diff --git a/src/x87/deoptimizer-x87.cc b/src/x87/deoptimizer-x87.cc
new file mode 100644
index 0000000..a76c7a7
--- /dev/null
+++ b/src/x87/deoptimizer-x87.cc
@@ -0,0 +1,471 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/v8.h"
+
+#if V8_TARGET_ARCH_X87
+
+#include "src/codegen.h"
+#include "src/deoptimizer.h"
+#include "src/full-codegen.h"
+#include "src/safepoint-table.h"
+
+namespace v8 {
+namespace internal {
+
+const int Deoptimizer::table_entry_size_ = 10;
+
+
+int Deoptimizer::patch_size() {
+  return Assembler::kCallInstructionLength;
+}
+
+
+void Deoptimizer::EnsureRelocSpaceForLazyDeoptimization(Handle<Code> code) {
+  Isolate* isolate = code->GetIsolate();
+  HandleScope scope(isolate);
+
+  // Compute the size of relocation information needed for the code
+  // patching in Deoptimizer::DeoptimizeFunction.
+  int min_reloc_size = 0;
+  int prev_pc_offset = 0;
+  DeoptimizationInputData* deopt_data =
+      DeoptimizationInputData::cast(code->deoptimization_data());
+  for (int i = 0; i < deopt_data->DeoptCount(); i++) {
+    int pc_offset = deopt_data->Pc(i)->value();
+    if (pc_offset == -1) continue;
+    DCHECK_GE(pc_offset, prev_pc_offset);
+    int pc_delta = pc_offset - prev_pc_offset;
+    // We use RUNTIME_ENTRY reloc info which has a size of 2 bytes
+    // if encodable with small pc delta encoding and up to 6 bytes
+    // otherwise.
+    if (pc_delta <= RelocInfo::kMaxSmallPCDelta) {
+      min_reloc_size += 2;
+    } else {
+      min_reloc_size += 6;
+    }
+    prev_pc_offset = pc_offset;
+  }
+
+  // If the relocation information is not big enough we create a new
+  // relocation info object that is padded with comments to make it
+  // big enough for lazy doptimization.
+  int reloc_length = code->relocation_info()->length();
+  if (min_reloc_size > reloc_length) {
+    int comment_reloc_size = RelocInfo::kMinRelocCommentSize;
+    // Padding needed.
+    int min_padding = min_reloc_size - reloc_length;
+    // Number of comments needed to take up at least that much space.
+    int additional_comments =
+        (min_padding + comment_reloc_size - 1) / comment_reloc_size;
+    // Actual padding size.
+    int padding = additional_comments * comment_reloc_size;
+    // Allocate new relocation info and copy old relocation to the end
+    // of the new relocation info array because relocation info is
+    // written and read backwards.
+    Factory* factory = isolate->factory();
+    Handle<ByteArray> new_reloc =
+        factory->NewByteArray(reloc_length + padding, TENURED);
+    MemCopy(new_reloc->GetDataStartAddress() + padding,
+            code->relocation_info()->GetDataStartAddress(), reloc_length);
+    // Create a relocation writer to write the comments in the padding
+    // space. Use position 0 for everything to ensure short encoding.
+    RelocInfoWriter reloc_info_writer(
+        new_reloc->GetDataStartAddress() + padding, 0);
+    intptr_t comment_string
+        = reinterpret_cast<intptr_t>(RelocInfo::kFillerCommentString);
+    RelocInfo rinfo(0, RelocInfo::COMMENT, comment_string, NULL);
+    for (int i = 0; i < additional_comments; ++i) {
+#ifdef DEBUG
+      byte* pos_before = reloc_info_writer.pos();
+#endif
+      reloc_info_writer.Write(&rinfo);
+      DCHECK(RelocInfo::kMinRelocCommentSize ==
+             pos_before - reloc_info_writer.pos());
+    }
+    // Replace relocation information on the code object.
+    code->set_relocation_info(*new_reloc);
+  }
+}
+
+
+void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
+  Address code_start_address = code->instruction_start();
+
+  if (FLAG_zap_code_space) {
+    // Fail hard and early if we enter this code object again.
+    byte* pointer = code->FindCodeAgeSequence();
+    if (pointer != NULL) {
+      pointer += kNoCodeAgeSequenceLength;
+    } else {
+      pointer = code->instruction_start();
+    }
+    CodePatcher patcher(pointer, 1);
+    patcher.masm()->int3();
+
+    DeoptimizationInputData* data =
+        DeoptimizationInputData::cast(code->deoptimization_data());
+    int osr_offset = data->OsrPcOffset()->value();
+    if (osr_offset > 0) {
+      CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1);
+      osr_patcher.masm()->int3();
+    }
+  }
+
+  // We will overwrite the code's relocation info in-place. Relocation info
+  // is written backward. The relocation info is the payload of a byte
+  // array.  Later on we will slide this to the start of the byte array and
+  // create a filler object in the remaining space.
+  ByteArray* reloc_info = code->relocation_info();
+  Address reloc_end_address = reloc_info->address() + reloc_info->Size();
+  RelocInfoWriter reloc_info_writer(reloc_end_address, code_start_address);
+
+  // Since the call is a relative encoding, write new
+  // reloc info.  We do not need any of the existing reloc info because the
+  // existing code will not be used again (we zap it in debug builds).
+  //
+  // Emit call to lazy deoptimization at all lazy deopt points.
+  DeoptimizationInputData* deopt_data =
+      DeoptimizationInputData::cast(code->deoptimization_data());
+#ifdef DEBUG
+  Address prev_call_address = NULL;
+#endif
+  // For each LLazyBailout instruction insert a call to the corresponding
+  // deoptimization entry.
+  for (int i = 0; i < deopt_data->DeoptCount(); i++) {
+    if (deopt_data->Pc(i)->value() == -1) continue;
+    // Patch lazy deoptimization entry.
+    Address call_address = code_start_address + deopt_data->Pc(i)->value();
+    CodePatcher patcher(call_address, patch_size());
+    Address deopt_entry = GetDeoptimizationEntry(isolate, i, LAZY);
+    patcher.masm()->call(deopt_entry, RelocInfo::NONE32);
+    // We use RUNTIME_ENTRY for deoptimization bailouts.
+    RelocInfo rinfo(call_address + 1,  // 1 after the call opcode.
+                    RelocInfo::RUNTIME_ENTRY,
+                    reinterpret_cast<intptr_t>(deopt_entry),
+                    NULL);
+    reloc_info_writer.Write(&rinfo);
+    DCHECK_GE(reloc_info_writer.pos(),
+              reloc_info->address() + ByteArray::kHeaderSize);
+    DCHECK(prev_call_address == NULL ||
+           call_address >= prev_call_address + patch_size());
+    DCHECK(call_address + patch_size() <= code->instruction_end());
+#ifdef DEBUG
+    prev_call_address = call_address;
+#endif
+  }
+
+  // Move the relocation info to the beginning of the byte array.
+  int new_reloc_size = reloc_end_address - reloc_info_writer.pos();
+  MemMove(code->relocation_start(), reloc_info_writer.pos(), new_reloc_size);
+
+  // The relocation info is in place, update the size.
+  reloc_info->set_length(new_reloc_size);
+
+  // Handle the junk part after the new relocation info. We will create
+  // a non-live object in the extra space at the end of the former reloc info.
+  Address junk_address = reloc_info->address() + reloc_info->Size();
+  DCHECK(junk_address <= reloc_end_address);
+  isolate->heap()->CreateFillerObjectAt(junk_address,
+                                        reloc_end_address - junk_address);
+}
+
+
+void Deoptimizer::FillInputFrame(Address tos, JavaScriptFrame* frame) {
+  // Set the register values. The values are not important as there are no
+  // callee saved registers in JavaScript frames, so all registers are
+  // spilled. Registers ebp and esp are set to the correct values though.
+
+  for (int i = 0; i < Register::kNumRegisters; i++) {
+    input_->SetRegister(i, i * 4);
+  }
+  input_->SetRegister(esp.code(), reinterpret_cast<intptr_t>(frame->sp()));
+  input_->SetRegister(ebp.code(), reinterpret_cast<intptr_t>(frame->fp()));
+  for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); i++) {
+    input_->SetDoubleRegister(i, 0.0);
+  }
+
+  // Fill the frame content from the actual data on the frame.
+  for (unsigned i = 0; i < input_->GetFrameSize(); i += kPointerSize) {
+    input_->SetFrameSlot(i, Memory::uint32_at(tos + i));
+  }
+}
+
+
+void Deoptimizer::SetPlatformCompiledStubRegisters(
+    FrameDescription* output_frame, CodeStubDescriptor* descriptor) {
+  intptr_t handler =
+      reinterpret_cast<intptr_t>(descriptor->deoptimization_handler());
+  int params = descriptor->GetHandlerParameterCount();
+  output_frame->SetRegister(eax.code(), params);
+  output_frame->SetRegister(ebx.code(), handler);
+}
+
+
+void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
+  for (int i = 0; i < X87Register::kMaxNumAllocatableRegisters; ++i) {
+    double double_value = input_->GetDoubleRegister(i);
+    output_frame->SetDoubleRegister(i, double_value);
+  }
+}
+
+
+bool Deoptimizer::HasAlignmentPadding(JSFunction* function) {
+  int parameter_count = function->shared()->formal_parameter_count() + 1;
+  unsigned input_frame_size = input_->GetFrameSize();
+  unsigned alignment_state_offset =
+      input_frame_size - parameter_count * kPointerSize -
+      StandardFrameConstants::kFixedFrameSize -
+      kPointerSize;
+  DCHECK(JavaScriptFrameConstants::kDynamicAlignmentStateOffset ==
+      JavaScriptFrameConstants::kLocal0Offset);
+  int32_t alignment_state = input_->GetFrameSlot(alignment_state_offset);
+  return (alignment_state == kAlignmentPaddingPushed);
+}
+
+
+#define __ masm()->
+
+void Deoptimizer::EntryGenerator::Generate() {
+  GeneratePrologue();
+
+  // Save all general purpose registers before messing with them.
+  const int kNumberOfRegisters = Register::kNumRegisters;
+
+  const int kDoubleRegsSize =
+      kDoubleSize * X87Register::kMaxNumAllocatableRegisters;
+
+  // Reserve space for x87 fp registers.
+  __ sub(esp, Immediate(kDoubleRegsSize));
+
+  __ pushad();
+
+  // GP registers are safe to use now.
+  // Save used x87 fp registers in correct position of previous reserve space.
+  Label loop, done;
+  // Get the layout of x87 stack.
+  __ sub(esp, Immediate(kPointerSize));
+  __ fistp_s(MemOperand(esp, 0));
+  __ pop(eax);
+  // Preserve stack layout in edi
+  __ mov(edi, eax);
+  // Get the x87 stack depth, the first 3 bits.
+  __ mov(ecx, eax);
+  __ and_(ecx, 0x7);
+  __ j(zero, &done, Label::kNear);
+
+  __ bind(&loop);
+  __ shr(eax, 0x3);
+  __ mov(ebx, eax);
+  __ and_(ebx, 0x7);  // Extract the st_x index into ebx.
+  // Pop TOS to the correct position. The disp(0x20) is due to pushad.
+  // The st_i should be saved to (esp + ebx * kDoubleSize + 0x20).
+  __ fstp_d(Operand(esp, ebx, times_8, 0x20));
+  __ dec(ecx);  // Decrease stack depth.
+  __ j(not_zero, &loop, Label::kNear);
+  __ bind(&done);
+
+  const int kSavedRegistersAreaSize =
+      kNumberOfRegisters * kPointerSize + kDoubleRegsSize;
+
+  // Get the bailout id from the stack.
+  __ mov(ebx, Operand(esp, kSavedRegistersAreaSize));
+
+  // Get the address of the location in the code object
+  // and compute the fp-to-sp delta in register edx.
+  __ mov(ecx, Operand(esp, kSavedRegistersAreaSize + 1 * kPointerSize));
+  __ lea(edx, Operand(esp, kSavedRegistersAreaSize + 2 * kPointerSize));
+
+  __ sub(edx, ebp);
+  __ neg(edx);
+
+  __ push(edi);
+  // Allocate a new deoptimizer object.
+  __ PrepareCallCFunction(6, eax);
+  __ mov(eax, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
+  __ mov(Operand(esp, 0 * kPointerSize), eax);  // Function.
+  __ mov(Operand(esp, 1 * kPointerSize), Immediate(type()));  // Bailout type.
+  __ mov(Operand(esp, 2 * kPointerSize), ebx);  // Bailout id.
+  __ mov(Operand(esp, 3 * kPointerSize), ecx);  // Code address or 0.
+  __ mov(Operand(esp, 4 * kPointerSize), edx);  // Fp-to-sp delta.
+  __ mov(Operand(esp, 5 * kPointerSize),
+         Immediate(ExternalReference::isolate_address(isolate())));
+  {
+    AllowExternalCallThatCantCauseGC scope(masm());
+    __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6);
+  }
+
+  __ pop(edi);
+
+  // Preserve deoptimizer object in register eax and get the input
+  // frame descriptor pointer.
+  __ mov(ebx, Operand(eax, Deoptimizer::input_offset()));
+
+  // Fill in the input registers.
+  for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
+    int offset = (i * kPointerSize) + FrameDescription::registers_offset();
+    __ pop(Operand(ebx, offset));
+  }
+
+  int double_regs_offset = FrameDescription::double_registers_offset();
+  // Fill in the double input registers.
+  for (int i = 0; i < X87Register::kMaxNumAllocatableRegisters; ++i) {
+    int dst_offset = i * kDoubleSize + double_regs_offset;
+    int src_offset = i * kDoubleSize;
+    __ fld_d(Operand(esp, src_offset));
+    __ fstp_d(Operand(ebx, dst_offset));
+  }
+
+  // Clear FPU all exceptions.
+  // TODO(ulan): Find out why the TOP register is not zero here in some cases,
+  // and check that the generated code never deoptimizes with unbalanced stack.
+  __ fnclex();
+
+  // Remove the bailout id, return address and the double registers.
+  __ add(esp, Immediate(kDoubleRegsSize + 2 * kPointerSize));
+
+  // Compute a pointer to the unwinding limit in register ecx; that is
+  // the first stack slot not part of the input frame.
+  __ mov(ecx, Operand(ebx, FrameDescription::frame_size_offset()));
+  __ add(ecx, esp);
+
+  // Unwind the stack down to - but not including - the unwinding
+  // limit and copy the contents of the activation frame to the input
+  // frame description.
+  __ lea(edx, Operand(ebx, FrameDescription::frame_content_offset()));
+  Label pop_loop_header;
+  __ jmp(&pop_loop_header);
+  Label pop_loop;
+  __ bind(&pop_loop);
+  __ pop(Operand(edx, 0));
+  __ add(edx, Immediate(sizeof(uint32_t)));
+  __ bind(&pop_loop_header);
+  __ cmp(ecx, esp);
+  __ j(not_equal, &pop_loop);
+
+  // Compute the output frame in the deoptimizer.
+  __ push(edi);
+  __ push(eax);
+  __ PrepareCallCFunction(1, ebx);
+  __ mov(Operand(esp, 0 * kPointerSize), eax);
+  {
+    AllowExternalCallThatCantCauseGC scope(masm());
+    __ CallCFunction(
+        ExternalReference::compute_output_frames_function(isolate()), 1);
+  }
+  __ pop(eax);
+  __ pop(edi);
+
+  // If frame was dynamically aligned, pop padding.
+  Label no_padding;
+  __ cmp(Operand(eax, Deoptimizer::has_alignment_padding_offset()),
+         Immediate(0));
+  __ j(equal, &no_padding);
+  __ pop(ecx);
+  if (FLAG_debug_code) {
+    __ cmp(ecx, Immediate(kAlignmentZapValue));
+    __ Assert(equal, kAlignmentMarkerExpected);
+  }
+  __ bind(&no_padding);
+
+  // Replace the current frame with the output frames.
+  Label outer_push_loop, inner_push_loop,
+      outer_loop_header, inner_loop_header;
+  // Outer loop state: eax = current FrameDescription**, edx = one past the
+  // last FrameDescription**.
+  __ mov(edx, Operand(eax, Deoptimizer::output_count_offset()));
+  __ mov(eax, Operand(eax, Deoptimizer::output_offset()));
+  __ lea(edx, Operand(eax, edx, times_4, 0));
+  __ jmp(&outer_loop_header);
+  __ bind(&outer_push_loop);
+  // Inner loop state: ebx = current FrameDescription*, ecx = loop index.
+  __ mov(ebx, Operand(eax, 0));
+  __ mov(ecx, Operand(ebx, FrameDescription::frame_size_offset()));
+  __ jmp(&inner_loop_header);
+  __ bind(&inner_push_loop);
+  __ sub(ecx, Immediate(sizeof(uint32_t)));
+  __ push(Operand(ebx, ecx, times_1, FrameDescription::frame_content_offset()));
+  __ bind(&inner_loop_header);
+  __ test(ecx, ecx);
+  __ j(not_zero, &inner_push_loop);
+  __ add(eax, Immediate(kPointerSize));
+  __ bind(&outer_loop_header);
+  __ cmp(eax, edx);
+  __ j(below, &outer_push_loop);
+
+
+  // In case of a failed STUB, we have to restore the x87 stack.
+  // x87 stack layout is in edi.
+  Label loop2, done2;
+  // Get the x87 stack depth, the first 3 bits.
+  __ mov(ecx, edi);
+  __ and_(ecx, 0x7);
+  __ j(zero, &done2, Label::kNear);
+
+  __ lea(ecx, Operand(ecx, ecx, times_2, 0));
+  __ bind(&loop2);
+  __ mov(eax, edi);
+  __ shr_cl(eax);
+  __ and_(eax, 0x7);
+  __ fld_d(Operand(ebx, eax, times_8, double_regs_offset));
+  __ sub(ecx, Immediate(0x3));
+  __ j(not_zero, &loop2, Label::kNear);
+  __ bind(&done2);
+
+  // Push state, pc, and continuation from the last output frame.
+  __ push(Operand(ebx, FrameDescription::state_offset()));
+  __ push(Operand(ebx, FrameDescription::pc_offset()));
+  __ push(Operand(ebx, FrameDescription::continuation_offset()));
+
+
+  // Push the registers from the last output frame.
+  for (int i = 0; i < kNumberOfRegisters; i++) {
+    int offset = (i * kPointerSize) + FrameDescription::registers_offset();
+    __ push(Operand(ebx, offset));
+  }
+
+  // Restore the registers from the stack.
+  __ popad();
+
+  // Return to the continuation point.
+  __ ret(0);
+}
+
+
+void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
+  // Create a sequence of deoptimization entries.
+  Label done;
+  for (int i = 0; i < count(); i++) {
+    int start = masm()->pc_offset();
+    USE(start);
+    __ push_imm32(i);
+    __ jmp(&done);
+    DCHECK(masm()->pc_offset() - start == table_entry_size_);
+  }
+  __ bind(&done);
+}
+
+
+void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) {
+  SetFrameSlot(offset, value);
+}
+
+
+void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) {
+  SetFrameSlot(offset, value);
+}
+
+
+void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value) {
+  // No out-of-line constant pool support.
+  UNREACHABLE();
+}
+
+
+#undef __
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_TARGET_ARCH_X87