  30. shift_32
  31. shift_32
  32. bt
  33. bts
  34. call
  35. call
  36. call
  37. call
  38. call
  39. clc
  40. cld
  41. cdq
  42. cmovq
  43. cmovq
  44. cmovl
  45. cmovl
  46. cmpb_al
  47. cpuid
  48. cqo
  49. decq
  50. decq
  51. decl
  52. decl
  53. decb
  54. decb
  55. enter
  56. hlt
  57. idivq
  58. idivl
  59. imul
  60. imul
  61. imul
  62. imul
  63. imull
  64. imull
  65. imull
  66. incq
  67. incq
  68. incl
  69. incl
  70. int3
  71. j
  72. j
  73. jmp
  74. jmp
  75. jmp
  76. jmp
  77. lea
  78. leal
  79. load_rax
  80. load_rax
  81. leave
  82. movb
  83. movb
  84. movb
  85. movw
  86. movl
  87. movl
  88. movl
  89. movl
  90. movl
  91. movq
  92. movq
  93. movq
  94. movq
  95. movq
  96. movq
  97. movq
  98. movq
  99. movl
  100. movq
  101. movsxbq
  102. movsxwq
  103. movsxlq
  104. movsxlq
  105. movzxbq
  106. movzxbl
  107. movzxwq
  108. movzxwl
  109. repmovsb
  110. repmovsw
  111. repmovsl
  112. repmovsq
  113. mul
  114. neg
  115. negl
  116. neg
  117. nop
  118. not_
  119. not_
  120. notl
  121. Nop
  122. pop
  123. pop
  124. popfq
  125. push
  126. push
  127. push
  128. push_imm32
  129. pushfq
  130. rdtsc
  131. ret
  132. setcc
  133. shld
  134. shrd
  135. xchg
  136. store_rax
  137. store_rax
  138. testb
  139. testb
  140. testb
  141. testb
  142. testl
  143. testl
  144. testl
  145. testq
  146. testq
  147. testq
  148. fld
  149. fld1
  150. fldz
  151. fldpi
  152. fldln2
  153. fld_s
  154. fld_d
  155. fstp_s
  156. fstp_d
  157. fstp
  158. fild_s
  159. fild_d
  160. fistp_s
  161. fisttp_s
  162. fisttp_d
  163. fist_s
  164. fistp_d
  165. fabs
  166. fchs
  167. fcos
  168. fsin
  169. fptan
  170. fyl2x
  171. f2xm1
  172. fscale
  173. fninit
  174. fadd
  175. fsub
  176. fisub_s
  177. fmul
  178. fdiv
  179. faddp
  180. fsubp
  181. fsubrp
  182. fmulp
  183. fdivp
  184. fprem
  185. fprem1
  186. fxch
  187. fincstp
  188. ffree
  189. ftst
  190. fucomp
  191. fucompp
  192. fucomi
  193. fucomip
  194. fcompp
  195. fnstsw_ax
  196. fwait
  197. frndint
  198. fnclex
  199. sahf
  200. emit_farith
  201. movd
  202. movd
  203. movq
  204. movq
  205. movq
  206. movdqa
  207. movdqa
  208. extractps
  209. movsd
  210. movsd
  211. movsd
  212. movaps
  213. movapd
  214. movss
  215. movss
  216. cvttss2si
  217. cvttss2si
  218. cvttsd2si
  219. cvttsd2si
  220. cvttsd2siq
  221. cvtlsi2sd
  222. cvtlsi2sd
  223. cvtlsi2ss
  224. cvtqsi2sd
  225. cvtss2sd
  226. cvtss2sd
  227. cvtsd2ss
  228. cvtsd2si
  229. cvtsd2siq
  230. addsd
  231. mulsd
  232. subsd
  233. divsd
  234. andpd
  235. orpd
  236. xorpd
  237. xorps
  238. sqrtsd
  239. ucomisd
  240. ucomisd
  241. roundsd
  242. movmskpd
  243. emit_sse_operand
  244. emit_sse_operand
  245. emit_sse_operand
  246. emit_sse_operand
  247. db
  248. dd
  249. RecordRelocInfo
  250. RecordJSReturn
  251. RecordDebugBreakSlot
  252. RecordComment
  253. IsCodedSpecially

// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "v8.h"

#if defined(V8_TARGET_ARCH_X64)

#include "macro-assembler.h"
#include "serialize.h"

namespace v8 {
namespace internal {

// -----------------------------------------------------------------------------
// Implementation of CpuFeatures


#ifdef DEBUG
bool CpuFeatures::initialized_ = false;
#endif
uint64_t CpuFeatures::supported_ = CpuFeatures::kDefaultCpuFeatures;
uint64_t CpuFeatures::found_by_runtime_probing_ = 0;


void CpuFeatures::Probe() {
  ASSERT(supported_ == CpuFeatures::kDefaultCpuFeatures);
#ifdef DEBUG
  initialized_ = true;
#endif
  supported_ = kDefaultCpuFeatures;
  if (Serializer::enabled()) {
    supported_ |= OS::CpuFeaturesImpliedByPlatform();
    return;  // No features if we might serialize.
  }

  const int kBufferSize = 4 * KB;
  VirtualMemory* memory = new VirtualMemory(kBufferSize);
  if (!memory->IsReserved()) {
    delete memory;
    return;
  }
  ASSERT(memory->size() >= static_cast<size_t>(kBufferSize));
  if (!memory->Commit(memory->address(), kBufferSize, true/*executable*/)) {
    delete memory;
    return;
  }

  Assembler assm(NULL, memory->address(), kBufferSize);
  Label cpuid, done;
#define __ assm.
  // Save old rsp, since we are going to modify the stack.
  __ push(rbp);
  __ pushfq();
  __ push(rcx);
  __ push(rbx);
  __ movq(rbp, rsp);

  // If we can modify bit 21 of the EFLAGS register, then CPUID is supported.
  __ pushfq();
  __ pop(rax);
  __ movq(rdx, rax);
  __ xor_(rax, Immediate(0x200000));  // Flip bit 21.
  __ push(rax);
  __ popfq();
  __ pushfq();
  __ pop(rax);
  __ xor_(rax, rdx);  // Different if CPUID is supported.
  __ j(not_zero, &cpuid);

  // CPUID not supported. Clear the supported features in rax.
  __ xor_(rax, rax);
  __ jmp(&done);

  // Invoke CPUID with 1 in eax to get feature information in
  // ecx:edx. Temporarily enable CPUID support because we know it's
  // safe here.
  __ bind(&cpuid);
  __ movl(rax, Immediate(1));
  supported_ = kDefaultCpuFeatures | (1 << CPUID);
  { Scope fscope(CPUID);
    __ cpuid();
    // Move the result from ecx:edx to rdi.
    __ movl(rdi, rdx);  // Zero-extended to 64 bits.
    __ shl(rcx, Immediate(32));
    __ or_(rdi, rcx);

    // Get the sahf supported flag, from CPUID(0x80000001)
    __ movq(rax, 0x80000001, RelocInfo::NONE);
    __ cpuid();
  }
  supported_ = kDefaultCpuFeatures;

  // Put the CPU flags in rax.
  // rax = (rcx & 1) | (rdi & ~1) | (1 << CPUID).
  __ movl(rax, Immediate(1));
  __ and_(rcx, rax);  // Bit 0 is set if SAHF instruction supported.
  __ not_(rax);
  __ and_(rax, rdi);
  __ or_(rax, rcx);
  __ or_(rax, Immediate(1 << CPUID));

  // Done.
  __ bind(&done);
  __ movq(rsp, rbp);
  __ pop(rbx);
  __ pop(rcx);
  __ popfq();
  __ pop(rbp);
  __ ret(0);
#undef __

  typedef uint64_t (*F0)();
  F0 probe = FUNCTION_CAST<F0>(reinterpret_cast<Address>(memory->address()));
  supported_ = probe();
  found_by_runtime_probing_ = supported_;
  found_by_runtime_probing_ &= ~kDefaultCpuFeatures;
  uint64_t os_guarantees = OS::CpuFeaturesImpliedByPlatform();
  supported_ |= os_guarantees;
  found_by_runtime_probing_ &= ~os_guarantees;
  // SSE2 and CMOV must be available on an X64 CPU.
  ASSERT(IsSupported(CPUID));
  ASSERT(IsSupported(SSE2));
  ASSERT(IsSupported(CMOV));

  delete memory;
}


// -----------------------------------------------------------------------------
// Implementation of RelocInfo

// Patch the code at the current PC with a call to the target address.
// Additional guard int3 instructions can be added if required.
void RelocInfo::PatchCodeWithCall(Address target, int guard_bytes) {
  // Load register with immediate 64 and call through a register instructions
  // takes up 13 bytes and int3 takes up one byte.
  static const int kCallCodeSize = 13;
  int code_size = kCallCodeSize + guard_bytes;

  // Create a code patcher.
  CodePatcher patcher(pc_, code_size);

  // Add a label for checking the size of the code used for returning.
#ifdef DEBUG
  Label check_codesize;
  patcher.masm()->bind(&check_codesize);
#endif

  // Patch the code.
  patcher.masm()->movq(r10, target, RelocInfo::NONE);
  patcher.masm()->call(r10);

  // Check that the size of the code generated is as expected.
  ASSERT_EQ(kCallCodeSize,
            patcher.masm()->SizeOfCodeGeneratedSince(&check_codesize));

  // Add the requested number of int3 instructions after the call.
  for (int i = 0; i < guard_bytes; i++) {
    patcher.masm()->int3();
  }
}


void RelocInfo::PatchCode(byte* instructions, int instruction_count) {
  // Patch the code at the current address with the supplied instructions.
  for (int i = 0; i < instruction_count; i++) {
    *(pc_ + i) = *(instructions + i);
  }

  // Indicate that code has changed.
  CPU::FlushICache(pc_, instruction_count);
}


// -----------------------------------------------------------------------------
// Register constants.

const int Register::kRegisterCodeByAllocationIndex[kNumAllocatableRegisters] = {
  // rax, rbx, rdx, rcx, rdi, r8, r9, r11, r14, r15
  0, 3, 2, 1, 7, 8, 9, 11, 14, 15
};

const int Register::kAllocationIndexByRegisterCode[kNumRegisters] = {
  0, 3, 2, 1, -1, -1, -1, 4, 5, 6, -1, 7, -1, -1, 8, 9
};


// -----------------------------------------------------------------------------
// Implementation of Operand

Operand::Operand(Register base, int32_t disp) : rex_(0) {
  len_ = 1;
  if (base.is(rsp) || base.is(r12)) {
    // SIB byte is needed to encode (rsp + offset) or (r12 + offset).
    set_sib(times_1, rsp, base);
  }

  if (disp == 0 && !base.is(rbp) && !base.is(r13)) {
    set_modrm(0, base);
  } else if (is_int8(disp)) {
    set_modrm(1, base);
    set_disp8(disp);
  } else {
    set_modrm(2, base);
    set_disp32(disp);
  }
}


Operand::Operand(Register base,
                 Register index,
                 ScaleFactor scale,
                 int32_t disp) : rex_(0) {
  ASSERT(!index.is(rsp));
  len_ = 1;
  set_sib(scale, index, base);
  if (disp == 0 && !base.is(rbp) && !base.is(r13)) {
    // This call to set_modrm doesn't overwrite the REX.B (or REX.X) bits
    // possibly set by set_sib.
    set_modrm(0, rsp);
  } else if (is_int8(disp)) {
    set_modrm(1, rsp);
    set_disp8(disp);
  } else {
    set_modrm(2, rsp);
    set_disp32(disp);
  }
}


Operand::Operand(Register index,
                 ScaleFactor scale,
                 int32_t disp) : rex_(0) {
  ASSERT(!index.is(rsp));
  len_ = 1;
  set_modrm(0, rsp);
  set_sib(scale, index, rbp);
  set_disp32(disp);
}


Operand::Operand(const Operand& operand, int32_t offset) {
  ASSERT(operand.len_ >= 1);
  // Operand encodes REX ModR/M [SIB] [Disp].
  byte modrm = operand.buf_[0];
  ASSERT(modrm < 0xC0);  // Disallow mode 3 (register target).
  bool has_sib = ((modrm & 0x07) == 0x04);
  byte mode = modrm & 0xC0;
  int disp_offset = has_sib ? 2 : 1;
  int base_reg = (has_sib ? operand.buf_[1] : modrm) & 0x07;
  // Mode 0 with rbp/r13 as ModR/M or SIB base register always has a 32-bit
  // displacement.
  bool is_baseless = (mode == 0) && (base_reg == 0x05);  // No base or RIP base.
  int32_t disp_value = 0;
  if (mode == 0x80 || is_baseless) {
    // Mode 2 or mode 0 with rbp/r13 as base: Word displacement.
    disp_value = *BitCast<const int32_t*>(&operand.buf_[disp_offset]);
  } else if (mode == 0x40) {
    // Mode 1: Byte displacement.
    disp_value = static_cast<signed char>(operand.buf_[disp_offset]);
  }

  // Write new operand with same registers, but with modified displacement.
  ASSERT(offset >= 0 ? disp_value + offset > disp_value
                     : disp_value + offset < disp_value);  // No overflow.
  disp_value += offset;
  rex_ = operand.rex_;
  if (!is_int8(disp_value) || is_baseless) {
    // Need 32 bits of displacement, mode 2 or mode 1 with register rbp/r13.
    buf_[0] = (modrm & 0x3f) | (is_baseless ? 0x00 : 0x80);
    len_ = disp_offset + 4;
    Memory::int32_at(&buf_[disp_offset]) = disp_value;
  } else if (disp_value != 0 || (base_reg == 0x05)) {
    // Need 8 bits of displacement.
    buf_[0] = (modrm & 0x3f) | 0x40;  // Mode 1.
    len_ = disp_offset + 1;
    buf_[disp_offset] = static_cast<byte>(disp_value);
  } else {
    // Need no displacement.
    buf_[0] = (modrm & 0x3f);  // Mode 0.
    len_ = disp_offset;
  }
  if (has_sib) {
    buf_[1] = operand.buf_[1];
  }
}


bool Operand::AddressUsesRegister(Register reg) const {
  int code = reg.code();
  ASSERT((buf_[0] & 0xC0) != 0xC0);  // Always a memory operand.
  // Start with only low three bits of base register. Initial decoding doesn't
  // distinguish on the REX.B bit.
  int base_code = buf_[0] & 0x07;
  if (base_code == rsp.code()) {
    // SIB byte present in buf_[1].
    // Check the index register from the SIB byte + REX.X prefix.
    int index_code = ((buf_[1] >> 3) & 0x07) | ((rex_ & 0x02) << 2);
    // Index code (including REX.X) of 0x04 (rsp) means no index register.
    if (index_code != rsp.code() && index_code == code) return true;
    // Add REX.B to get the full base register code.
    base_code = (buf_[1] & 0x07) | ((rex_ & 0x01) << 3);
    // A base register of 0x05 (rbp) with mod = 0 means no base register.
    if (base_code == rbp.code() && ((buf_[0] & 0xC0) == 0)) return false;
    return code == base_code;
  } else {
    // A base register with low bits of 0x05 (rbp or r13) and mod = 0 means
    // no base register.
    if (base_code == rbp.code() && ((buf_[0] & 0xC0) == 0)) return false;
    base_code |= ((rex_ & 0x01) << 3);
    return code == base_code;
  }
}


// -----------------------------------------------------------------------------
// Implementation of Assembler.

#ifdef GENERATED_CODE_COVERAGE
static void InitCoverageLog();
#endif

Assembler::Assembler(Isolate* arg_isolate, void* buffer, int buffer_size)
    : AssemblerBase(arg_isolate),
      code_targets_(100),
      positions_recorder_(this),
      emit_debug_code_(FLAG_debug_code) {
  if (buffer == NULL) {
    // Do our own buffer management.
    if (buffer_size <= kMinimalBufferSize) {
      buffer_size = kMinimalBufferSize;

      if (isolate() != NULL && isolate()->assembler_spare_buffer() != NULL) {
        buffer = isolate()->assembler_spare_buffer();
        isolate()->set_assembler_spare_buffer(NULL);
      }
    }
    if (buffer == NULL) {
      buffer_ = NewArray<byte>(buffer_size);
    } else {
      buffer_ = static_cast<byte*>(buffer);
    }
    buffer_size_ = buffer_size;
    own_buffer_ = true;
  } else {
    // Use externally provided buffer instead.
    ASSERT(buffer_size > 0);
    buffer_ = static_cast<byte*>(buffer);
    buffer_size_ = buffer_size;
    own_buffer_ = false;
  }

  // Clear the buffer in debug mode unless it was provided by the
  // caller in which case we can't be sure it's okay to overwrite
  // existing code in it.
#ifdef DEBUG
  if (own_buffer_) {
    memset(buffer_, 0xCC, buffer_size);  // int3
  }
#endif

  // Set up buffer pointers.
  ASSERT(buffer_ != NULL);
  pc_ = buffer_;
  reloc_info_writer.Reposition(buffer_ + buffer_size, pc_);


#ifdef GENERATED_CODE_COVERAGE
  InitCoverageLog();
#endif
}


Assembler::~Assembler() {
  if (own_buffer_) {
    if (isolate() != NULL &&
        isolate()->assembler_spare_buffer() == NULL &&
        buffer_size_ == kMinimalBufferSize) {
      isolate()->set_assembler_spare_buffer(buffer_);
    } else {
      DeleteArray(buffer_);
    }
  }
}


void Assembler::GetCode(CodeDesc* desc) {
  // Finalize code (at this point overflow() may be true, but the gap ensures
  // that we are still not overlapping instructions and relocation info).
  ASSERT(pc_ <= reloc_info_writer.pos());  // No overlap.
  // Set up code descriptor.
  desc->buffer = buffer_;
  desc->buffer_size = buffer_size_;
  desc->instr_size = pc_offset();
  ASSERT(desc->instr_size > 0);  // Zero-size code objects upset the system.
  desc->reloc_size =
      static_cast<int>((buffer_ + buffer_size_) - reloc_info_writer.pos());
  desc->origin = this;
}


void Assembler::Align(int m) {
  ASSERT(IsPowerOf2(m));
  int delta = (m - (pc_offset() & (m - 1))) & (m - 1);
  Nop(delta);
}


void Assembler::CodeTargetAlign() {
  Align(16);  // Preferred alignment of jump targets on x64.
}


bool Assembler::IsNop(Address addr) {
  Address a = addr;
  while (*a == 0x66) a++;
  if (*a == 0x90) return true;
  if (a[0] == 0xf && a[1] == 0x1f) return true;
  return false;
}


void Assembler::bind_to(Label* L, int pos) {
  ASSERT(!L->is_bound());  // Label may only be bound once.
  ASSERT(0 <= pos && pos <= pc_offset());  // Position must be valid.
  if (L->is_linked()) {
    int current = L->pos();
    int next = long_at(current);
    while (next != current) {
      // Relative address, relative to point after address.
      int imm32 = pos - (current + sizeof(int32_t));
      long_at_put(current, imm32);
      current = next;
      next = long_at(next);
    }
    // Fix up last fixup on linked list.
    int last_imm32 = pos - (current + sizeof(int32_t));
    long_at_put(current, last_imm32);
  }
  while (L->is_near_linked()) {
    int fixup_pos = L->near_link_pos();
    int offset_to_next =
        static_cast<int>(*reinterpret_cast<int8_t*>(addr_at(fixup_pos)));
    ASSERT(offset_to_next <= 0);
    int disp = pos - (fixup_pos + sizeof(int8_t));
    CHECK(is_int8(disp));
    set_byte_at(fixup_pos, disp);
    if (offset_to_next < 0) {
      L->link_to(fixup_pos + offset_to_next, Label::kNear);
    } else {
      L->UnuseNear();
    }
  }
  L->bind_to(pos);
}


void Assembler::bind(Label* L) {
  bind_to(L, pc_offset());
}


void Assembler::GrowBuffer() {
  ASSERT(buffer_overflow());
  if (!own_buffer_) FATAL("external code buffer is too small");

  // Compute new buffer size.
  CodeDesc desc;  // the new buffer
  if (buffer_size_ < 4*KB) {
    desc.buffer_size = 4*KB;
  } else {
    desc.buffer_size = 2*buffer_size_;
  }
  // Some internal data structures overflow for very large buffers,
  // they must ensure that kMaximalBufferSize is not too large.
  if ((desc.buffer_size > kMaximalBufferSize) ||
      (desc.buffer_size > HEAP->MaxOldGenerationSize())) {
    V8::FatalProcessOutOfMemory("Assembler::GrowBuffer");
  }

  // Set up new buffer.
  desc.buffer = NewArray<byte>(desc.buffer_size);
  desc.instr_size = pc_offset();
  desc.reloc_size =
      static_cast<int>((buffer_ + buffer_size_) - (reloc_info_writer.pos()));

  // Clear the buffer in debug mode. Use 'int3' instructions to make
  // sure to get into problems if we ever run uninitialized code.
#ifdef DEBUG
  memset(desc.buffer, 0xCC, desc.buffer_size);
#endif

  // Copy the data.
  intptr_t pc_delta = desc.buffer - buffer_;
  intptr_t rc_delta = (desc.buffer + desc.buffer_size) -
      (buffer_ + buffer_size_);
  memmove(desc.buffer, buffer_, desc.instr_size);
  memmove(rc_delta + reloc_info_writer.pos(),
          reloc_info_writer.pos(), desc.reloc_size);

  // Switch buffers.
  if (isolate() != NULL &&
      isolate()->assembler_spare_buffer() == NULL &&
      buffer_size_ == kMinimalBufferSize) {
    isolate()->set_assembler_spare_buffer(buffer_);
  } else {
    DeleteArray(buffer_);
  }
  buffer_ = desc.buffer;
  buffer_size_ = desc.buffer_size;
  pc_ += pc_delta;
  reloc_info_writer.Reposition(reloc_info_writer.pos() + rc_delta,
                               reloc_info_writer.last_pc() + pc_delta);

  // Relocate runtime entries.
  for (RelocIterator it(desc); !it.done(); it.next()) {
    RelocInfo::Mode rmode = it.rinfo()->rmode();
    if (rmode == RelocInfo::INTERNAL_REFERENCE) {
      intptr_t* p = reinterpret_cast<intptr_t*>(it.rinfo()->pc());
      if (*p != 0) {  // 0 means uninitialized.
        *p += pc_delta;
      }
    }
  }

  ASSERT(!buffer_overflow());
}


void Assembler::emit_operand(int code, const Operand& adr) {
  ASSERT(is_uint3(code));
  const unsigned length = adr.len_;
  ASSERT(length > 0);

  // Emit updated ModR/M byte containing the given register.
  ASSERT((adr.buf_[0] & 0x38) == 0);
  pc_[0] = adr.buf_[0] | code << 3;

  // Emit the rest of the encoded operand.
  for (unsigned i = 1; i < length; i++) pc_[i] = adr.buf_[i];
  pc_ += length;
}


// Assembler Instruction implementations.

void Assembler::arithmetic_op(byte opcode, Register reg, const Operand& op) {
  EnsureSpace ensure_space(this);
  emit_rex_64(reg, op);
  emit(opcode);
  emit_operand(reg, op);
}


void Assembler::arithmetic_op(byte opcode, Register reg, Register rm_reg) {
  EnsureSpace ensure_space(this);
  ASSERT((opcode & 0xC6) == 2);
  if (rm_reg.low_bits() == 4)  {  // Forces SIB byte.
    // Swap reg and rm_reg and change opcode operand order.
    emit_rex_64(rm_reg, reg);
    emit(opcode ^ 0x02);
    emit_modrm(rm_reg, reg);
  } else {
    emit_rex_64(reg, rm_reg);
    emit(opcode);
    emit_modrm(reg, rm_reg);
  }
}


void Assembler::arithmetic_op_16(byte opcode, Register reg, Register rm_reg) {
  EnsureSpace ensure_space(this);
  ASSERT((opcode & 0xC6) == 2);
  if (rm_reg.low_bits() == 4) {  // Forces SIB byte.
    // Swap reg and rm_reg and change opcode operand order.
    emit(0x66);
    emit_optional_rex_32(rm_reg, reg);
    emit(opcode ^ 0x02);
    emit_modrm(rm_reg, reg);
  } else {
    emit(0x66);
    emit_optional_rex_32(reg, rm_reg);
    emit(opcode);
    emit_modrm(reg, rm_reg);
  }
}


void Assembler::arithmetic_op_16(byte opcode,
                                 Register reg,
                                 const Operand& rm_reg) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(reg, rm_reg);
  emit(opcode);
  emit_operand(reg, rm_reg);
}


void Assembler::arithmetic_op_32(byte opcode, Register reg, Register rm_reg) {
  EnsureSpace ensure_space(this);
  ASSERT((opcode & 0xC6) == 2);
  if (rm_reg.low_bits() == 4) {  // Forces SIB byte.
    // Swap reg and rm_reg and change opcode operand order.
    emit_optional_rex_32(rm_reg, reg);
    emit(opcode ^ 0x02);  // E.g. 0x03 -> 0x01 for ADD.
    emit_modrm(rm_reg, reg);
  } else {
    emit_optional_rex_32(reg, rm_reg);
    emit(opcode);
    emit_modrm(reg, rm_reg);
  }
}


void Assembler::arithmetic_op_32(byte opcode,
                                 Register reg,
                                 const Operand& rm_reg) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(reg, rm_reg);
  emit(opcode);
  emit_operand(reg, rm_reg);
}


void Assembler::immediate_arithmetic_op(byte subcode,
                                        Register dst,
                                        Immediate src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  if (is_int8(src.value_)) {
    emit(0x83);
    emit_modrm(subcode, dst);
    emit(src.value_);
  } else if (dst.is(rax)) {
    emit(0x05 | (subcode << 3));
    emitl(src.value_);
  } else {
    emit(0x81);
    emit_modrm(subcode, dst);
    emitl(src.value_);
  }
}

void Assembler::immediate_arithmetic_op(byte subcode,
                                        const Operand& dst,
                                        Immediate src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  if (is_int8(src.value_)) {
    emit(0x83);
    emit_operand(subcode, dst);
    emit(src.value_);
  } else {
    emit(0x81);
    emit_operand(subcode, dst);
    emitl(src.value_);
  }
}


void Assembler::immediate_arithmetic_op_16(byte subcode,
                                           Register dst,
                                           Immediate src) {
  EnsureSpace ensure_space(this);
  emit(0x66);  // Operand size override prefix.
  emit_optional_rex_32(dst);
  if (is_int8(src.value_)) {
    emit(0x83);
    emit_modrm(subcode, dst);
    emit(src.value_);
  } else if (dst.is(rax)) {
    emit(0x05 | (subcode << 3));
    emitw(src.value_);
  } else {
    emit(0x81);
    emit_modrm(subcode, dst);
    emitw(src.value_);
  }
}


void Assembler::immediate_arithmetic_op_16(byte subcode,
                                           const Operand& dst,
                                           Immediate src) {
  EnsureSpace ensure_space(this);
  emit(0x66);  // Operand size override prefix.
  emit_optional_rex_32(dst);
  if (is_int8(src.value_)) {
    emit(0x83);
    emit_operand(subcode, dst);
    emit(src.value_);
  } else {
    emit(0x81);
    emit_operand(subcode, dst);
    emitw(src.value_);
  }
}


void Assembler::immediate_arithmetic_op_32(byte subcode,
                                           Register dst,
                                           Immediate src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  if (is_int8(src.value_)) {
    emit(0x83);
    emit_modrm(subcode, dst);
    emit(src.value_);
  } else if (dst.is(rax)) {
    emit(0x05 | (subcode << 3));
    emitl(src.value_);
  } else {
    emit(0x81);
    emit_modrm(subcode, dst);
    emitl(src.value_);
  }
}


void Assembler::immediate_arithmetic_op_32(byte subcode,
                                           const Operand& dst,
                                           Immediate src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  if (is_int8(src.value_)) {
    emit(0x83);
    emit_operand(subcode, dst);
    emit(src.value_);
  } else {
    emit(0x81);
    emit_operand(subcode, dst);
    emitl(src.value_);
  }
}


void Assembler::immediate_arithmetic_op_8(byte subcode,
                                          const Operand& dst,
                                          Immediate src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  ASSERT(is_int8(src.value_) || is_uint8(src.value_));
  emit(0x80);
  emit_operand(subcode, dst);
  emit(src.value_);
}


void Assembler::immediate_arithmetic_op_8(byte subcode,
                                          Register dst,
                                          Immediate src) {
  EnsureSpace ensure_space(this);
  if (!dst.is_byte_register()) {
    // Use 64-bit mode byte registers.
    emit_rex_64(dst);
  }
  ASSERT(is_int8(src.value_) || is_uint8(src.value_));
  emit(0x80);
  emit_modrm(subcode, dst);
  emit(src.value_);
}


void Assembler::shift(Register dst, Immediate shift_amount, int subcode) {
  EnsureSpace ensure_space(this);
  ASSERT(is_uint6(shift_amount.value_));  // illegal shift count
  if (shift_amount.value_ == 1) {
    emit_rex_64(dst);
    emit(0xD1);
    emit_modrm(subcode, dst);
  } else {
    emit_rex_64(dst);
    emit(0xC1);
    emit_modrm(subcode, dst);
    emit(shift_amount.value_);
  }
}


void Assembler::shift(Register dst, int subcode) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xD3);
  emit_modrm(subcode, dst);
}


void Assembler::shift_32(Register dst, int subcode) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0xD3);
  emit_modrm(subcode, dst);
}


void Assembler::shift_32(Register dst, Immediate shift_amount, int subcode) {
  EnsureSpace ensure_space(this);
  ASSERT(is_uint5(shift_amount.value_));  // illegal shift count
  if (shift_amount.value_ == 1) {
    emit_optional_rex_32(dst);
    emit(0xD1);
    emit_modrm(subcode, dst);
  } else {
    emit_optional_rex_32(dst);
    emit(0xC1);
    emit_modrm(subcode, dst);
    emit(shift_amount.value_);
  }
}


void Assembler::bt(const Operand& dst, Register src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(src, dst);
  emit(0x0F);
  emit(0xA3);
  emit_operand(src, dst);
}


void Assembler::bts(const Operand& dst, Register src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(src, dst);
  emit(0x0F);
  emit(0xAB);
  emit_operand(src, dst);
}


void Assembler::call(Label* L) {
  positions_recorder()->WriteRecordedPositions();
  EnsureSpace ensure_space(this);
  // 1110 1000 #32-bit disp.
  emit(0xE8);
  if (L->is_bound()) {
    int offset = L->pos() - pc_offset() - sizeof(int32_t);
    ASSERT(offset <= 0);
    emitl(offset);
  } else if (L->is_linked()) {
    emitl(L->pos());
    L->link_to(pc_offset() - sizeof(int32_t));
  } else {
    ASSERT(L->is_unused());
    int32_t current = pc_offset();
    emitl(current);
    L->link_to(current);
  }
}


void Assembler::call(Handle<Code> target,
                     RelocInfo::Mode rmode,
                     unsigned ast_id) {
  positions_recorder()->WriteRecordedPositions();
  EnsureSpace ensure_space(this);
  // 1110 1000 #32-bit disp.
  emit(0xE8);
  emit_code_target(target, rmode, ast_id);
}


void Assembler::call(Register adr) {
  positions_recorder()->WriteRecordedPositions();
  EnsureSpace ensure_space(this);
  // Opcode: FF /2 r64.
  emit_optional_rex_32(adr);
  emit(0xFF);
  emit_modrm(0x2, adr);
}


void Assembler::call(const Operand& op) {
  positions_recorder()->WriteRecordedPositions();
  EnsureSpace ensure_space(this);
  // Opcode: FF /2 m64.
  emit_optional_rex_32(op);
  emit(0xFF);
  emit_operand(0x2, op);
}


// Calls directly to the given address using a relative offset.
// Should only ever be used in Code objects for calls within the
// same Code object. Should not be used when generating new code (use labels),
// but only when patching existing code.
void Assembler::call(Address target) {
  positions_recorder()->WriteRecordedPositions();
  EnsureSpace ensure_space(this);
  // 1110 1000 #32-bit disp.
  emit(0xE8);
  Address source = pc_ + 4;
  intptr_t displacement = target - source;
  ASSERT(is_int32(displacement));
  emitl(static_cast<int32_t>(displacement));
}


void Assembler::clc() {
  EnsureSpace ensure_space(this);
  emit(0xF8);
}

void Assembler::cld() {
  EnsureSpace ensure_space(this);
  emit(0xFC);
}

void Assembler::cdq() {
  EnsureSpace ensure_space(this);
  emit(0x99);
}


void Assembler::cmovq(Condition cc, Register dst, Register src) {
  if (cc == always) {
    movq(dst, src);
  } else if (cc == never) {
    return;
  }
  // No need to check CpuInfo for CMOV support, it's a required part of the
  // 64-bit architecture.
  ASSERT(cc >= 0);  // Use mov for unconditional moves.
  EnsureSpace ensure_space(this);
  // Opcode: REX.W 0f 40 + cc /r.
  emit_rex_64(dst, src);
  emit(0x0f);
  emit(0x40 + cc);
  emit_modrm(dst, src);
}


void Assembler::cmovq(Condition cc, Register dst, const Operand& src) {
  if (cc == always) {
    movq(dst, src);
  } else if (cc == never) {
    return;
  }
  ASSERT(cc >= 0);
  EnsureSpace ensure_space(this);
  // Opcode: REX.W 0f 40 + cc /r.
  emit_rex_64(dst, src);
  emit(0x0f);
  emit(0x40 + cc);
  emit_operand(dst, src);
}


void Assembler::cmovl(Condition cc, Register dst, Register src) {
  if (cc == always) {
    movl(dst, src);
  } else if (cc == never) {
    return;
  }
  ASSERT(cc >= 0);
  EnsureSpace ensure_space(this);
  // Opcode: 0f 40 + cc /r.
  emit_optional_rex_32(dst, src);
  emit(0x0f);
  emit(0x40 + cc);
  emit_modrm(dst, src);
}


void Assembler::cmovl(Condition cc, Register dst, const Operand& src) {
  if (cc == always) {
    movl(dst, src);
  } else if (cc == never) {
    return;
  }
  ASSERT(cc >= 0);
  EnsureSpace ensure_space(this);
  // Opcode: 0f 40 + cc /r.
  emit_optional_rex_32(dst, src);
  emit(0x0f);
  emit(0x40 + cc);
  emit_operand(dst, src);
}


void Assembler::cmpb_al(Immediate imm8) {
  ASSERT(is_int8(imm8.value_) || is_uint8(imm8.value_));
  EnsureSpace ensure_space(this);
  emit(0x3c);
  emit(imm8.value_);
}


void Assembler::cpuid() {
  ASSERT(CpuFeatures::IsEnabled(CPUID));
  EnsureSpace ensure_space(this);
  emit(0x0F);
  emit(0xA2);
}


void Assembler::cqo() {
  EnsureSpace ensure_space(this);
  emit_rex_64();
  emit(0x99);
}


void Assembler::decq(Register dst) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xFF);
  emit_modrm(0x1, dst);
}


void Assembler::decq(const Operand& dst) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xFF);
  emit_operand(1, dst);
}


void Assembler::decl(Register dst) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0xFF);
  emit_modrm(0x1, dst);
}


void Assembler::decl(const Operand& dst) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0xFF);
  emit_operand(1, dst);
}


void Assembler::decb(Register dst) {
  EnsureSpace ensure_space(this);
  if (!dst.is_byte_register()) {
    // Register is not one of al, bl, cl, dl.  Its encoding needs REX.
    emit_rex_32(dst);
  }
  emit(0xFE);
  emit_modrm(0x1, dst);
}


void Assembler::decb(const Operand& dst) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0xFE);
  emit_operand(1, dst);
}


void Assembler::enter(Immediate size) {
  EnsureSpace ensure_space(this);
  emit(0xC8);
  emitw(size.value_);  // 16 bit operand, always.
  emit(0);
}


void Assembler::hlt() {
  EnsureSpace ensure_space(this);
  emit(0xF4);
}


void Assembler::idivq(Register src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(src);
  emit(0xF7);
  emit_modrm(0x7, src);
}


void Assembler::idivl(Register src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(src);
  emit(0xF7);
  emit_modrm(0x7, src);
}


void Assembler::imul(Register src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(src);
  emit(0xF7);
  emit_modrm(0x5, src);
}


void Assembler::imul(Register dst, Register src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst, src);
  emit(0x0F);
  emit(0xAF);
  emit_modrm(dst, src);
}


void Assembler::imul(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst, src);
  emit(0x0F);
  emit(0xAF);
  emit_operand(dst, src);
}


void Assembler::imul(Register dst, Register src, Immediate imm) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst, src);
  if (is_int8(imm.value_)) {
    emit(0x6B);
    emit_modrm(dst, src);
    emit(imm.value_);
  } else {
    emit(0x69);
    emit_modrm(dst, src);
    emitl(imm.value_);
  }
}


void Assembler::imull(Register dst, Register src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0xAF);
  emit_modrm(dst, src);
}


void Assembler::imull(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0xAF);
  emit_operand(dst, src);
}


void Assembler::imull(Register dst, Register src, Immediate imm) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst, src);
  if (is_int8(imm.value_)) {
    emit(0x6B);
    emit_modrm(dst, src);
    emit(imm.value_);
  } else {
    emit(0x69);
    emit_modrm(dst, src);
    emitl(imm.value_);
  }
}


void Assembler::incq(Register dst) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xFF);
  emit_modrm(0x0, dst);
}


void Assembler::incq(const Operand& dst) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xFF);
  emit_operand(0, dst);
}


void Assembler::incl(const Operand& dst) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0xFF);
  emit_operand(0, dst);
}


void Assembler::incl(Register dst) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0xFF);
  emit_modrm(0, dst);
}


void Assembler::int3() {
  EnsureSpace ensure_space(this);
  emit(0xCC);
}


void Assembler::j(Condition cc, Label* L, Label::Distance distance) {
  if (cc == always) {
    jmp(L);
    return;
  } else if (cc == never) {
    return;
  }
  EnsureSpace ensure_space(this);
  ASSERT(is_uint4(cc));
  if (L->is_bound()) {
    const int short_size = 2;
    const int long_size  = 6;
    int offs = L->pos() - pc_offset();
    ASSERT(offs <= 0);
    if (is_int8(offs - short_size)) {
      // 0111 tttn #8-bit disp.
      emit(0x70 | cc);
      emit((offs - short_size) & 0xFF);
    } else {
      // 0000 1111 1000 tttn #32-bit disp.
      emit(0x0F);
      emit(0x80 | cc);
      emitl(offs - long_size);
    }
  } else if (distance == Label::kNear) {
    // 0111 tttn #8-bit disp
    emit(0x70 | cc);
    byte disp = 0x00;
    if (L->is_near_linked()) {
      int offset = L->near_link_pos() - pc_offset();
      ASSERT(is_int8(offset));
      disp = static_cast<byte>(offset & 0xFF);
    }
    L->link_to(pc_offset(), Label::kNear);
    emit(disp);
  } else if (L->is_linked()) {
    // 0000 1111 1000 tttn #32-bit disp.
    emit(0x0F);
    emit(0x80 | cc);
    emitl(L->pos());
    L->link_to(pc_offset() - sizeof(int32_t));
  } else {
    ASSERT(L->is_unused());
    emit(0x0F);
    emit(0x80 | cc);
    int32_t current = pc_offset();
    emitl(current);
    L->link_to(current);
  }
}


void Assembler::j(Condition cc,
                  Handle<Code> target,
                  RelocInfo::Mode rmode) {
  EnsureSpace ensure_space(this);
  ASSERT(is_uint4(cc));
  // 0000 1111 1000 tttn #32-bit disp.
  emit(0x0F);
  emit(0x80 | cc);
  emit_code_target(target, rmode);
}


void Assembler::jmp(Label* L, Label::Distance distance) {
  EnsureSpace ensure_space(this);
  const int short_size = sizeof(int8_t);
  const int long_size = sizeof(int32_t);
  if (L->is_bound()) {
    int offs = L->pos() - pc_offset() - 1;
    ASSERT(offs <= 0);
    if (is_int8(offs - short_size)) {
      // 1110 1011 #8-bit disp.
      emit(0xEB);
      emit((offs - short_size) & 0xFF);
    } else {
      // 1110 1001 #32-bit disp.
      emit(0xE9);
      emitl(offs - long_size);
    }
  } else if (distance == Label::kNear) {
    emit(0xEB);
    byte disp = 0x00;
    if (L->is_near_linked()) {
      int offset = L->near_link_pos() - pc_offset();
      ASSERT(is_int8(offset));
      disp = static_cast<byte>(offset & 0xFF);
    }
    L->link_to(pc_offset(), Label::kNear);
    emit(disp);
  } else if (L->is_linked()) {
    // 1110 1001 #32-bit disp.
    emit(0xE9);
    emitl(L->pos());
    L->link_to(pc_offset() - long_size);
  } else {
    // 1110 1001 #32-bit disp.
    ASSERT(L->is_unused());
    emit(0xE9);
    int32_t current = pc_offset();
    emitl(current);
    L->link_to(current);
  }
}


void Assembler::jmp(Handle<Code> target, RelocInfo::Mode rmode) {
  EnsureSpace ensure_space(this);
  // 1110 1001 #32-bit disp.
  emit(0xE9);
  emit_code_target(target, rmode);
}


void Assembler::jmp(Register target) {
  EnsureSpace ensure_space(this);
  // Opcode FF/4 r64.
  emit_optional_rex_32(target);
  emit(0xFF);
  emit_modrm(0x4, target);
}


void Assembler::jmp(const Operand& src) {
  EnsureSpace ensure_space(this);
  // Opcode FF/4 m64.
  emit_optional_rex_32(src);
  emit(0xFF);
  emit_operand(0x4, src);
}


void Assembler::lea(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst, src);
  emit(0x8D);
  emit_operand(dst, src);
}


void Assembler::leal(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst, src);
  emit(0x8D);
  emit_operand(dst, src);
}


void Assembler::load_rax(void* value, RelocInfo::Mode mode) {
  EnsureSpace ensure_space(this);
  emit(0x48);  // REX.W
  emit(0xA1);
  emitq(reinterpret_cast<uintptr_t>(value), mode);
}


void Assembler::load_rax(ExternalReference ref) {
  load_rax(ref.address(), RelocInfo::EXTERNAL_REFERENCE);
}


void Assembler::leave() {
  EnsureSpace ensure_space(this);
  emit(0xC9);
}


void Assembler::movb(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  if (!dst.is_byte_register()) {
    // Register is not one of al, bl, cl, dl.  Its encoding needs REX.
    emit_rex_32(dst, src);
  } else {
    emit_optional_rex_32(dst, src);
  }
  emit(0x8A);
  emit_operand(dst, src);
}


void Assembler::movb(Register dst, Immediate imm) {
  EnsureSpace ensure_space(this);
  if (!dst.is_byte_register()) {
    emit_rex_32(dst);
  }
  emit(0xB0 + dst.low_bits());
  emit(imm.value_);
}


void Assembler::movb(const Operand& dst, Register src) {
  EnsureSpace ensure_space(this);
  if (!src.is_byte_register()) {
    emit_rex_32(src, dst);
  } else {
    emit_optional_rex_32(src, dst);
  }
  emit(0x88);
  emit_operand(src, dst);
}


void Assembler::movw(const Operand& dst, Register src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(src, dst);
  emit(0x89);
  emit_operand(src, dst);
}


void Assembler::movl(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst, src);
  emit(0x8B);
  emit_operand(dst, src);
}


void Assembler::movl(Register dst, Register src) {
  EnsureSpace ensure_space(this);
  if (src.low_bits() == 4) {
    emit_optional_rex_32(src, dst);
    emit(0x89);
    emit_modrm(src, dst);
  } else {
    emit_optional_rex_32(dst, src);
    emit(0x8B);
    emit_modrm(dst, src);
  }
}


void Assembler::movl(const Operand& dst, Register src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(src, dst);
  emit(0x89);
  emit_operand(src, dst);
}


void Assembler::movl(const Operand& dst, Immediate value) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0xC7);
  emit_operand(0x0, dst);
  emit(value);
}


void Assembler::movl(Register dst, Immediate value) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0xB8 + dst.low_bits());
  emit(value);
}


void Assembler::movq(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst, src);
  emit(0x8B);
  emit_operand(dst, src);
}


void Assembler::movq(Register dst, Register src) {
  EnsureSpace ensure_space(this);
  if (src.low_bits() == 4) {
    emit_rex_64(src, dst);
    emit(0x89);
    emit_modrm(src, dst);
  } else {
    emit_rex_64(dst, src);
    emit(0x8B);
    emit_modrm(dst, src);
  }
}


void Assembler::movq(Register dst, Immediate value) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xC7);
  emit_modrm(0x0, dst);
  emit(value);  // Only 32-bit immediates are possible, not 8-bit immediates.
}


void Assembler::movq(const Operand& dst, Register src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(src, dst);
  emit(0x89);
  emit_operand(src, dst);
}


void Assembler::movq(Register dst, void* value, RelocInfo::Mode rmode) {
  // This method must not be used with heap object references. The stored
  // address is not GC safe. Use the handle version instead.
  ASSERT(rmode > RelocInfo::LAST_GCED_ENUM);
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xB8 | dst.low_bits());
  emitq(reinterpret_cast<uintptr_t>(value), rmode);
}


void Assembler::movq(Register dst, int64_t value, RelocInfo::Mode rmode) {
  // Non-relocatable values might not need a 64-bit representation.
  if (rmode == RelocInfo::NONE) {
    // Sadly, there is no zero or sign extending move for 8-bit immediates.
    if (is_int32(value)) {
      movq(dst, Immediate(static_cast<int32_t>(value)));
      return;
    } else if (is_uint32(value)) {
      movl(dst, Immediate(static_cast<int32_t>(value)));
      return;
    }
    // Value cannot be represented by 32 bits, so do a full 64 bit immediate
    // value.
  }
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xB8 | dst.low_bits());
  emitq(value, rmode);
}


void Assembler::movq(Register dst, ExternalReference ref) {
  int64_t value = reinterpret_cast<int64_t>(ref.address());
  movq(dst, value, RelocInfo::EXTERNAL_REFERENCE);
}


void Assembler::movq(const Operand& dst, Immediate value) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xC7);
  emit_operand(0, dst);
  emit(value);
}


// Loads the ip-relative location of the src label into the target location
// (as a 32-bit offset sign extended to 64-bit).
void Assembler::movl(const Operand& dst, Label* src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0xC7);
  emit_operand(0, dst);
  if (src->is_bound()) {
    int offset = src->pos() - pc_offset() - sizeof(int32_t);
    ASSERT(offset <= 0);
    emitl(offset);
  } else if (src->is_linked()) {
    emitl(src->pos());
    src->link_to(pc_offset() - sizeof(int32_t));
  } else {
    ASSERT(src->is_unused());
    int32_t current = pc_offset();
    emitl(current);
    src->link_to(current);
  }
}


void Assembler::movq(Register dst, Handle<Object> value, RelocInfo::Mode mode) {
  // If there is no relocation info, emit the value of the handle efficiently
  // (possibly using less that 8 bytes for the value).
  if (mode == RelocInfo::NONE) {
    // There is no possible reason to store a heap pointer without relocation
    // info, so it must be a smi.
    ASSERT(value->IsSmi());
    movq(dst, reinterpret_cast<int64_t>(*value), RelocInfo::NONE);
  } else {
    EnsureSpace ensure_space(this);
    ASSERT(value->IsHeapObject());
    ASSERT(!HEAP->InNewSpace(*value));
    emit_rex_64(dst);
    emit(0xB8 | dst.low_bits());
    emitq(reinterpret_cast<uintptr_t>(value.location()), mode);
  }
}


void Assembler::movsxbq(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst, src);
  emit(0x0F);
  emit(0xBE);
  emit_operand(dst, src);
}


void Assembler::movsxwq(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst, src);
  emit(0x0F);
  emit(0xBF);
  emit_operand(dst, src);
}


void Assembler::movsxlq(Register dst, Register src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst, src);
  emit(0x63);
  emit_modrm(dst, src);
}


void Assembler::movsxlq(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst, src);
  emit(0x63);
  emit_operand(dst, src);
}


void Assembler::movzxbq(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  // 32 bit operations zero the top 32 bits of 64 bit registers.  Therefore
  // there is no need to make this a 64 bit operation.
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0xB6);
  emit_operand(dst, src);
}


void Assembler::movzxbl(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0xB6);
  emit_operand(dst, src);
}


void Assembler::movzxwq(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0xB7);
  emit_operand(dst, src);
}


void Assembler::movzxwl(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0xB7);
  emit_operand(dst, src);
}


void Assembler::repmovsb() {
  EnsureSpace ensure_space(this);
  emit(0xF3);
  emit(0xA4);
}


void Assembler::repmovsw() {
  EnsureSpace ensure_space(this);
  emit(0x66);  // Operand size override.
  emit(0xF3);
  emit(0xA4);
}


void Assembler::repmovsl() {
  EnsureSpace ensure_space(this);
  emit(0xF3);
  emit(0xA5);
}


void Assembler::repmovsq() {
  EnsureSpace ensure_space(this);
  emit(0xF3);
  emit_rex_64();
  emit(0xA5);
}


void Assembler::mul(Register src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(src);
  emit(0xF7);
  emit_modrm(0x4, src);
}


void Assembler::neg(Register dst) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xF7);
  emit_modrm(0x3, dst);
}


void Assembler::negl(Register dst) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0xF7);
  emit_modrm(0x3, dst);
}


void Assembler::neg(const Operand& dst) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xF7);
  emit_operand(3, dst);
}


void Assembler::nop() {
  EnsureSpace ensure_space(this);
  emit(0x90);
}


void Assembler::not_(Register dst) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xF7);
  emit_modrm(0x2, dst);
}


void Assembler::not_(const Operand& dst) {
  EnsureSpace ensure_space(this);
  emit_rex_64(dst);
  emit(0xF7);
  emit_operand(2, dst);
}


void Assembler::notl(Register dst) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0xF7);
  emit_modrm(0x2, dst);
}


void Assembler::Nop(int n) {
  // The recommended muti-byte sequences of NOP instructions from the Intel 64
  // and IA-32 Architectures Software Developer's Manual.
  //
  // Length   Assembly                                Byte Sequence
  // 2 bytes  66 NOP                                  66 90H
  // 3 bytes  NOP DWORD ptr [EAX]                     0F 1F 00H
  // 4 bytes  NOP DWORD ptr [EAX + 00H]               0F 1F 40 00H
  // 5 bytes  NOP DWORD ptr [EAX + EAX*1 + 00H]       0F 1F 44 00 00H
  // 6 bytes  66 NOP DWORD ptr [EAX + EAX*1 + 00H]    66 0F 1F 44 00 00H
  // 7 bytes  NOP DWORD ptr [EAX + 00000000H]         0F 1F 80 00 00 00 00H
  // 8 bytes  NOP DWORD ptr [EAX + EAX*1 + 00000000H] 0F 1F 84 00 00 00 00 00H
  // 9 bytes  66 NOP DWORD ptr [EAX + EAX*1 +         66 0F 1F 84 00 00 00 00
  //          00000000H]                              00H

  EnsureSpace ensure_space(this);
  while (n > 0) {
    switch (n) {
      case 2:
        emit(0x66);
      case 1:
        emit(0x90);
        return;
      case 3:
        emit(0x0f);
        emit(0x1f);
        emit(0x00);
        return;
      case 4:
        emit(0x0f);
        emit(0x1f);
        emit(0x40);
        emit(0x00);
        return;
      case 6:
        emit(0x66);
      case 5:
        emit(0x0f);
        emit(0x1f);
        emit(0x44);
        emit(0x00);
        emit(0x00);
        return;
      case 7:
        emit(0x0f);
        emit(0x1f);
        emit(0x80);
        emit(0x00);
        emit(0x00);
        emit(0x00);
        emit(0x00);
        return;
      default:
      case 11:
        emit(0x66);
        n--;
      case 10:
        emit(0x66);
        n--;
      case 9:
        emit(0x66);
        n--;
      case 8:
        emit(0x0f);
        emit(0x1f);
        emit(0x84);
        emit(0x00);
        emit(0x00);
        emit(0x00);
        emit(0x00);
        emit(0x00);
        n -= 8;
    }
  }
}


void Assembler::pop(Register dst) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0x58 | dst.low_bits());
}


void Assembler::pop(const Operand& dst) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst);
  emit(0x8F);
  emit_operand(0, dst);
}


void Assembler::popfq() {
  EnsureSpace ensure_space(this);
  emit(0x9D);
}


void Assembler::push(Register src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(src);
  emit(0x50 | src.low_bits());
}


void Assembler::push(const Operand& src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(src);
  emit(0xFF);
  emit_operand(6, src);
}


void Assembler::push(Immediate value) {
  EnsureSpace ensure_space(this);
  if (is_int8(value.value_)) {
    emit(0x6A);
    emit(value.value_);  // Emit low byte of value.
  } else {
    emit(0x68);
    emitl(value.value_);
  }
}


void Assembler::push_imm32(int32_t imm32) {
  EnsureSpace ensure_space(this);
  emit(0x68);
  emitl(imm32);
}


void Assembler::pushfq() {
  EnsureSpace ensure_space(this);
  emit(0x9C);
}


void Assembler::rdtsc() {
  EnsureSpace ensure_space(this);
  emit(0x0F);
  emit(0x31);
}


void Assembler::ret(int imm16) {
  EnsureSpace ensure_space(this);
  ASSERT(is_uint16(imm16));
  if (imm16 == 0) {
    emit(0xC3);
  } else {
    emit(0xC2);
    emit(imm16 & 0xFF);
    emit((imm16 >> 8) & 0xFF);
  }
}


void Assembler::setcc(Condition cc, Register reg) {
  if (cc > last_condition) {
    movb(reg, Immediate(cc == always ? 1 : 0));
    return;
  }
  EnsureSpace ensure_space(this);
  ASSERT(is_uint4(cc));
  if (!reg.is_byte_register()) {  // Use x64 byte registers, where different.
    emit_rex_32(reg);
  }
  emit(0x0F);
  emit(0x90 | cc);
  emit_modrm(0x0, reg);
}


void Assembler::shld(Register dst, Register src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(src, dst);
  emit(0x0F);
  emit(0xA5);
  emit_modrm(src, dst);
}


void Assembler::shrd(Register dst, Register src) {
  EnsureSpace ensure_space(this);
  emit_rex_64(src, dst);
  emit(0x0F);
  emit(0xAD);
  emit_modrm(src, dst);
}


void Assembler::xchg(Register dst, Register src) {
  EnsureSpace ensure_space(this);
  if (src.is(rax) || dst.is(rax)) {  // Single-byte encoding
    Register other = src.is(rax) ? dst : src;
    emit_rex_64(other);
    emit(0x90 | other.low_bits());
  } else if (dst.low_bits() == 4) {
    emit_rex_64(dst, src);
    emit(0x87);
    emit_modrm(dst, src);
  } else {
    emit_rex_64(src, dst);
    emit(0x87);
    emit_modrm(src, dst);
  }
}


void Assembler::store_rax(void* dst, RelocInfo::Mode mode) {
  EnsureSpace ensure_space(this);
  emit(0x48);  // REX.W
  emit(0xA3);
  emitq(reinterpret_cast<uintptr_t>(dst), mode);
}


void Assembler::store_rax(ExternalReference ref) {
  store_rax(ref.address(), RelocInfo::EXTERNAL_REFERENCE);
}


void Assembler::testb(Register dst, Register src) {
  EnsureSpace ensure_space(this);
  if (src.low_bits() == 4) {
    emit_rex_32(src, dst);
    emit(0x84);
    emit_modrm(src, dst);
  } else {
    if (!dst.is_byte_register() || !src.is_byte_register()) {
      // Register is not one of al, bl, cl, dl.  Its encoding needs REX.
      emit_rex_32(dst, src);
    }
    emit(0x84);
    emit_modrm(dst, src);
  }
}


void Assembler::testb(Register reg, Immediate mask) {
  ASSERT(is_int8(mask.value_) || is_uint8(mask.value_));
  EnsureSpace ensure_space(this);
  if (reg.is(rax)) {
    emit(0xA8);
    emit(mask.value_);  // Low byte emitted.
  } else {
    if (!reg.is_byte_register()) {
      // Register is not one of al, bl, cl, dl.  Its encoding needs REX.
      emit_rex_32(reg);
    }
    emit(0xF6);
    emit_modrm(0x0, reg);
    emit(mask.value_);  // Low byte emitted.
  }
}


void Assembler::testb(const Operand& op, Immediate mask) {
  ASSERT(is_int8(mask.value_) || is_uint8(mask.value_));
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(rax, op);
  emit(0xF6);
  emit_operand(rax, op);  // Operation code 0
  emit(mask.value_);  // Low byte emitted.
}


void Assembler::testb(const Operand& op, Register reg) {
  EnsureSpace ensure_space(this);
  if (!reg.is_byte_register()) {
    // Register is not one of al, bl, cl, dl.  Its encoding needs REX.
    emit_rex_32(reg, op);
  } else {
    emit_optional_rex_32(reg, op);
  }
  emit(0x84);
  emit_operand(reg, op);
}


void Assembler::testl(Register dst, Register src) {
  EnsureSpace ensure_space(this);
  if (src.low_bits() == 4) {
    emit_optional_rex_32(src, dst);
    emit(0x85);
    emit_modrm(src, dst);
  } else {
    emit_optional_rex_32(dst, src);
    emit(0x85);
    emit_modrm(dst, src);
  }
}


void Assembler::testl(Register reg, Immediate mask) {
  // testl with a mask that fits in the low byte is exactly testb.
  if (is_uint8(mask.value_)) {
    testb(reg, mask);
    return;
  }
  EnsureSpace ensure_space(this);
  if (reg.is(rax)) {
    emit(0xA9);
    emit(mask);
  } else {
    emit_optional_rex_32(rax, reg);
    emit(0xF7);
    emit_modrm(0x0, reg);
    emit(mask);
  }
}


void Assembler::testl(const Operand& op, Immediate mask) {
  // testl with a mask that fits in the low byte is exactly testb.
  if (is_uint8(mask.value_)) {
    testb(op, mask);
    return;
  }
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(rax, op);
  emit(0xF7);
  emit_operand(rax, op);  // Operation code 0
  emit(mask);
}


void Assembler::testq(const Operand& op, Register reg) {
  EnsureSpace ensure_space(this);
  emit_rex_64(reg, op);
  emit(0x85);
  emit_operand(reg, op);
}


void Assembler::testq(Register dst, Register src) {
  EnsureSpace ensure_space(this);
  if (src.low_bits() == 4) {
    emit_rex_64(src, dst);
    emit(0x85);
    emit_modrm(src, dst);
  } else {
    emit_rex_64(dst, src);
    emit(0x85);
    emit_modrm(dst, src);
  }
}


void Assembler::testq(Register dst, Immediate mask) {
  EnsureSpace ensure_space(this);
  if (dst.is(rax)) {
    emit_rex_64();
    emit(0xA9);
    emit(mask);
  } else {
    emit_rex_64(dst);
    emit(0xF7);
    emit_modrm(0, dst);
    emit(mask);
  }
}


// FPU instructions.


void Assembler::fld(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xD9, 0xC0, i);
}


void Assembler::fld1() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xE8);
}


void Assembler::fldz() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xEE);
}


void Assembler::fldpi() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xEB);
}


void Assembler::fldln2() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xED);
}


void Assembler::fld_s(const Operand& adr) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xD9);
  emit_operand(0, adr);
}


void Assembler::fld_d(const Operand& adr) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xDD);
  emit_operand(0, adr);
}


void Assembler::fstp_s(const Operand& adr) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xD9);
  emit_operand(3, adr);
}


void Assembler::fstp_d(const Operand& adr) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xDD);
  emit_operand(3, adr);
}


void Assembler::fstp(int index) {
  ASSERT(is_uint3(index));
  EnsureSpace ensure_space(this);
  emit_farith(0xDD, 0xD8, index);
}


void Assembler::fild_s(const Operand& adr) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xDB);
  emit_operand(0, adr);
}


void Assembler::fild_d(const Operand& adr) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xDF);
  emit_operand(5, adr);
}


void Assembler::fistp_s(const Operand& adr) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xDB);
  emit_operand(3, adr);
}


void Assembler::fisttp_s(const Operand& adr) {
  ASSERT(CpuFeatures::IsEnabled(SSE3));
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xDB);
  emit_operand(1, adr);
}


void Assembler::fisttp_d(const Operand& adr) {
  ASSERT(CpuFeatures::IsEnabled(SSE3));
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xDD);
  emit_operand(1, adr);
}


void Assembler::fist_s(const Operand& adr) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xDB);
  emit_operand(2, adr);
}


void Assembler::fistp_d(const Operand& adr) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xDF);
  emit_operand(7, adr);
}


void Assembler::fabs() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xE1);
}


void Assembler::fchs() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xE0);
}


void Assembler::fcos() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xFF);
}


void Assembler::fsin() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xFE);
}


void Assembler::fptan() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xF2);
}


void Assembler::fyl2x() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xF1);
}


void Assembler::f2xm1() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xF0);
}


void Assembler::fscale() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xFD);
}


void Assembler::fninit() {
  EnsureSpace ensure_space(this);
  emit(0xDB);
  emit(0xE3);
}


void Assembler::fadd(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xDC, 0xC0, i);
}


void Assembler::fsub(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xDC, 0xE8, i);
}


void Assembler::fisub_s(const Operand& adr) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(adr);
  emit(0xDA);
  emit_operand(4, adr);
}


void Assembler::fmul(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xDC, 0xC8, i);
}


void Assembler::fdiv(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xDC, 0xF8, i);
}


void Assembler::faddp(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xDE, 0xC0, i);
}


void Assembler::fsubp(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xDE, 0xE8, i);
}


void Assembler::fsubrp(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xDE, 0xE0, i);
}


void Assembler::fmulp(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xDE, 0xC8, i);
}


void Assembler::fdivp(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xDE, 0xF8, i);
}


void Assembler::fprem() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xF8);
}


void Assembler::fprem1() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xF5);
}


void Assembler::fxch(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xD9, 0xC8, i);
}


void Assembler::fincstp() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xF7);
}


void Assembler::ffree(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xDD, 0xC0, i);
}


void Assembler::ftst() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xE4);
}


void Assembler::fucomp(int i) {
  EnsureSpace ensure_space(this);
  emit_farith(0xDD, 0xE8, i);
}


void Assembler::fucompp() {
  EnsureSpace ensure_space(this);
  emit(0xDA);
  emit(0xE9);
}


void Assembler::fucomi(int i) {
  EnsureSpace ensure_space(this);
  emit(0xDB);
  emit(0xE8 + i);
}


void Assembler::fucomip() {
  EnsureSpace ensure_space(this);
  emit(0xDF);
  emit(0xE9);
}


void Assembler::fcompp() {
  EnsureSpace ensure_space(this);
  emit(0xDE);
  emit(0xD9);
}


void Assembler::fnstsw_ax() {
  EnsureSpace ensure_space(this);
  emit(0xDF);
  emit(0xE0);
}


void Assembler::fwait() {
  EnsureSpace ensure_space(this);
  emit(0x9B);
}


void Assembler::frndint() {
  EnsureSpace ensure_space(this);
  emit(0xD9);
  emit(0xFC);
}


void Assembler::fnclex() {
  EnsureSpace ensure_space(this);
  emit(0xDB);
  emit(0xE2);
}


void Assembler::sahf() {
  // TODO(X64): Test for presence. Not all 64-bit intel CPU's have sahf
  // in 64-bit mode. Test CpuID.
  EnsureSpace ensure_space(this);
  emit(0x9E);
}


void Assembler::emit_farith(int b1, int b2, int i) {
  ASSERT(is_uint8(b1) && is_uint8(b2));  // wrong opcode
  ASSERT(is_uint3(i));  // illegal stack offset
  emit(b1);
  emit(b2 + i);
}

// SSE 2 operations.

void Assembler::movd(XMMRegister dst, Register src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x6E);
  emit_sse_operand(dst, src);
}


void Assembler::movd(Register dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(src, dst);
  emit(0x0F);
  emit(0x7E);
  emit_sse_operand(src, dst);
}


void Assembler::movq(XMMRegister dst, Register src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_rex_64(dst, src);
  emit(0x0F);
  emit(0x6E);
  emit_sse_operand(dst, src);
}


void Assembler::movq(Register dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_rex_64(src, dst);
  emit(0x0F);
  emit(0x7E);
  emit_sse_operand(src, dst);
}


void Assembler::movq(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  if (dst.low_bits() == 4) {
    // Avoid unnecessary SIB byte.
    emit(0xf3);
    emit_optional_rex_32(dst, src);
    emit(0x0F);
    emit(0x7e);
    emit_sse_operand(dst, src);
  } else {
    emit(0x66);
    emit_optional_rex_32(src, dst);
    emit(0x0F);
    emit(0xD6);
    emit_sse_operand(src, dst);
  }
}

void Assembler::movdqa(const Operand& dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_rex_64(src, dst);
  emit(0x0F);
  emit(0x7F);
  emit_sse_operand(src, dst);
}


void Assembler::movdqa(XMMRegister dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_rex_64(dst, src);
  emit(0x0F);
  emit(0x6F);
  emit_sse_operand(dst, src);
}


void Assembler::extractps(Register dst, XMMRegister src, byte imm8) {
  ASSERT(CpuFeatures::IsSupported(SSE4_1));
  ASSERT(is_uint8(imm8));
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x3A);
  emit(0x17);
  emit_sse_operand(dst, src);
  emit(imm8);
}


void Assembler::movsd(const Operand& dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);  // double
  emit_optional_rex_32(src, dst);
  emit(0x0F);
  emit(0x11);  // store
  emit_sse_operand(src, dst);
}


void Assembler::movsd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);  // double
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x10);  // load
  emit_sse_operand(dst, src);
}


void Assembler::movsd(XMMRegister dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);  // double
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x10);  // load
  emit_sse_operand(dst, src);
}


void Assembler::movaps(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  if (src.low_bits() == 4) {
    // Try to avoid an unnecessary SIB byte.
    emit_optional_rex_32(src, dst);
    emit(0x0F);
    emit(0x29);
    emit_sse_operand(src, dst);
  } else {
    emit_optional_rex_32(dst, src);
    emit(0x0F);
    emit(0x28);
    emit_sse_operand(dst, src);
  }
}


void Assembler::movapd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  if (src.low_bits() == 4) {
    // Try to avoid an unnecessary SIB byte.
    emit(0x66);
    emit_optional_rex_32(src, dst);
    emit(0x0F);
    emit(0x29);
    emit_sse_operand(src, dst);
  } else {
    emit(0x66);
    emit_optional_rex_32(dst, src);
    emit(0x0F);
    emit(0x28);
    emit_sse_operand(dst, src);
  }
}


void Assembler::movss(XMMRegister dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit(0xF3);  // single
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x10);  // load
  emit_sse_operand(dst, src);
}


void Assembler::movss(const Operand& src, XMMRegister dst) {
  EnsureSpace ensure_space(this);
  emit(0xF3);  // single
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x11);  // store
  emit_sse_operand(dst, src);
}


void Assembler::cvttss2si(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit(0xF3);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x2C);
  emit_operand(dst, src);
}


void Assembler::cvttss2si(Register dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF3);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x2C);
  emit_sse_operand(dst, src);
}


void Assembler::cvttsd2si(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x2C);
  emit_operand(dst, src);
}


void Assembler::cvttsd2si(Register dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x2C);
  emit_sse_operand(dst, src);
}


void Assembler::cvttsd2siq(Register dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_rex_64(dst, src);
  emit(0x0F);
  emit(0x2C);
  emit_sse_operand(dst, src);
}


void Assembler::cvtlsi2sd(XMMRegister dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x2A);
  emit_sse_operand(dst, src);
}


void Assembler::cvtlsi2sd(XMMRegister dst, Register src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x2A);
  emit_sse_operand(dst, src);
}


void Assembler::cvtlsi2ss(XMMRegister dst, Register src) {
  EnsureSpace ensure_space(this);
  emit(0xF3);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x2A);
  emit_sse_operand(dst, src);
}


void Assembler::cvtqsi2sd(XMMRegister dst, Register src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_rex_64(dst, src);
  emit(0x0F);
  emit(0x2A);
  emit_sse_operand(dst, src);
}


void Assembler::cvtss2sd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF3);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x5A);
  emit_sse_operand(dst, src);
}


void Assembler::cvtss2sd(XMMRegister dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit(0xF3);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x5A);
  emit_sse_operand(dst, src);
}


void Assembler::cvtsd2ss(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x5A);
  emit_sse_operand(dst, src);
}


void Assembler::cvtsd2si(Register dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x2D);
  emit_sse_operand(dst, src);
}


void Assembler::cvtsd2siq(Register dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_rex_64(dst, src);
  emit(0x0F);
  emit(0x2D);
  emit_sse_operand(dst, src);
}


void Assembler::addsd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x58);
  emit_sse_operand(dst, src);
}


void Assembler::mulsd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x59);
  emit_sse_operand(dst, src);
}


void Assembler::subsd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x5C);
  emit_sse_operand(dst, src);
}


void Assembler::divsd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x5E);
  emit_sse_operand(dst, src);
}


void Assembler::andpd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x54);
  emit_sse_operand(dst, src);
}


void Assembler::orpd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x56);
  emit_sse_operand(dst, src);
}


void Assembler::xorpd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x57);
  emit_sse_operand(dst, src);
}


void Assembler::xorps(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x57);
  emit_sse_operand(dst, src);
}


void Assembler::sqrtsd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0xF2);
  emit_optional_rex_32(dst, src);
  emit(0x0F);
  emit(0x51);
  emit_sse_operand(dst, src);
}


void Assembler::ucomisd(XMMRegister dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(dst, src);
  emit(0x0f);
  emit(0x2e);
  emit_sse_operand(dst, src);
}


void Assembler::ucomisd(XMMRegister dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(dst, src);
  emit(0x0f);
  emit(0x2e);
  emit_sse_operand(dst, src);
}


void Assembler::roundsd(XMMRegister dst, XMMRegister src,
                        Assembler::RoundingMode mode) {
  ASSERT(CpuFeatures::IsEnabled(SSE4_1));
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(dst, src);
  emit(0x0f);
  emit(0x3a);
  emit(0x0b);
  emit_sse_operand(dst, src);
  // Mask precision exeption.
  emit(static_cast<byte>(mode) | 0x8);
}


void Assembler::movmskpd(Register dst, XMMRegister src) {
  EnsureSpace ensure_space(this);
  emit(0x66);
  emit_optional_rex_32(dst, src);
  emit(0x0f);
  emit(0x50);
  emit_sse_operand(dst, src);
}


void Assembler::emit_sse_operand(XMMRegister reg, const Operand& adr) {
  Register ireg = { reg.code() };
  emit_operand(ireg, adr);
}


void Assembler::emit_sse_operand(XMMRegister dst, XMMRegister src) {
  emit(0xC0 | (dst.low_bits() << 3) | src.low_bits());
}

void Assembler::emit_sse_operand(XMMRegister dst, Register src) {
  emit(0xC0 | (dst.low_bits() << 3) | src.low_bits());
}

void Assembler::emit_sse_operand(Register dst, XMMRegister src) {
  emit(0xC0 | (dst.low_bits() << 3) | src.low_bits());
}


void Assembler::db(uint8_t data) {
  EnsureSpace ensure_space(this);
  emit(data);
}


void Assembler::dd(uint32_t data) {
  EnsureSpace ensure_space(this);
  emitl(data);
}


// Relocation information implementations.

void Assembler::RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data) {
  ASSERT(rmode != RelocInfo::NONE);
  // Don't record external references unless the heap will be serialized.
  if (rmode == RelocInfo::EXTERNAL_REFERENCE) {
#ifdef DEBUG
    if (!Serializer::enabled()) {
      Serializer::TooLateToEnableNow();
    }
#endif
    if (!Serializer::enabled() && !emit_debug_code()) {
      return;
    }
  }
  RelocInfo rinfo(pc_, rmode, data, NULL);
  reloc_info_writer.Write(&rinfo);
}

void Assembler::RecordJSReturn() {
  positions_recorder()->WriteRecordedPositions();
  EnsureSpace ensure_space(this);
  RecordRelocInfo(RelocInfo::JS_RETURN);
}


void Assembler::RecordDebugBreakSlot() {
  positions_recorder()->WriteRecordedPositions();
  EnsureSpace ensure_space(this);
  RecordRelocInfo(RelocInfo::DEBUG_BREAK_SLOT);
}


void Assembler::RecordComment(const char* msg, bool force) {
  if (FLAG_code_comments || force) {
    EnsureSpace ensure_space(this);
    RecordRelocInfo(RelocInfo::COMMENT, reinterpret_cast<intptr_t>(msg));
  }
}


const int RelocInfo::kApplyMask = RelocInfo::kCodeTargetMask |
                                  1 << RelocInfo::INTERNAL_REFERENCE;


bool RelocInfo::IsCodedSpecially() {
  // The deserializer needs to know whether a pointer is specially coded.  Being
  // specially coded on x64 means that it is a relative 32 bit address, as used
  // by branch instructions.
  return (1 << rmode_) & kApplyMask;
}

} }  // namespace v8::internal

#endif  // V8_TARGET_ARCH_X64

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