diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
new file mode 100644
index 0000000..e83bb92
--- /dev/null
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -0,0 +1,1192 @@
+// Copyright 2006-2009 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"
+
+#include "bootstrapper.h"
+#include "codegen-inl.h"
+#include "debug.h"
+#include "runtime.h"
+#include "serialize.h"
+
+namespace v8 {
+namespace internal {
+
+// -------------------------------------------------------------------------
+// MacroAssembler implementation.
+
+MacroAssembler::MacroAssembler(void* buffer, int size)
+    : Assembler(buffer, size),
+      unresolved_(0),
+      generating_stub_(false),
+      allow_stub_calls_(true),
+      code_object_(Heap::undefined_value()) {
+}
+
+
+static void RecordWriteHelper(MacroAssembler* masm,
+                              Register object,
+                              Register addr,
+                              Register scratch) {
+  Label fast;
+
+  // Compute the page start address from the heap object pointer, and reuse
+  // the 'object' register for it.
+  masm->and_(object, ~Page::kPageAlignmentMask);
+  Register page_start = object;
+
+  // Compute the bit addr in the remembered set/index of the pointer in the
+  // page. Reuse 'addr' as pointer_offset.
+  masm->sub(addr, Operand(page_start));
+  masm->shr(addr, kObjectAlignmentBits);
+  Register pointer_offset = addr;
+
+  // If the bit offset lies beyond the normal remembered set range, it is in
+  // the extra remembered set area of a large object.
+  masm->cmp(pointer_offset, Page::kPageSize / kPointerSize);
+  masm->j(less, &fast);
+
+  // Adjust 'page_start' so that addressing using 'pointer_offset' hits the
+  // extra remembered set after the large object.
+
+  // Find the length of the large object (FixedArray).
+  masm->mov(scratch, Operand(page_start, Page::kObjectStartOffset
+                                         + FixedArray::kLengthOffset));
+  Register array_length = scratch;
+
+  // Extra remembered set starts right after the large object (a FixedArray), at
+  //   page_start + kObjectStartOffset + objectSize
+  // where objectSize is FixedArray::kHeaderSize + kPointerSize * array_length.
+  // Add the delta between the end of the normal RSet and the start of the
+  // extra RSet to 'page_start', so that addressing the bit using
+  // 'pointer_offset' hits the extra RSet words.
+  masm->lea(page_start,
+            Operand(page_start, array_length, times_pointer_size,
+                    Page::kObjectStartOffset + FixedArray::kHeaderSize
+                        - Page::kRSetEndOffset));
+
+  // NOTE: For now, we use the bit-test-and-set (bts) x86 instruction
+  // to limit code size. We should probably evaluate this decision by
+  // measuring the performance of an equivalent implementation using
+  // "simpler" instructions
+  masm->bind(&fast);
+  masm->bts(Operand(page_start, Page::kRSetOffset), pointer_offset);
+}
+
+
+class RecordWriteStub : public CodeStub {
+ public:
+  RecordWriteStub(Register object, Register addr, Register scratch)
+      : object_(object), addr_(addr), scratch_(scratch) { }
+
+  void Generate(MacroAssembler* masm);
+
+ private:
+  Register object_;
+  Register addr_;
+  Register scratch_;
+
+#ifdef DEBUG
+  void Print() {
+    PrintF("RecordWriteStub (object reg %d), (addr reg %d), (scratch reg %d)\n",
+           object_.code(), addr_.code(), scratch_.code());
+  }
+#endif
+
+  // Minor key encoding in 12 bits of three registers (object, address and
+  // scratch) OOOOAAAASSSS.
+  class ScratchBits: public BitField<uint32_t, 0, 4> {};
+  class AddressBits: public BitField<uint32_t, 4, 4> {};
+  class ObjectBits: public BitField<uint32_t, 8, 4> {};
+
+  Major MajorKey() { return RecordWrite; }
+
+  int MinorKey() {
+    // Encode the registers.
+    return ObjectBits::encode(object_.code()) |
+           AddressBits::encode(addr_.code()) |
+           ScratchBits::encode(scratch_.code());
+  }
+};
+
+
+void RecordWriteStub::Generate(MacroAssembler* masm) {
+  RecordWriteHelper(masm, object_, addr_, scratch_);
+  masm->ret(0);
+}
+
+
+// Set the remembered set bit for [object+offset].
+// object is the object being stored into, value is the object being stored.
+// If offset is zero, then the scratch register contains the array index into
+// the elements array represented as a Smi.
+// All registers are clobbered by the operation.
+void MacroAssembler::RecordWrite(Register object, int offset,
+                                 Register value, Register scratch) {
+  // First, check if a remembered set write is even needed. The tests below
+  // catch stores of Smis and stores into young gen (which does not have space
+  // for the remembered set bits.
+  Label done;
+
+  // Skip barrier if writing a smi.
+  ASSERT_EQ(0, kSmiTag);
+  test(value, Immediate(kSmiTagMask));
+  j(zero, &done);
+
+  if (Serializer::enabled()) {
+    // Can't do arithmetic on external references if it might get serialized.
+    mov(value, Operand(object));
+    and_(value, Heap::NewSpaceMask());
+    cmp(Operand(value), Immediate(ExternalReference::new_space_start()));
+    j(equal, &done);
+  } else {
+    int32_t new_space_start = reinterpret_cast<int32_t>(
+        ExternalReference::new_space_start().address());
+    lea(value, Operand(object, -new_space_start));
+    and_(value, Heap::NewSpaceMask());
+    j(equal, &done);
+  }
+
+  if ((offset > 0) && (offset < Page::kMaxHeapObjectSize)) {
+    // Compute the bit offset in the remembered set, leave it in 'value'.
+    lea(value, Operand(object, offset));
+    and_(value, Page::kPageAlignmentMask);
+    shr(value, kPointerSizeLog2);
+
+    // Compute the page address from the heap object pointer, leave it in
+    // 'object'.
+    and_(object, ~Page::kPageAlignmentMask);
+
+    // NOTE: For now, we use the bit-test-and-set (bts) x86 instruction
+    // to limit code size. We should probably evaluate this decision by
+    // measuring the performance of an equivalent implementation using
+    // "simpler" instructions
+    bts(Operand(object, Page::kRSetOffset), value);
+  } else {
+    Register dst = scratch;
+    if (offset != 0) {
+      lea(dst, Operand(object, offset));
+    } else {
+      // array access: calculate the destination address in the same manner as
+      // KeyedStoreIC::GenerateGeneric.  Multiply a smi by 2 to get an offset
+      // into an array of words.
+      ASSERT_EQ(1, kSmiTagSize);
+      ASSERT_EQ(0, kSmiTag);
+      lea(dst, Operand(object, dst, times_half_pointer_size,
+                       FixedArray::kHeaderSize - kHeapObjectTag));
+    }
+    // If we are already generating a shared stub, not inlining the
+    // record write code isn't going to save us any memory.
+    if (generating_stub()) {
+      RecordWriteHelper(this, object, dst, value);
+    } else {
+      RecordWriteStub stub(object, dst, value);
+      CallStub(&stub);
+    }
+  }
+
+  bind(&done);
+}
+
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+void MacroAssembler::SaveRegistersToMemory(RegList regs) {
+  ASSERT((regs & ~kJSCallerSaved) == 0);
+  // Copy the content of registers to memory location.
+  for (int i = 0; i < kNumJSCallerSaved; i++) {
+    int r = JSCallerSavedCode(i);
+    if ((regs & (1 << r)) != 0) {
+      Register reg = { r };
+      ExternalReference reg_addr =
+          ExternalReference(Debug_Address::Register(i));
+      mov(Operand::StaticVariable(reg_addr), reg);
+    }
+  }
+}
+
+
+void MacroAssembler::RestoreRegistersFromMemory(RegList regs) {
+  ASSERT((regs & ~kJSCallerSaved) == 0);
+  // Copy the content of memory location to registers.
+  for (int i = kNumJSCallerSaved; --i >= 0;) {
+    int r = JSCallerSavedCode(i);
+    if ((regs & (1 << r)) != 0) {
+      Register reg = { r };
+      ExternalReference reg_addr =
+          ExternalReference(Debug_Address::Register(i));
+      mov(reg, Operand::StaticVariable(reg_addr));
+    }
+  }
+}
+
+
+void MacroAssembler::PushRegistersFromMemory(RegList regs) {
+  ASSERT((regs & ~kJSCallerSaved) == 0);
+  // Push the content of the memory location to the stack.
+  for (int i = 0; i < kNumJSCallerSaved; i++) {
+    int r = JSCallerSavedCode(i);
+    if ((regs & (1 << r)) != 0) {
+      ExternalReference reg_addr =
+          ExternalReference(Debug_Address::Register(i));
+      push(Operand::StaticVariable(reg_addr));
+    }
+  }
+}
+
+
+void MacroAssembler::PopRegistersToMemory(RegList regs) {
+  ASSERT((regs & ~kJSCallerSaved) == 0);
+  // Pop the content from the stack to the memory location.
+  for (int i = kNumJSCallerSaved; --i >= 0;) {
+    int r = JSCallerSavedCode(i);
+    if ((regs & (1 << r)) != 0) {
+      ExternalReference reg_addr =
+          ExternalReference(Debug_Address::Register(i));
+      pop(Operand::StaticVariable(reg_addr));
+    }
+  }
+}
+
+
+void MacroAssembler::CopyRegistersFromStackToMemory(Register base,
+                                                    Register scratch,
+                                                    RegList regs) {
+  ASSERT((regs & ~kJSCallerSaved) == 0);
+  // Copy the content of the stack to the memory location and adjust base.
+  for (int i = kNumJSCallerSaved; --i >= 0;) {
+    int r = JSCallerSavedCode(i);
+    if ((regs & (1 << r)) != 0) {
+      mov(scratch, Operand(base, 0));
+      ExternalReference reg_addr =
+          ExternalReference(Debug_Address::Register(i));
+      mov(Operand::StaticVariable(reg_addr), scratch);
+      lea(base, Operand(base, kPointerSize));
+    }
+  }
+}
+#endif
+
+void MacroAssembler::Set(Register dst, const Immediate& x) {
+  if (x.is_zero()) {
+    xor_(dst, Operand(dst));  // shorter than mov
+  } else {
+    mov(dst, x);
+  }
+}
+
+
+void MacroAssembler::Set(const Operand& dst, const Immediate& x) {
+  mov(dst, x);
+}
+
+
+void MacroAssembler::CmpObjectType(Register heap_object,
+                                   InstanceType type,
+                                   Register map) {
+  mov(map, FieldOperand(heap_object, HeapObject::kMapOffset));
+  CmpInstanceType(map, type);
+}
+
+
+void MacroAssembler::CmpInstanceType(Register map, InstanceType type) {
+  cmpb(FieldOperand(map, Map::kInstanceTypeOffset),
+       static_cast<int8_t>(type));
+}
+
+
+void MacroAssembler::FCmp() {
+  fucompp();
+  push(eax);
+  fnstsw_ax();
+  sahf();
+  pop(eax);
+}
+
+
+void MacroAssembler::EnterFrame(StackFrame::Type type) {
+  push(ebp);
+  mov(ebp, Operand(esp));
+  push(esi);
+  push(Immediate(Smi::FromInt(type)));
+  push(Immediate(CodeObject()));
+  if (FLAG_debug_code) {
+    cmp(Operand(esp, 0), Immediate(Factory::undefined_value()));
+    Check(not_equal, "code object not properly patched");
+  }
+}
+
+
+void MacroAssembler::LeaveFrame(StackFrame::Type type) {
+  if (FLAG_debug_code) {
+    cmp(Operand(ebp, StandardFrameConstants::kMarkerOffset),
+        Immediate(Smi::FromInt(type)));
+    Check(equal, "stack frame types must match");
+  }
+  leave();
+}
+
+
+void MacroAssembler::EnterExitFrame(StackFrame::Type type) {
+  ASSERT(type == StackFrame::EXIT || type == StackFrame::EXIT_DEBUG);
+
+  // Setup the frame structure on the stack.
+  ASSERT(ExitFrameConstants::kCallerSPDisplacement == +2 * kPointerSize);
+  ASSERT(ExitFrameConstants::kCallerPCOffset == +1 * kPointerSize);
+  ASSERT(ExitFrameConstants::kCallerFPOffset ==  0 * kPointerSize);
+  push(ebp);
+  mov(ebp, Operand(esp));
+
+  // Reserve room for entry stack pointer and push the debug marker.
+  ASSERT(ExitFrameConstants::kSPOffset  == -1 * kPointerSize);
+  push(Immediate(0));  // saved entry sp, patched before call
+  push(Immediate(type == StackFrame::EXIT_DEBUG ? 1 : 0));
+
+  // Save the frame pointer and the context in top.
+  ExternalReference c_entry_fp_address(Top::k_c_entry_fp_address);
+  ExternalReference context_address(Top::k_context_address);
+  mov(Operand::StaticVariable(c_entry_fp_address), ebp);
+  mov(Operand::StaticVariable(context_address), esi);
+
+  // Setup argc and argv in callee-saved registers.
+  int offset = StandardFrameConstants::kCallerSPOffset - kPointerSize;
+  mov(edi, Operand(eax));
+  lea(esi, Operand(ebp, eax, times_4, offset));
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  // Save the state of all registers to the stack from the memory
+  // location. This is needed to allow nested break points.
+  if (type == StackFrame::EXIT_DEBUG) {
+    // TODO(1243899): This should be symmetric to
+    // CopyRegistersFromStackToMemory() but it isn't! esp is assumed
+    // correct here, but computed for the other call. Very error
+    // prone! FIX THIS.  Actually there are deeper problems with
+    // register saving than this asymmetry (see the bug report
+    // associated with this issue).
+    PushRegistersFromMemory(kJSCallerSaved);
+  }
+#endif
+
+  // Reserve space for two arguments: argc and argv.
+  sub(Operand(esp), Immediate(2 * kPointerSize));
+
+  // Get the required frame alignment for the OS.
+  static const int kFrameAlignment = OS::ActivationFrameAlignment();
+  if (kFrameAlignment > 0) {
+    ASSERT(IsPowerOf2(kFrameAlignment));
+    and_(esp, -kFrameAlignment);
+  }
+
+  // Patch the saved entry sp.
+  mov(Operand(ebp, ExitFrameConstants::kSPOffset), esp);
+}
+
+
+void MacroAssembler::LeaveExitFrame(StackFrame::Type type) {
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  // Restore the memory copy of the registers by digging them out from
+  // the stack. This is needed to allow nested break points.
+  if (type == StackFrame::EXIT_DEBUG) {
+    // It's okay to clobber register ebx below because we don't need
+    // the function pointer after this.
+    const int kCallerSavedSize = kNumJSCallerSaved * kPointerSize;
+    int kOffset = ExitFrameConstants::kDebugMarkOffset - kCallerSavedSize;
+    lea(ebx, Operand(ebp, kOffset));
+    CopyRegistersFromStackToMemory(ebx, ecx, kJSCallerSaved);
+  }
+#endif
+
+  // Get the return address from the stack and restore the frame pointer.
+  mov(ecx, Operand(ebp, 1 * kPointerSize));
+  mov(ebp, Operand(ebp, 0 * kPointerSize));
+
+  // Pop the arguments and the receiver from the caller stack.
+  lea(esp, Operand(esi, 1 * kPointerSize));
+
+  // Restore current context from top and clear it in debug mode.
+  ExternalReference context_address(Top::k_context_address);
+  mov(esi, Operand::StaticVariable(context_address));
+#ifdef DEBUG
+  mov(Operand::StaticVariable(context_address), Immediate(0));
+#endif
+
+  // Push the return address to get ready to return.
+  push(ecx);
+
+  // Clear the top frame.
+  ExternalReference c_entry_fp_address(Top::k_c_entry_fp_address);
+  mov(Operand::StaticVariable(c_entry_fp_address), Immediate(0));
+}
+
+
+void MacroAssembler::PushTryHandler(CodeLocation try_location,
+                                    HandlerType type) {
+  // Adjust this code if not the case.
+  ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
+  // The pc (return address) is already on TOS.
+  if (try_location == IN_JAVASCRIPT) {
+    if (type == TRY_CATCH_HANDLER) {
+      push(Immediate(StackHandler::TRY_CATCH));
+    } else {
+      push(Immediate(StackHandler::TRY_FINALLY));
+    }
+    push(ebp);
+  } else {
+    ASSERT(try_location == IN_JS_ENTRY);
+    // The frame pointer does not point to a JS frame so we save NULL
+    // for ebp. We expect the code throwing an exception to check ebp
+    // before dereferencing it to restore the context.
+    push(Immediate(StackHandler::ENTRY));
+    push(Immediate(0));  // NULL frame pointer.
+  }
+  // Save the current handler as the next handler.
+  push(Operand::StaticVariable(ExternalReference(Top::k_handler_address)));
+  // Link this handler as the new current one.
+  mov(Operand::StaticVariable(ExternalReference(Top::k_handler_address)), esp);
+}
+
+
+Register MacroAssembler::CheckMaps(JSObject* object, Register object_reg,
+                                   JSObject* holder, Register holder_reg,
+                                   Register scratch,
+                                   Label* miss) {
+  // Make sure there's no overlap between scratch and the other
+  // registers.
+  ASSERT(!scratch.is(object_reg) && !scratch.is(holder_reg));
+
+  // Keep track of the current object in register reg.
+  Register reg = object_reg;
+  int depth = 1;
+
+  // Check the maps in the prototype chain.
+  // Traverse the prototype chain from the object and do map checks.
+  while (object != holder) {
+    depth++;
+
+    // Only global objects and objects that do not require access
+    // checks are allowed in stubs.
+    ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
+
+    JSObject* prototype = JSObject::cast(object->GetPrototype());
+    if (Heap::InNewSpace(prototype)) {
+      // Get the map of the current object.
+      mov(scratch, FieldOperand(reg, HeapObject::kMapOffset));
+      cmp(Operand(scratch), Immediate(Handle<Map>(object->map())));
+      // Branch on the result of the map check.
+      j(not_equal, miss, not_taken);
+      // Check access rights to the global object.  This has to happen
+      // after the map check so that we know that the object is
+      // actually a global object.
+      if (object->IsJSGlobalProxy()) {
+        CheckAccessGlobalProxy(reg, scratch, miss);
+
+        // Restore scratch register to be the map of the object.
+        // We load the prototype from the map in the scratch register.
+        mov(scratch, FieldOperand(reg, HeapObject::kMapOffset));
+      }
+      // The prototype is in new space; we cannot store a reference
+      // to it in the code. Load it from the map.
+      reg = holder_reg;  // from now the object is in holder_reg
+      mov(reg, FieldOperand(scratch, Map::kPrototypeOffset));
+
+    } else {
+      // Check the map of the current object.
+      cmp(FieldOperand(reg, HeapObject::kMapOffset),
+          Immediate(Handle<Map>(object->map())));
+      // Branch on the result of the map check.
+      j(not_equal, miss, not_taken);
+      // Check access rights to the global object.  This has to happen
+      // after the map check so that we know that the object is
+      // actually a global object.
+      if (object->IsJSGlobalProxy()) {
+        CheckAccessGlobalProxy(reg, scratch, miss);
+      }
+      // The prototype is in old space; load it directly.
+      reg = holder_reg;  // from now the object is in holder_reg
+      mov(reg, Handle<JSObject>(prototype));
+    }
+
+    // Go to the next object in the prototype chain.
+    object = prototype;
+  }
+
+  // Check the holder map.
+  cmp(FieldOperand(reg, HeapObject::kMapOffset),
+      Immediate(Handle<Map>(holder->map())));
+  j(not_equal, miss, not_taken);
+
+  // Log the check depth.
+  LOG(IntEvent("check-maps-depth", depth));
+
+  // Perform security check for access to the global object and return
+  // the holder register.
+  ASSERT(object == holder);
+  ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
+  if (object->IsJSGlobalProxy()) {
+    CheckAccessGlobalProxy(reg, scratch, miss);
+  }
+  return reg;
+}
+
+
+void MacroAssembler::CheckAccessGlobalProxy(Register holder_reg,
+                                            Register scratch,
+                                            Label* miss) {
+  Label same_contexts;
+
+  ASSERT(!holder_reg.is(scratch));
+
+  // Load current lexical context from the stack frame.
+  mov(scratch, Operand(ebp, StandardFrameConstants::kContextOffset));
+
+  // When generating debug code, make sure the lexical context is set.
+  if (FLAG_debug_code) {
+    cmp(Operand(scratch), Immediate(0));
+    Check(not_equal, "we should not have an empty lexical context");
+  }
+  // Load the global context of the current context.
+  int offset = Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize;
+  mov(scratch, FieldOperand(scratch, offset));
+  mov(scratch, FieldOperand(scratch, GlobalObject::kGlobalContextOffset));
+
+  // Check the context is a global context.
+  if (FLAG_debug_code) {
+    push(scratch);
+    // Read the first word and compare to global_context_map.
+    mov(scratch, FieldOperand(scratch, HeapObject::kMapOffset));
+    cmp(scratch, Factory::global_context_map());
+    Check(equal, "JSGlobalObject::global_context should be a global context.");
+    pop(scratch);
+  }
+
+  // Check if both contexts are the same.
+  cmp(scratch, FieldOperand(holder_reg, JSGlobalProxy::kContextOffset));
+  j(equal, &same_contexts, taken);
+
+  // Compare security tokens, save holder_reg on the stack so we can use it
+  // as a temporary register.
+  //
+  // TODO(119): avoid push(holder_reg)/pop(holder_reg)
+  push(holder_reg);
+  // Check that the security token in the calling global object is
+  // compatible with the security token in the receiving global
+  // object.
+  mov(holder_reg, FieldOperand(holder_reg, JSGlobalProxy::kContextOffset));
+
+  // Check the context is a global context.
+  if (FLAG_debug_code) {
+    cmp(holder_reg, Factory::null_value());
+    Check(not_equal, "JSGlobalProxy::context() should not be null.");
+
+    push(holder_reg);
+    // Read the first word and compare to global_context_map(),
+    mov(holder_reg, FieldOperand(holder_reg, HeapObject::kMapOffset));
+    cmp(holder_reg, Factory::global_context_map());
+    Check(equal, "JSGlobalObject::global_context should be a global context.");
+    pop(holder_reg);
+  }
+
+  int token_offset = Context::kHeaderSize +
+                     Context::SECURITY_TOKEN_INDEX * kPointerSize;
+  mov(scratch, FieldOperand(scratch, token_offset));
+  cmp(scratch, FieldOperand(holder_reg, token_offset));
+  pop(holder_reg);
+  j(not_equal, miss, not_taken);
+
+  bind(&same_contexts);
+}
+
+
+void MacroAssembler::LoadAllocationTopHelper(Register result,
+                                             Register result_end,
+                                             Register scratch,
+                                             AllocationFlags flags) {
+  ExternalReference new_space_allocation_top =
+      ExternalReference::new_space_allocation_top_address();
+
+  // Just return if allocation top is already known.
+  if ((flags & RESULT_CONTAINS_TOP) != 0) {
+    // No use of scratch if allocation top is provided.
+    ASSERT(scratch.is(no_reg));
+#ifdef DEBUG
+    // Assert that result actually contains top on entry.
+    cmp(result, Operand::StaticVariable(new_space_allocation_top));
+    Check(equal, "Unexpected allocation top");
+#endif
+    return;
+  }
+
+  // Move address of new object to result. Use scratch register if available.
+  if (scratch.is(no_reg)) {
+    mov(result, Operand::StaticVariable(new_space_allocation_top));
+  } else {
+    ASSERT(!scratch.is(result_end));
+    mov(Operand(scratch), Immediate(new_space_allocation_top));
+    mov(result, Operand(scratch, 0));
+  }
+}
+
+
+void MacroAssembler::UpdateAllocationTopHelper(Register result_end,
+                                               Register scratch) {
+  ExternalReference new_space_allocation_top =
+      ExternalReference::new_space_allocation_top_address();
+
+  // Update new top. Use scratch if available.
+  if (scratch.is(no_reg)) {
+    mov(Operand::StaticVariable(new_space_allocation_top), result_end);
+  } else {
+    mov(Operand(scratch, 0), result_end);
+  }
+}
+
+
+void MacroAssembler::AllocateInNewSpace(int object_size,
+                                        Register result,
+                                        Register result_end,
+                                        Register scratch,
+                                        Label* gc_required,
+                                        AllocationFlags flags) {
+  ASSERT(!result.is(result_end));
+
+  // Load address of new object into result.
+  LoadAllocationTopHelper(result, result_end, scratch, flags);
+
+  // Calculate new top and bail out if new space is exhausted.
+  ExternalReference new_space_allocation_limit =
+      ExternalReference::new_space_allocation_limit_address();
+  lea(result_end, Operand(result, object_size));
+  cmp(result_end, Operand::StaticVariable(new_space_allocation_limit));
+  j(above, gc_required, not_taken);
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
+
+  // Tag result if requested.
+  if ((flags & TAG_OBJECT) != 0) {
+    or_(Operand(result), Immediate(kHeapObjectTag));
+  }
+}
+
+
+void MacroAssembler::AllocateInNewSpace(int header_size,
+                                        ScaleFactor element_size,
+                                        Register element_count,
+                                        Register result,
+                                        Register result_end,
+                                        Register scratch,
+                                        Label* gc_required,
+                                        AllocationFlags flags) {
+  ASSERT(!result.is(result_end));
+
+  // Load address of new object into result.
+  LoadAllocationTopHelper(result, result_end, scratch, flags);
+
+  // Calculate new top and bail out if new space is exhausted.
+  ExternalReference new_space_allocation_limit =
+      ExternalReference::new_space_allocation_limit_address();
+  lea(result_end, Operand(result, element_count, element_size, header_size));
+  cmp(result_end, Operand::StaticVariable(new_space_allocation_limit));
+  j(above, gc_required);
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
+
+  // Tag result if requested.
+  if ((flags & TAG_OBJECT) != 0) {
+    or_(Operand(result), Immediate(kHeapObjectTag));
+  }
+}
+
+
+void MacroAssembler::AllocateInNewSpace(Register object_size,
+                                        Register result,
+                                        Register result_end,
+                                        Register scratch,
+                                        Label* gc_required,
+                                        AllocationFlags flags) {
+  ASSERT(!result.is(result_end));
+
+  // Load address of new object into result.
+  LoadAllocationTopHelper(result, result_end, scratch, flags);
+
+  // Calculate new top and bail out if new space is exhausted.
+  ExternalReference new_space_allocation_limit =
+      ExternalReference::new_space_allocation_limit_address();
+  if (!object_size.is(result_end)) {
+    mov(result_end, object_size);
+  }
+  add(result_end, Operand(result));
+  cmp(result_end, Operand::StaticVariable(new_space_allocation_limit));
+  j(above, gc_required, not_taken);
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
+
+  // Tag result if requested.
+  if ((flags & TAG_OBJECT) != 0) {
+    or_(Operand(result), Immediate(kHeapObjectTag));
+  }
+}
+
+
+void MacroAssembler::UndoAllocationInNewSpace(Register object) {
+  ExternalReference new_space_allocation_top =
+      ExternalReference::new_space_allocation_top_address();
+
+  // Make sure the object has no tag before resetting top.
+  and_(Operand(object), Immediate(~kHeapObjectTagMask));
+#ifdef DEBUG
+  cmp(object, Operand::StaticVariable(new_space_allocation_top));
+  Check(below, "Undo allocation of non allocated memory");
+#endif
+  mov(Operand::StaticVariable(new_space_allocation_top), object);
+}
+
+
+void MacroAssembler::NegativeZeroTest(CodeGenerator* cgen,
+                                      Register result,
+                                      Register op,
+                                      JumpTarget* then_target) {
+  JumpTarget ok;
+  test(result, Operand(result));
+  ok.Branch(not_zero, taken);
+  test(op, Operand(op));
+  then_target->Branch(sign, not_taken);
+  ok.Bind();
+}
+
+
+void MacroAssembler::NegativeZeroTest(Register result,
+                                      Register op,
+                                      Label* then_label) {
+  Label ok;
+  test(result, Operand(result));
+  j(not_zero, &ok, taken);
+  test(op, Operand(op));
+  j(sign, then_label, not_taken);
+  bind(&ok);
+}
+
+
+void MacroAssembler::NegativeZeroTest(Register result,
+                                      Register op1,
+                                      Register op2,
+                                      Register scratch,
+                                      Label* then_label) {
+  Label ok;
+  test(result, Operand(result));
+  j(not_zero, &ok, taken);
+  mov(scratch, Operand(op1));
+  or_(scratch, Operand(op2));
+  j(sign, then_label, not_taken);
+  bind(&ok);
+}
+
+
+void MacroAssembler::TryGetFunctionPrototype(Register function,
+                                             Register result,
+                                             Register scratch,
+                                             Label* miss) {
+  // Check that the receiver isn't a smi.
+  test(function, Immediate(kSmiTagMask));
+  j(zero, miss, not_taken);
+
+  // Check that the function really is a function.
+  CmpObjectType(function, JS_FUNCTION_TYPE, result);
+  j(not_equal, miss, not_taken);
+
+  // Make sure that the function has an instance prototype.
+  Label non_instance;
+  movzx_b(scratch, FieldOperand(result, Map::kBitFieldOffset));
+  test(scratch, Immediate(1 << Map::kHasNonInstancePrototype));
+  j(not_zero, &non_instance, not_taken);
+
+  // Get the prototype or initial map from the function.
+  mov(result,
+      FieldOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
+
+  // If the prototype or initial map is the hole, don't return it and
+  // simply miss the cache instead. This will allow us to allocate a
+  // prototype object on-demand in the runtime system.
+  cmp(Operand(result), Immediate(Factory::the_hole_value()));
+  j(equal, miss, not_taken);
+
+  // If the function does not have an initial map, we're done.
+  Label done;
+  CmpObjectType(result, MAP_TYPE, scratch);
+  j(not_equal, &done);
+
+  // Get the prototype from the initial map.
+  mov(result, FieldOperand(result, Map::kPrototypeOffset));
+  jmp(&done);
+
+  // Non-instance prototype: Fetch prototype from constructor field
+  // in initial map.
+  bind(&non_instance);
+  mov(result, FieldOperand(result, Map::kConstructorOffset));
+
+  // All done.
+  bind(&done);
+}
+
+
+void MacroAssembler::CallStub(CodeStub* stub) {
+  ASSERT(allow_stub_calls());  // calls are not allowed in some stubs
+  call(stub->GetCode(), RelocInfo::CODE_TARGET);
+}
+
+
+void MacroAssembler::StubReturn(int argc) {
+  ASSERT(argc >= 1 && generating_stub());
+  ret((argc - 1) * kPointerSize);
+}
+
+
+void MacroAssembler::IllegalOperation(int num_arguments) {
+  if (num_arguments > 0) {
+    add(Operand(esp), Immediate(num_arguments * kPointerSize));
+  }
+  mov(eax, Immediate(Factory::undefined_value()));
+}
+
+
+void MacroAssembler::CallRuntime(Runtime::FunctionId id, int num_arguments) {
+  CallRuntime(Runtime::FunctionForId(id), num_arguments);
+}
+
+
+void MacroAssembler::CallRuntime(Runtime::Function* f, int num_arguments) {
+  // If the expected number of arguments of the runtime function is
+  // constant, we check that the actual number of arguments match the
+  // expectation.
+  if (f->nargs >= 0 && f->nargs != num_arguments) {
+    IllegalOperation(num_arguments);
+    return;
+  }
+
+  Runtime::FunctionId function_id =
+      static_cast<Runtime::FunctionId>(f->stub_id);
+  RuntimeStub stub(function_id, num_arguments);
+  CallStub(&stub);
+}
+
+
+void MacroAssembler::TailCallRuntime(const ExternalReference& ext,
+                                     int num_arguments,
+                                     int result_size) {
+  // TODO(1236192): Most runtime routines don't need the number of
+  // arguments passed in because it is constant. At some point we
+  // should remove this need and make the runtime routine entry code
+  // smarter.
+  Set(eax, Immediate(num_arguments));
+  JumpToRuntime(ext);
+}
+
+
+void MacroAssembler::JumpToRuntime(const ExternalReference& ext) {
+  // Set the entry point and jump to the C entry runtime stub.
+  mov(ebx, Immediate(ext));
+  CEntryStub ces(1);
+  jmp(ces.GetCode(), RelocInfo::CODE_TARGET);
+}
+
+
+void MacroAssembler::InvokePrologue(const ParameterCount& expected,
+                                    const ParameterCount& actual,
+                                    Handle<Code> code_constant,
+                                    const Operand& code_operand,
+                                    Label* done,
+                                    InvokeFlag flag) {
+  bool definitely_matches = false;
+  Label invoke;
+  if (expected.is_immediate()) {
+    ASSERT(actual.is_immediate());
+    if (expected.immediate() == actual.immediate()) {
+      definitely_matches = true;
+    } else {
+      mov(eax, actual.immediate());
+      const int sentinel = SharedFunctionInfo::kDontAdaptArgumentsSentinel;
+      if (expected.immediate() == sentinel) {
+        // Don't worry about adapting arguments for builtins that
+        // don't want that done. Skip adaption code by making it look
+        // like we have a match between expected and actual number of
+        // arguments.
+        definitely_matches = true;
+      } else {
+        mov(ebx, expected.immediate());
+      }
+    }
+  } else {
+    if (actual.is_immediate()) {
+      // Expected is in register, actual is immediate. This is the
+      // case when we invoke function values without going through the
+      // IC mechanism.
+      cmp(expected.reg(), actual.immediate());
+      j(equal, &invoke);
+      ASSERT(expected.reg().is(ebx));
+      mov(eax, actual.immediate());
+    } else if (!expected.reg().is(actual.reg())) {
+      // Both expected and actual are in (different) registers. This
+      // is the case when we invoke functions using call and apply.
+      cmp(expected.reg(), Operand(actual.reg()));
+      j(equal, &invoke);
+      ASSERT(actual.reg().is(eax));
+      ASSERT(expected.reg().is(ebx));
+    }
+  }
+
+  if (!definitely_matches) {
+    Handle<Code> adaptor =
+        Handle<Code>(Builtins::builtin(Builtins::ArgumentsAdaptorTrampoline));
+    if (!code_constant.is_null()) {
+      mov(edx, Immediate(code_constant));
+      add(Operand(edx), Immediate(Code::kHeaderSize - kHeapObjectTag));
+    } else if (!code_operand.is_reg(edx)) {
+      mov(edx, code_operand);
+    }
+
+    if (flag == CALL_FUNCTION) {
+      call(adaptor, RelocInfo::CODE_TARGET);
+      jmp(done);
+    } else {
+      jmp(adaptor, RelocInfo::CODE_TARGET);
+    }
+    bind(&invoke);
+  }
+}
+
+
+void MacroAssembler::InvokeCode(const Operand& code,
+                                const ParameterCount& expected,
+                                const ParameterCount& actual,
+                                InvokeFlag flag) {
+  Label done;
+  InvokePrologue(expected, actual, Handle<Code>::null(), code, &done, flag);
+  if (flag == CALL_FUNCTION) {
+    call(code);
+  } else {
+    ASSERT(flag == JUMP_FUNCTION);
+    jmp(code);
+  }
+  bind(&done);
+}
+
+
+void MacroAssembler::InvokeCode(Handle<Code> code,
+                                const ParameterCount& expected,
+                                const ParameterCount& actual,
+                                RelocInfo::Mode rmode,
+                                InvokeFlag flag) {
+  Label done;
+  Operand dummy(eax);
+  InvokePrologue(expected, actual, code, dummy, &done, flag);
+  if (flag == CALL_FUNCTION) {
+    call(code, rmode);
+  } else {
+    ASSERT(flag == JUMP_FUNCTION);
+    jmp(code, rmode);
+  }
+  bind(&done);
+}
+
+
+void MacroAssembler::InvokeFunction(Register fun,
+                                    const ParameterCount& actual,
+                                    InvokeFlag flag) {
+  ASSERT(fun.is(edi));
+  mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
+  mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
+  mov(ebx, FieldOperand(edx, SharedFunctionInfo::kFormalParameterCountOffset));
+  mov(edx, FieldOperand(edx, SharedFunctionInfo::kCodeOffset));
+  lea(edx, FieldOperand(edx, Code::kHeaderSize));
+
+  ParameterCount expected(ebx);
+  InvokeCode(Operand(edx), expected, actual, flag);
+}
+
+
+void MacroAssembler::InvokeBuiltin(Builtins::JavaScript id, InvokeFlag flag) {
+  bool resolved;
+  Handle<Code> code = ResolveBuiltin(id, &resolved);
+
+  // Calls are not allowed in some stubs.
+  ASSERT(flag == JUMP_FUNCTION || allow_stub_calls());
+
+  // Rely on the assertion to check that the number of provided
+  // arguments match the expected number of arguments. Fake a
+  // parameter count to avoid emitting code to do the check.
+  ParameterCount expected(0);
+  InvokeCode(Handle<Code>(code), expected, expected,
+             RelocInfo::CODE_TARGET, flag);
+
+  const char* name = Builtins::GetName(id);
+  int argc = Builtins::GetArgumentsCount(id);
+
+  if (!resolved) {
+    uint32_t flags =
+        Bootstrapper::FixupFlagsArgumentsCount::encode(argc) |
+        Bootstrapper::FixupFlagsIsPCRelative::encode(true) |
+        Bootstrapper::FixupFlagsUseCodeObject::encode(false);
+    Unresolved entry = { pc_offset() - sizeof(int32_t), flags, name };
+    unresolved_.Add(entry);
+  }
+}
+
+
+void MacroAssembler::GetBuiltinEntry(Register target, Builtins::JavaScript id) {
+  bool resolved;
+  Handle<Code> code = ResolveBuiltin(id, &resolved);
+
+  const char* name = Builtins::GetName(id);
+  int argc = Builtins::GetArgumentsCount(id);
+
+  mov(Operand(target), Immediate(code));
+  if (!resolved) {
+    uint32_t flags =
+        Bootstrapper::FixupFlagsArgumentsCount::encode(argc) |
+        Bootstrapper::FixupFlagsIsPCRelative::encode(false) |
+        Bootstrapper::FixupFlagsUseCodeObject::encode(true);
+    Unresolved entry = { pc_offset() - sizeof(int32_t), flags, name };
+    unresolved_.Add(entry);
+  }
+  add(Operand(target), Immediate(Code::kHeaderSize - kHeapObjectTag));
+}
+
+
+Handle<Code> MacroAssembler::ResolveBuiltin(Builtins::JavaScript id,
+                                            bool* resolved) {
+  // Move the builtin function into the temporary function slot by
+  // reading it from the builtins object. NOTE: We should be able to
+  // reduce this to two instructions by putting the function table in
+  // the global object instead of the "builtins" object and by using a
+  // real register for the function.
+  mov(edx, Operand(esi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  mov(edx, FieldOperand(edx, GlobalObject::kBuiltinsOffset));
+  int builtins_offset =
+      JSBuiltinsObject::kJSBuiltinsOffset + (id * kPointerSize);
+  mov(edi, FieldOperand(edx, builtins_offset));
+
+
+  return Builtins::GetCode(id, resolved);
+}
+
+
+void MacroAssembler::Ret() {
+  ret(0);
+}
+
+
+void MacroAssembler::SetCounter(StatsCounter* counter, int value) {
+  if (FLAG_native_code_counters && counter->Enabled()) {
+    mov(Operand::StaticVariable(ExternalReference(counter)), Immediate(value));
+  }
+}
+
+
+void MacroAssembler::IncrementCounter(StatsCounter* counter, int value) {
+  ASSERT(value > 0);
+  if (FLAG_native_code_counters && counter->Enabled()) {
+    Operand operand = Operand::StaticVariable(ExternalReference(counter));
+    if (value == 1) {
+      inc(operand);
+    } else {
+      add(operand, Immediate(value));
+    }
+  }
+}
+
+
+void MacroAssembler::DecrementCounter(StatsCounter* counter, int value) {
+  ASSERT(value > 0);
+  if (FLAG_native_code_counters && counter->Enabled()) {
+    Operand operand = Operand::StaticVariable(ExternalReference(counter));
+    if (value == 1) {
+      dec(operand);
+    } else {
+      sub(operand, Immediate(value));
+    }
+  }
+}
+
+
+void MacroAssembler::Assert(Condition cc, const char* msg) {
+  if (FLAG_debug_code) Check(cc, msg);
+}
+
+
+void MacroAssembler::Check(Condition cc, const char* msg) {
+  Label L;
+  j(cc, &L, taken);
+  Abort(msg);
+  // will not return here
+  bind(&L);
+}
+
+
+void MacroAssembler::Abort(const char* msg) {
+  // We want to pass the msg string like a smi to avoid GC
+  // problems, however msg is not guaranteed to be aligned
+  // properly. Instead, we pass an aligned pointer that is
+  // a proper v8 smi, but also pass the alignment difference
+  // from the real pointer as a smi.
+  intptr_t p1 = reinterpret_cast<intptr_t>(msg);
+  intptr_t p0 = (p1 & ~kSmiTagMask) + kSmiTag;
+  ASSERT(reinterpret_cast<Object*>(p0)->IsSmi());
+#ifdef DEBUG
+  if (msg != NULL) {
+    RecordComment("Abort message: ");
+    RecordComment(msg);
+  }
+#endif
+  push(eax);
+  push(Immediate(p0));
+  push(Immediate(reinterpret_cast<intptr_t>(Smi::FromInt(p1 - p0))));
+  CallRuntime(Runtime::kAbort, 2);
+  // will not return here
+}
+
+
+CodePatcher::CodePatcher(byte* address, int size)
+    : address_(address), size_(size), masm_(address, size + Assembler::kGap) {
+  // Create a new macro assembler pointing to the address of the code to patch.
+  // The size is adjusted with kGap on order for the assembler to generate size
+  // bytes of instructions without failing with buffer size constraints.
+  ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
+}
+
+
+CodePatcher::~CodePatcher() {
+  // Indicate that code has changed.
+  CPU::FlushICache(address_, size_);
+
+  // Check that the code was patched as expected.
+  ASSERT(masm_.pc_ == address_ + size_);
+  ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
+}
+
+
+} }  // namespace v8::internal