text: // 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.
  
  #if V8_TARGET_ARCH_X87
  
  #include "src/base/bits.h"
  #include "src/base/division-by-constant.h"
  #include "src/bootstrapper.h"
  #include "src/codegen.h"
  #include "src/cpu-profiler.h"
  #include "src/debug/debug.h"
  #include "src/runtime/runtime.h"
  #include "src/x87/frames-x87.h"
  #include "src/x87/macro-assembler-x87.h"
  
  namespace v8 {
  namespace internal {
  
  // -------------------------------------------------------------------------
  // MacroAssembler implementation.
  
  MacroAssembler::MacroAssembler(Isolate* arg_isolate, void* buffer, int size)
      : Assembler(arg_isolate, buffer, size),
        generating_stub_(false),
        has_frame_(false) {
    if (isolate() != NULL) {
      // TODO(titzer): should we just use a null handle here instead?
      code_object_ = Handle<Object>(isolate()->heap()->undefined_value(),
                                    isolate());
    }
  }
  
  
  void MacroAssembler::Load(Register dst, const Operand& src, Representation r) {
    DCHECK(!r.IsDouble());
    if (r.IsInteger8()) {
      movsx_b(dst, src);
    } else if (r.IsUInteger8()) {
      movzx_b(dst, src);
    } else if (r.IsInteger16()) {
      movsx_w(dst, src);
    } else if (r.IsUInteger16()) {
      movzx_w(dst, src);
    } else {
      mov(dst, src);
    }
  }
  
  
  void MacroAssembler::Store(Register src, const Operand& dst, Representation r) {
    DCHECK(!r.IsDouble());
    if (r.IsInteger8() || r.IsUInteger8()) {
      mov_b(dst, src);
    } else if (r.IsInteger16() || r.IsUInteger16()) {
      mov_w(dst, src);
    } else {
      if (r.IsHeapObject()) {
        AssertNotSmi(src);
      } else if (r.IsSmi()) {
        AssertSmi(src);
      }
      mov(dst, src);
    }
  }
  
  
  void MacroAssembler::LoadRoot(Register destination, Heap::RootListIndex index) {
    if (isolate()->heap()->RootCanBeTreatedAsConstant(index)) {
      mov(destination, isolate()->heap()->root_handle(index));
      return;
    }
    ExternalReference roots_array_start =
        ExternalReference::roots_array_start(isolate());
    mov(destination, Immediate(index));
    mov(destination, Operand::StaticArray(destination,
                                          times_pointer_size,
                                          roots_array_start));
  }
  
  
  void MacroAssembler::StoreRoot(Register source,
                                 Register scratch,
                                 Heap::RootListIndex index) {
    DCHECK(Heap::RootCanBeWrittenAfterInitialization(index));
    ExternalReference roots_array_start =
        ExternalReference::roots_array_start(isolate());
    mov(scratch, Immediate(index));
    mov(Operand::StaticArray(scratch, times_pointer_size, roots_array_start),
        source);
  }
  
  
  void MacroAssembler::CompareRoot(Register with,
                                   Register scratch,
                                   Heap::RootListIndex index) {
    ExternalReference roots_array_start =
        ExternalReference::roots_array_start(isolate());
    mov(scratch, Immediate(index));
    cmp(with, Operand::StaticArray(scratch,
                                  times_pointer_size,
                                  roots_array_start));
  }
  
  
  void MacroAssembler::CompareRoot(Register with, Heap::RootListIndex index) {
    DCHECK(isolate()->heap()->RootCanBeTreatedAsConstant(index));
    cmp(with, isolate()->heap()->root_handle(index));
  }
  
  
  void MacroAssembler::CompareRoot(const Operand& with,
                                   Heap::RootListIndex index) {
    DCHECK(isolate()->heap()->RootCanBeTreatedAsConstant(index));
    cmp(with, isolate()->heap()->root_handle(index));
  }
  
  
  void MacroAssembler::InNewSpace(
      Register object,
      Register scratch,
      Condition cc,
      Label* condition_met,
      Label::Distance condition_met_distance) {
    DCHECK(cc == equal || cc == not_equal);
    if (scratch.is(object)) {
      and_(scratch, Immediate(~Page::kPageAlignmentMask));
    } else {
      mov(scratch, Immediate(~Page::kPageAlignmentMask));
      and_(scratch, object);
    }
    // Check that we can use a test_b.
    DCHECK(MemoryChunk::IN_FROM_SPACE < 8);
    DCHECK(MemoryChunk::IN_TO_SPACE < 8);
    int mask = (1 << MemoryChunk::IN_FROM_SPACE)
             | (1 << MemoryChunk::IN_TO_SPACE);
    // If non-zero, the page belongs to new-space.
    test_b(Operand(scratch, MemoryChunk::kFlagsOffset),
           static_cast<uint8_t>(mask));
    j(cc, condition_met, condition_met_distance);
  }
  
  
  void MacroAssembler::RememberedSetHelper(
      Register object,  // Only used for debug checks.
      Register addr, Register scratch, SaveFPRegsMode save_fp,
      MacroAssembler::RememberedSetFinalAction and_then) {
    Label done;
    if (emit_debug_code()) {
      Label ok;
      JumpIfNotInNewSpace(object, scratch, &ok, Label::kNear);
      int3();
      bind(&ok);
    }
    // Load store buffer top.
    ExternalReference store_buffer =
        ExternalReference::store_buffer_top(isolate());
    mov(scratch, Operand::StaticVariable(store_buffer));
    // Store pointer to buffer.
    mov(Operand(scratch, 0), addr);
    // Increment buffer top.
    add(scratch, Immediate(kPointerSize));
    // Write back new top of buffer.
    mov(Operand::StaticVariable(store_buffer), scratch);
    // Call stub on end of buffer.
    // Check for end of buffer.
    test(scratch, Immediate(StoreBuffer::kStoreBufferOverflowBit));
    if (and_then == kReturnAtEnd) {
      Label buffer_overflowed;
      j(not_equal, &buffer_overflowed, Label::kNear);
      ret(0);
      bind(&buffer_overflowed);
    } else {
      DCHECK(and_then == kFallThroughAtEnd);
      j(equal, &done, Label::kNear);
    }
    StoreBufferOverflowStub store_buffer_overflow(isolate(), save_fp);
    CallStub(&store_buffer_overflow);
    if (and_then == kReturnAtEnd) {
      ret(0);
    } else {
      DCHECK(and_then == kFallThroughAtEnd);
      bind(&done);
    }
  }
  
  
  void MacroAssembler::ClampTOSToUint8(Register result_reg) {
    Label done, conv_failure;
    sub(esp, Immediate(kPointerSize));
    fnclex();
    fist_s(Operand(esp, 0));
    pop(result_reg);
    X87CheckIA();
    j(equal, &conv_failure, Label::kNear);
    test(result_reg, Immediate(0xFFFFFF00));
    j(zero, &done, Label::kNear);
    setcc(sign, result_reg);
    sub(result_reg, Immediate(1));
    and_(result_reg, Immediate(255));
    jmp(&done, Label::kNear);
    bind(&conv_failure);
    fnclex();
    fldz();
    fld(1);
    FCmp();
    setcc(below, result_reg);  // 1 if negative, 0 if positive.
    dec_b(result_reg);         // 0 if negative, 255 if positive.
    bind(&done);
  }
  
  
  void MacroAssembler::ClampUint8(Register reg) {
    Label done;
    test(reg, Immediate(0xFFFFFF00));
    j(zero, &done, Label::kNear);
    setcc(negative, reg);  // 1 if negative, 0 if positive.
    dec_b(reg);  // 0 if negative, 255 if positive.
    bind(&done);
  }
  
  
  void MacroAssembler::SlowTruncateToI(Register result_reg,
                                       Register input_reg,
                                       int offset) {
    DoubleToIStub stub(isolate(), input_reg, result_reg, offset, true);
    call(stub.GetCode(), RelocInfo::CODE_TARGET);
  }
  
  
  void MacroAssembler::TruncateX87TOSToI(Register result_reg) {
    sub(esp, Immediate(kDoubleSize));
    fst_d(MemOperand(esp, 0));
    SlowTruncateToI(result_reg, esp, 0);
    add(esp, Immediate(kDoubleSize));
  }
  
  
  void MacroAssembler::X87TOSToI(Register result_reg,
                                 MinusZeroMode minus_zero_mode,
                                 Label* lost_precision, Label* is_nan,
                                 Label* minus_zero, Label::Distance dst) {
    Label done;
    sub(esp, Immediate(kPointerSize));
    fld(0);
    fist_s(MemOperand(esp, 0));
    fild_s(MemOperand(esp, 0));
    pop(result_reg);
    FCmp();
    j(not_equal, lost_precision, dst);
    j(parity_even, is_nan, dst);
    if (minus_zero_mode == FAIL_ON_MINUS_ZERO) {
      test(result_reg, Operand(result_reg));
      j(not_zero, &done, Label::kNear);
      // To check for minus zero, we load the value again as float, and check
      // if that is still 0.
      sub(esp, Immediate(kPointerSize));
      fst_s(MemOperand(esp, 0));
      pop(result_reg);
      test(result_reg, Operand(result_reg));
      j(not_zero, minus_zero, dst);
    }
    bind(&done);
  }
  
  
  void MacroAssembler::TruncateHeapNumberToI(Register result_reg,
                                             Register input_reg) {
    Label done, slow_case;
  
    SlowTruncateToI(result_reg, input_reg);
    bind(&done);
  }
  
  
  void MacroAssembler::LoadUint32NoSSE2(const Operand& src) {
    Label done;
    push(src);
    fild_s(Operand(esp, 0));
    cmp(src, Immediate(0));
    j(not_sign, &done, Label::kNear);
    ExternalReference uint32_bias =
          ExternalReference::address_of_uint32_bias();
    fld_d(Operand::StaticVariable(uint32_bias));
    faddp(1);
    bind(&done);
    add(esp, Immediate(kPointerSize));
  }
  
  
  void MacroAssembler::RecordWriteArray(
      Register object, Register value, Register index, SaveFPRegsMode save_fp,
      RememberedSetAction remembered_set_action, SmiCheck smi_check,
      PointersToHereCheck pointers_to_here_check_for_value) {
    // First, check if a write barrier is even needed. The tests below
    // catch stores of Smis.
    Label done;
  
    // Skip barrier if writing a smi.
    if (smi_check == INLINE_SMI_CHECK) {
      DCHECK_EQ(0, kSmiTag);
      test(value, Immediate(kSmiTagMask));
      j(zero, &done);
    }
  
    // 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.
    Register dst = index;
    lea(dst, Operand(object, index, times_half_pointer_size,
                     FixedArray::kHeaderSize - kHeapObjectTag));
  
    RecordWrite(object, dst, value, save_fp, remembered_set_action,
                OMIT_SMI_CHECK, pointers_to_here_check_for_value);
  
    bind(&done);
  
    // Clobber clobbered input registers when running with the debug-code flag
    // turned on to provoke errors.
    if (emit_debug_code()) {
      mov(value, Immediate(bit_cast<int32_t>(kZapValue)));
      mov(index, Immediate(bit_cast<int32_t>(kZapValue)));
    }
  }
  
  
  void MacroAssembler::RecordWriteField(
      Register object, int offset, Register value, Register dst,
      SaveFPRegsMode save_fp, RememberedSetAction remembered_set_action,
      SmiCheck smi_check, PointersToHereCheck pointers_to_here_check_for_value) {
    // First, check if a write barrier is even needed. The tests below
    // catch stores of Smis.
    Label done;
  
    // Skip barrier if writing a smi.
    if (smi_check == INLINE_SMI_CHECK) {
      JumpIfSmi(value, &done, Label::kNear);
    }
  
    // Although the object register is tagged, the offset is relative to the start
    // of the object, so so offset must be a multiple of kPointerSize.
    DCHECK(IsAligned(offset, kPointerSize));
  
    lea(dst, FieldOperand(object, offset));
    if (emit_debug_code()) {
      Label ok;
      test_b(dst, (1 << kPointerSizeLog2) - 1);
      j(zero, &ok, Label::kNear);
      int3();
      bind(&ok);
    }
  
    RecordWrite(object, dst, value, save_fp, remembered_set_action,
                OMIT_SMI_CHECK, pointers_to_here_check_for_value);
  
    bind(&done);
  
    // Clobber clobbered input registers when running with the debug-code flag
    // turned on to provoke errors.
    if (emit_debug_code()) {
      mov(value, Immediate(bit_cast<int32_t>(kZapValue)));
      mov(dst, Immediate(bit_cast<int32_t>(kZapValue)));
    }
  }
  
  
  void MacroAssembler::RecordWriteForMap(Register object, Handle<Map> map,
                                         Register scratch1, Register scratch2,
                                         SaveFPRegsMode save_fp) {
    Label done;
  
    Register address = scratch1;
    Register value = scratch2;
    if (emit_debug_code()) {
      Label ok;
      lea(address, FieldOperand(object, HeapObject::kMapOffset));
      test_b(address, (1 << kPointerSizeLog2) - 1);
      j(zero, &ok, Label::kNear);
      int3();
      bind(&ok);
    }
  
    DCHECK(!object.is(value));
    DCHECK(!object.is(address));
    DCHECK(!value.is(address));
    AssertNotSmi(object);
  
    if (!FLAG_incremental_marking) {
      return;
    }
  
    // Compute the address.
    lea(address, FieldOperand(object, HeapObject::kMapOffset));
  
    // A single check of the map's pages interesting flag suffices, since it is
    // only set during incremental collection, and then it's also guaranteed that
    // the from object's page's interesting flag is also set.  This optimization
    // relies on the fact that maps can never be in new space.
    DCHECK(!isolate()->heap()->InNewSpace(*map));
    CheckPageFlagForMap(map,
                        MemoryChunk::kPointersToHereAreInterestingMask,
                        zero,
                        &done,
                        Label::kNear);
  
    RecordWriteStub stub(isolate(), object, value, address, OMIT_REMEMBERED_SET,
                         save_fp);
    CallStub(&stub);
  
    bind(&done);
  
    // Count number of write barriers in generated code.
    isolate()->counters()->write_barriers_static()->Increment();
    IncrementCounter(isolate()->counters()->write_barriers_dynamic(), 1);
  
    // Clobber clobbered input registers when running with the debug-code flag
    // turned on to provoke errors.
    if (emit_debug_code()) {
      mov(value, Immediate(bit_cast<int32_t>(kZapValue)));
      mov(scratch1, Immediate(bit_cast<int32_t>(kZapValue)));
      mov(scratch2, Immediate(bit_cast<int32_t>(kZapValue)));
    }
  }
  
  
  void MacroAssembler::RecordWrite(
      Register object, Register address, Register value, SaveFPRegsMode fp_mode,
      RememberedSetAction remembered_set_action, SmiCheck smi_check,
      PointersToHereCheck pointers_to_here_check_for_value) {
    DCHECK(!object.is(value));
    DCHECK(!object.is(address));
    DCHECK(!value.is(address));
    AssertNotSmi(object);
  
    if (remembered_set_action == OMIT_REMEMBERED_SET &&
        !FLAG_incremental_marking) {
      return;
    }
  
    if (emit_debug_code()) {
      Label ok;
      cmp(value, Operand(address, 0));
      j(equal, &ok, Label::kNear);
      int3();
      bind(&ok);
    }
  
    // First, check if a write barrier is even needed. The tests below
    // catch stores of Smis and stores into young gen.
    Label done;
  
    if (smi_check == INLINE_SMI_CHECK) {
      // Skip barrier if writing a smi.
      JumpIfSmi(value, &done, Label::kNear);
    }
  
    if (pointers_to_here_check_for_value != kPointersToHereAreAlwaysInteresting) {
      CheckPageFlag(value,
                    value,  // Used as scratch.
                    MemoryChunk::kPointersToHereAreInterestingMask,
                    zero,
                    &done,
                    Label::kNear);
    }
    CheckPageFlag(object,
                  value,  // Used as scratch.
                  MemoryChunk::kPointersFromHereAreInterestingMask,
                  zero,
                  &done,
                  Label::kNear);
  
    RecordWriteStub stub(isolate(), object, value, address, remembered_set_action,
                         fp_mode);
    CallStub(&stub);
  
    bind(&done);
  
    // Count number of write barriers in generated code.
    isolate()->counters()->write_barriers_static()->Increment();
    IncrementCounter(isolate()->counters()->write_barriers_dynamic(), 1);
  
    // Clobber clobbered registers when running with the debug-code flag
    // turned on to provoke errors.
    if (emit_debug_code()) {
      mov(address, Immediate(bit_cast<int32_t>(kZapValue)));
      mov(value, Immediate(bit_cast<int32_t>(kZapValue)));
    }
  }
  
  
  void MacroAssembler::DebugBreak() {
    Move(eax, Immediate(0));
    mov(ebx, Immediate(ExternalReference(Runtime::kHandleDebuggerStatement,
                                         isolate())));
    CEntryStub ces(isolate(), 1);
    call(ces.GetCode(), RelocInfo::DEBUGGER_STATEMENT);
  }
  
  
  bool MacroAssembler::IsUnsafeImmediate(const Immediate& x) {
    static const int kMaxImmediateBits = 17;
    if (!RelocInfo::IsNone(x.rmode_)) return false;
    return !is_intn(x.x_, kMaxImmediateBits);
  }
  
  
  void MacroAssembler::SafeMove(Register dst, const Immediate& x) {
    if (IsUnsafeImmediate(x) && jit_cookie() != 0) {
      Move(dst, Immediate(x.x_ ^ jit_cookie()));
      xor_(dst, jit_cookie());
    } else {
      Move(dst, x);
    }
  }
  
  
  void MacroAssembler::SafePush(const Immediate& x) {
    if (IsUnsafeImmediate(x) && jit_cookie() != 0) {
      push(Immediate(x.x_ ^ jit_cookie()));
      xor_(Operand(esp, 0), Immediate(jit_cookie()));
    } else {
      push(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::CheckFastElements(Register map,
                                         Label* fail,
                                         Label::Distance distance) {
    STATIC_ASSERT(FAST_SMI_ELEMENTS == 0);
    STATIC_ASSERT(FAST_HOLEY_SMI_ELEMENTS == 1);
    STATIC_ASSERT(FAST_ELEMENTS == 2);
    STATIC_ASSERT(FAST_HOLEY_ELEMENTS == 3);
    cmpb(FieldOperand(map, Map::kBitField2Offset),
         Map::kMaximumBitField2FastHoleyElementValue);
    j(above, fail, distance);
  }
  
  
  void MacroAssembler::CheckFastObjectElements(Register map,
                                               Label* fail,
                                               Label::Distance distance) {
    STATIC_ASSERT(FAST_SMI_ELEMENTS == 0);
    STATIC_ASSERT(FAST_HOLEY_SMI_ELEMENTS == 1);
    STATIC_ASSERT(FAST_ELEMENTS == 2);
    STATIC_ASSERT(FAST_HOLEY_ELEMENTS == 3);
    cmpb(FieldOperand(map, Map::kBitField2Offset),
         Map::kMaximumBitField2FastHoleySmiElementValue);
    j(below_equal, fail, distance);
    cmpb(FieldOperand(map, Map::kBitField2Offset),
         Map::kMaximumBitField2FastHoleyElementValue);
    j(above, fail, distance);
  }
  
  
  void MacroAssembler::CheckFastSmiElements(Register map,
                                            Label* fail,
                                            Label::Distance distance) {
    STATIC_ASSERT(FAST_SMI_ELEMENTS == 0);
    STATIC_ASSERT(FAST_HOLEY_SMI_ELEMENTS == 1);
    cmpb(FieldOperand(map, Map::kBitField2Offset),
         Map::kMaximumBitField2FastHoleySmiElementValue);
    j(above, fail, distance);
  }
  
  
  void MacroAssembler::StoreNumberToDoubleElements(
      Register maybe_number,
      Register elements,
      Register key,
      Register scratch,
      Label* fail,
      int elements_offset) {
    Label smi_value, done, maybe_nan, not_nan, is_nan, have_double_value;
    JumpIfSmi(maybe_number, &smi_value, Label::kNear);
  
    CheckMap(maybe_number,
             isolate()->factory()->heap_number_map(),
             fail,
             DONT_DO_SMI_CHECK);
  
    fld_d(FieldOperand(maybe_number, HeapNumber::kValueOffset));
    jmp(&done, Label::kNear);
  
    bind(&smi_value);
    // Value is a smi. Convert to a double and store.
    // Preserve original value.
    mov(scratch, maybe_number);
    SmiUntag(scratch);
    push(scratch);
    fild_s(Operand(esp, 0));
    pop(scratch);
    bind(&done);
    fstp_d(FieldOperand(elements, key, times_4,
                        FixedDoubleArray::kHeaderSize - elements_offset));
  }
  
  
  void MacroAssembler::CompareMap(Register obj, Handle<Map> map) {
    cmp(FieldOperand(obj, HeapObject::kMapOffset), map);
  }
  
  
  void MacroAssembler::CheckMap(Register obj,
                                Handle<Map> map,
                                Label* fail,
                                SmiCheckType smi_check_type) {
    if (smi_check_type == DO_SMI_CHECK) {
      JumpIfSmi(obj, fail);
    }
  
    CompareMap(obj, map);
    j(not_equal, fail);
  }
  
  
  void MacroAssembler::DispatchWeakMap(Register obj, Register scratch1,
                                       Register scratch2, Handle<WeakCell> cell,
                                       Handle<Code> success,
                                       SmiCheckType smi_check_type) {
    Label fail;
    if (smi_check_type == DO_SMI_CHECK) {
      JumpIfSmi(obj, &fail);
    }
    mov(scratch1, FieldOperand(obj, HeapObject::kMapOffset));
    CmpWeakValue(scratch1, cell, scratch2);
    j(equal, success);
  
    bind(&fail);
  }
  
  
  Condition MacroAssembler::IsObjectStringType(Register heap_object,
                                               Register map,
                                               Register instance_type) {
    mov(map, FieldOperand(heap_object, HeapObject::kMapOffset));
    movzx_b(instance_type, FieldOperand(map, Map::kInstanceTypeOffset));
    STATIC_ASSERT(kNotStringTag != 0);
    test(instance_type, Immediate(kIsNotStringMask));
    return zero;
  }
  
  
  Condition MacroAssembler::IsObjectNameType(Register heap_object,
                                             Register map,
                                             Register instance_type) {
    mov(map, FieldOperand(heap_object, HeapObject::kMapOffset));
    movzx_b(instance_type, FieldOperand(map, Map::kInstanceTypeOffset));
    cmpb(instance_type, static_cast<uint8_t>(LAST_NAME_TYPE));
    return below_equal;
  }
  
  
  void MacroAssembler::FCmp() {
    fucompp();
    push(eax);
    fnstsw_ax();
    sahf();
    pop(eax);
  }
  
  
  void MacroAssembler::FXamMinusZero() {
    fxam();
    push(eax);
    fnstsw_ax();
    and_(eax, Immediate(0x4700));
    // For minus zero, C3 == 1 && C1 == 1.
    cmp(eax, Immediate(0x4200));
    pop(eax);
    fstp(0);
  }
  
  
  void MacroAssembler::FXamSign() {
    fxam();
    push(eax);
    fnstsw_ax();
    // For negative value (including -0.0), C1 == 1.
    and_(eax, Immediate(0x0200));
    pop(eax);
    fstp(0);
  }
  
  
  void MacroAssembler::X87CheckIA() {
    push(eax);
    fnstsw_ax();
    // For #IA, IE == 1 && SF == 0.
    and_(eax, Immediate(0x0041));
    cmp(eax, Immediate(0x0001));
    pop(eax);
  }
  
  
  // rc=00B, round to nearest.
  // rc=01B, round down.
  // rc=10B, round up.
  // rc=11B, round toward zero.
  void MacroAssembler::X87SetRC(int rc) {
    sub(esp, Immediate(kPointerSize));
    fnstcw(MemOperand(esp, 0));
    and_(MemOperand(esp, 0), Immediate(0xF3FF));
    or_(MemOperand(esp, 0), Immediate(rc));
    fldcw(MemOperand(esp, 0));
    add(esp, Immediate(kPointerSize));
  }
  
  
  void MacroAssembler::X87SetFPUCW(int cw) {
    RecordComment("-- X87SetFPUCW start --");
    push(Immediate(cw));
    fldcw(MemOperand(esp, 0));
    add(esp, Immediate(kPointerSize));
    RecordComment("-- X87SetFPUCW end--");
  }
  
  
  void MacroAssembler::AssertNumber(Register object) {
    if (emit_debug_code()) {
      Label ok;
      JumpIfSmi(object, &ok);
      cmp(FieldOperand(object, HeapObject::kMapOffset),
          isolate()->factory()->heap_number_map());
      Check(equal, kOperandNotANumber);
      bind(&ok);
    }
  }
  
  
  void MacroAssembler::AssertSmi(Register object) {
    if (emit_debug_code()) {
      test(object, Immediate(kSmiTagMask));
      Check(equal, kOperandIsNotASmi);
    }
  }
  
  
  void MacroAssembler::AssertString(Register object) {
    if (emit_debug_code()) {
      test(object, Immediate(kSmiTagMask));
      Check(not_equal, kOperandIsASmiAndNotAString);
      push(object);
      mov(object, FieldOperand(object, HeapObject::kMapOffset));
      CmpInstanceType(object, FIRST_NONSTRING_TYPE);
      pop(object);
      Check(below, kOperandIsNotAString);
    }
  }
  
  
  void MacroAssembler::AssertName(Register object) {
    if (emit_debug_code()) {
      test(object, Immediate(kSmiTagMask));
      Check(not_equal, kOperandIsASmiAndNotAName);
      push(object);
      mov(object, FieldOperand(object, HeapObject::kMapOffset));
      CmpInstanceType(object, LAST_NAME_TYPE);
      pop(object);
      Check(below_equal, kOperandIsNotAName);
    }
  }
  
  
  void MacroAssembler::AssertUndefinedOrAllocationSite(Register object) {
    if (emit_debug_code()) {
      Label done_checking;
      AssertNotSmi(object);
      cmp(object, isolate()->factory()->undefined_value());
      j(equal, &done_checking);
      cmp(FieldOperand(object, 0),
          Immediate(isolate()->factory()->allocation_site_map()));
      Assert(equal, kExpectedUndefinedOrCell);
      bind(&done_checking);
    }
  }
  
  
  void MacroAssembler::AssertNotSmi(Register object) {
    if (emit_debug_code()) {
      test(object, Immediate(kSmiTagMask));
      Check(not_equal, kOperandIsASmi);
    }
  }
  
  
  void MacroAssembler::StubPrologue() {
    push(ebp);  // Caller's frame pointer.
    mov(ebp, esp);
    push(esi);  // Callee's context.
    push(Immediate(Smi::FromInt(StackFrame::STUB)));
  }
  
  
  void MacroAssembler::Prologue(bool code_pre_aging) {
    PredictableCodeSizeScope predictible_code_size_scope(this,
        kNoCodeAgeSequenceLength);
    if (code_pre_aging) {
        // Pre-age the code.
      call(isolate()->builtins()->MarkCodeAsExecutedOnce(),
          RelocInfo::CODE_AGE_SEQUENCE);
      Nop(kNoCodeAgeSequenceLength - Assembler::kCallInstructionLength);
    } else {
      push(ebp);  // Caller's frame pointer.
      mov(ebp, esp);
      push(esi);  // Callee's context.
      push(edi);  // Callee's JS function.
    }
  }
  
  
  void MacroAssembler::EnterFrame(StackFrame::Type type,
                                  bool load_constant_pool_pointer_reg) {
    // Out-of-line constant pool not implemented on x87.
    UNREACHABLE();
  }
  
  
  void MacroAssembler::EnterFrame(StackFrame::Type type) {
    push(ebp);
    mov(ebp, esp);
    push(esi);
    push(Immediate(Smi::FromInt(type)));
    push(Immediate(CodeObject()));
    if (emit_debug_code()) {
      cmp(Operand(esp, 0), Immediate(isolate()->factory()->undefined_value()));
      Check(not_equal, kCodeObjectNotProperlyPatched);
    }
  }
  
  
  void MacroAssembler::LeaveFrame(StackFrame::Type type) {
    if (emit_debug_code()) {
      cmp(Operand(ebp, StandardFrameConstants::kMarkerOffset),
          Immediate(Smi::FromInt(type)));
      Check(equal, kStackFrameTypesMustMatch);
    }
    leave();
  }
  
  
  void MacroAssembler::EnterExitFramePrologue() {
    // Set up the frame structure on the stack.
    DCHECK(ExitFrameConstants::kCallerSPDisplacement == +2 * kPointerSize);
    DCHECK(ExitFrameConstants::kCallerPCOffset == +1 * kPointerSize);
    DCHECK(ExitFrameConstants::kCallerFPOffset ==  0 * kPointerSize);
    push(ebp);
    mov(ebp, esp);
  
    // Reserve room for entry stack pointer and push the code object.
    DCHECK(ExitFrameConstants::kSPOffset  == -1 * kPointerSize);
    push(Immediate(0));  // Saved entry sp, patched before call.
    push(Immediate(CodeObject()));  // Accessed from ExitFrame::code_slot.
  
    // Save the frame pointer and the context in top.
    ExternalReference c_entry_fp_address(Isolate::kCEntryFPAddress, isolate());
    ExternalReference context_address(Isolate::kContextAddress, isolate());
    ExternalReference c_function_address(Isolate::kCFunctionAddress, isolate());
    mov(Operand::StaticVariable(c_entry_fp_address), ebp);
    mov(Operand::StaticVariable(context_address), esi);
    mov(Operand::StaticVariable(c_function_address), ebx);
  }
  
  
  void MacroAssembler::EnterExitFrameEpilogue(int argc, bool save_doubles) {
    // Optionally save FPU state.
    if (save_doubles) {
      // Store FPU state to m108byte.
      int space = 108 + argc * kPointerSize;
      sub(esp, Immediate(space));
      const int offset = -2 * kPointerSize;  // entry fp + code object.
      fnsave(MemOperand(ebp, offset - 108));
    } else {
      sub(esp, Immediate(argc * kPointerSize));
    }
  
    // Get the required frame alignment for the OS.
    const int kFrameAlignment = base::OS::ActivationFrameAlignment();
    if (kFrameAlignment > 0) {
      DCHECK(base::bits::IsPowerOfTwo32(kFrameAlignment));
      and_(esp, -kFrameAlignment);
    }
  
    // Patch the saved entry sp.
    mov(Operand(ebp, ExitFrameConstants::kSPOffset), esp);
  }
  
  
  void MacroAssembler::EnterExitFrame(bool save_doubles) {
    EnterExitFramePrologue();
  
    // Set up argc and argv in callee-saved registers.
    int offset = StandardFrameConstants::kCallerSPOffset - kPointerSize;
    mov(edi, eax);
    lea(esi, Operand(ebp, eax, times_4, offset));
  
    // Reserve space for argc, argv and isolate.
    EnterExitFrameEpilogue(3, save_doubles);
  }
  
  
  void MacroAssembler::EnterApiExitFrame(int argc) {
    EnterExitFramePrologue();
    EnterExitFrameEpilogue(argc, false);
  }
  
  
  void MacroAssembler::LeaveExitFrame(bool save_doubles) {
    // Optionally restore FPU state.
    if (save_doubles) {
      const int offset = -2 * kPointerSize;
      frstor(MemOperand(ebp, offset - 108));
    }
  
    // 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));
  
    // Push the return address to get ready to return.
    push(ecx);
  
    LeaveExitFrameEpilogue(true);
  }
  
  
  void MacroAssembler::LeaveExitFrameEpilogue(bool restore_context) {
    // Restore current context from top and clear it in debug mode.
    ExternalReference context_address(Isolate::kContextAddress, isolate());
    if (restore_context) {
      mov(esi, Operand::StaticVariable(context_address));
    }
  #ifdef DEBUG
    mov(Operand::StaticVariable(context_address), Immediate(0));
  #endif
  
    // Clear the top frame.
    ExternalReference c_entry_fp_address(Isolate::kCEntryFPAddress,
                                         isolate());
    mov(Operand::StaticVariable(c_entry_fp_address), Immediate(0));
  }
  
  
  void MacroAssembler::LeaveApiExitFrame(bool restore_context) {
    mov(esp, ebp);
    pop(ebp);
  
    LeaveExitFrameEpilogue(restore_context);
  }
  
  
  void MacroAssembler::PushStackHandler() {
    // Adjust this code if not the case.
    STATIC_ASSERT(StackHandlerConstants::kSize == 1 * kPointerSize);
    STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
  
    // Link the current handler as the next handler.
    ExternalReference handler_address(Isolate::kHandlerAddress, isolate());
    push(Operand::StaticVariable(handler_address));
  
    // Set this new handler as the current one.
    mov(Operand::StaticVariable(handler_address), esp);
  }
  
  
  void MacroAssembler::PopStackHandler() {
    STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
    ExternalReference handler_address(Isolate::kHandlerAddress, isolate());
    pop(Operand::StaticVariable(handler_address));
    add(esp, Immediate(StackHandlerConstants::kSize - kPointerSize));
  }
  
  
  void MacroAssembler::CheckAccessGlobalProxy(Register holder_reg,
                                              Register scratch1,
                                              Register scratch2,
                                              Label* miss) {
    Label same_contexts;
  
    DCHECK(!holder_reg.is(scratch1));
    DCHECK(!holder_reg.is(scratch2));
    DCHECK(!scratch1.is(scratch2));
  
    // Load current lexical context from the stack frame.
    mov(scratch1, Operand(ebp, StandardFrameConstants::kContextOffset));
  
    // When generating debug code, make sure the lexical context is set.
    if (emit_debug_code()) {
      cmp(scratch1, Immediate(0));
      Check(not_equal, kWeShouldNotHaveAnEmptyLexicalContext);
    }
    // Load the native context of the current context.
    int offset =
        Context::kHeaderSize + Context::GLOBAL_OBJECT_INDEX * kPointerSize;
    mov(scratch1, FieldOperand(scratch1, offset));
    mov(scratch1, FieldOperand(scratch1, GlobalObject::kNativeContextOffset));
  
    // Check the context is a native context.
    if (emit_debug_code()) {
      // Read the first word and compare to native_context_map.
      cmp(FieldOperand(scratch1, HeapObject::kMapOffset),
          isolate()->factory()->native_context_map());
      Check(equal, kJSGlobalObjectNativeContextShouldBeANativeContext);
    }
  
    // Check if both contexts are the same.
    cmp(scratch1, FieldOperand(holder_reg, JSGlobalProxy::kNativeContextOffset));
    j(equal, &same_contexts);
  
    // Compare security tokens, save holder_reg on the stack so we can use it
    // as a temporary register.
    //
    // Check that the security token in the calling global object is
    // compatible with the security token in the receiving global
    // object.
    mov(scratch2,
        FieldOperand(holder_reg, JSGlobalProxy::kNativeContextOffset));
  
    // Check the context is a native context.
    if (emit_debug_code()) {
      cmp(scratch2, isolate()->factory()->null_value());
      Check(not_equal, kJSGlobalProxyContextShouldNotBeNull);
  
      // Read the first word and compare to native_context_map(),
      cmp(FieldOperand(scratch2, HeapObject::kMapOffset),
          isolate()->factory()->native_context_map());
      Check(equal, kJSGlobalObjectNativeContextShouldBeANativeContext);
    }
  
    int token_offset = Context::kHeaderSize +
                       Context::SECURITY_TOKEN_INDEX * kPointerSize;
    mov(scratch1, FieldOperand(scratch1, token_offset));
    cmp(scratch1, FieldOperand(scratch2, token_offset));
    j(not_equal, miss);
  
    bind(&same_contexts);
  }
  
  
  // Compute the hash code from the untagged key.  This must be kept in sync with
  // ComputeIntegerHash in utils.h and KeyedLoadGenericStub in
  // code-stub-hydrogen.cc
  //
  // Note: r0 will contain hash code
  void MacroAssembler::GetNumberHash(Register r0, Register scratch) {
    // Xor original key with a seed.
    if (serializer_enabled()) {
      ExternalReference roots_array_start =
          ExternalReference::roots_array_start(isolate());
      mov(scratch, Immediate(Heap::kHashSeedRootIndex));
      mov(scratch,
          Operand::StaticArray(scratch, times_pointer_size, roots_array_start));
      SmiUntag(scratch);
      xor_(r0, scratch);
    } else {
      int32_t seed = isolate()->heap()->HashSeed();
      xor_(r0, Immediate(seed));
    }
  
    // hash = ~hash + (hash << 15);
    mov(scratch, r0);
    not_(r0);
    shl(scratch, 15);
    add(r0, scratch);
    // hash = hash ^ (hash >> 12);
    mov(scratch, r0);
    shr(scratch, 12);
    xor_(r0, scratch);
    // hash = hash + (hash << 2);
    lea(r0, Operand(r0, r0, times_4, 0));
    // hash = hash ^ (hash >> 4);
    mov(scratch, r0);
    shr(scratch, 4);
    xor_(r0, scratch);
    // hash = hash * 2057;
    imul(r0, r0, 2057);
    // hash = hash ^ (hash >> 16);
    mov(scratch, r0);
    shr(scratch, 16);
    xor_(r0, scratch);
    and_(r0, 0x3fffffff);
  }
  
  
  
  void MacroAssembler::LoadFromNumberDictionary(Label* miss,
                                                Register elements,
                                                Register key,
                                                Register r0,
                                                Register r1,
                                                Register r2,
                                                Register result) {
    // Register use:
    //
    // elements - holds the slow-case elements of the receiver and is unchanged.
    //
    // key      - holds the smi key on entry and is unchanged.
    //
    // Scratch registers:
    //
    // r0 - holds the untagged key on entry and holds the hash once computed.
    //
    // r1 - used to hold the capacity mask of the dictionary
    //
    // r2 - used for the index into the dictionary.
    //
    // result - holds the result on exit if the load succeeds and we fall through.
  
    Label done;
  
    GetNumberHash(r0, r1);
  
    // Compute capacity mask.
    mov(r1, FieldOperand(elements, SeededNumberDictionary::kCapacityOffset));
    shr(r1, kSmiTagSize);  // convert smi to int
    dec(r1);
  
    // Generate an unrolled loop that performs a few probes before giving up.
    for (int i = 0; i < kNumberDictionaryProbes; i++) {
      // Use r2 for index calculations and keep the hash intact in r0.
      mov(r2, r0);
      // Compute the masked index: (hash + i + i * i) & mask.
      if (i > 0) {
        add(r2, Immediate(SeededNumberDictionary::GetProbeOffset(i)));
      }
      and_(r2, r1);
  
      // Scale the index by multiplying by the entry size.
      DCHECK(SeededNumberDictionary::kEntrySize == 3);
      lea(r2, Operand(r2, r2, times_2, 0));  // r2 = r2 * 3
  
      // Check if the key matches.
      cmp(key, FieldOperand(elements,
                            r2,
                            times_pointer_size,
                            SeededNumberDictionary::kElementsStartOffset));
      if (i != (kNumberDictionaryProbes - 1)) {
        j(equal, &done);
      } else {
        j(not_equal, miss);
      }
    }
  
    bind(&done);
    // Check that the value is a field property.
    const int kDetailsOffset =
        SeededNumberDictionary::kElementsStartOffset + 2 * kPointerSize;
    DCHECK_EQ(DATA, 0);
    test(FieldOperand(elements, r2, times_pointer_size, kDetailsOffset),
         Immediate(PropertyDetails::TypeField::kMask << kSmiTagSize));
    j(not_zero, miss);
  
    // Get the value at the masked, scaled index.
    const int kValueOffset =
        SeededNumberDictionary::kElementsStartOffset + kPointerSize;
    mov(result, FieldOperand(elements, r2, times_pointer_size, kValueOffset));
  }
  
  
  void MacroAssembler::LoadAllocationTopHelper(Register result,
                                               Register scratch,
                                               AllocationFlags flags) {
    ExternalReference allocation_top =
        AllocationUtils::GetAllocationTopReference(isolate(), flags);
  
    // Just return if allocation top is already known.
    if ((flags & RESULT_CONTAINS_TOP) != 0) {
      // No use of scratch if allocation top is provided.
      DCHECK(scratch.is(no_reg));
  #ifdef DEBUG
      // Assert that result actually contains top on entry.
      cmp(result, Operand::StaticVariable(allocation_top));
      Check(equal, kUnexpectedAllocationTop);
  #endif
      return;
    }
  
    // Move address of new object to result. Use scratch register if available.
    if (scratch.is(no_reg)) {
      mov(result, Operand::StaticVariable(allocation_top));
    } else {
      mov(scratch, Immediate(allocation_top));
      mov(result, Operand(scratch, 0));
    }
  }
  
  
  void MacroAssembler::UpdateAllocationTopHelper(Register result_end,
                                                 Register scratch,
                                                 AllocationFlags flags) {
    if (emit_debug_code()) {
      test(result_end, Immediate(kObjectAlignmentMask));
      Check(zero, kUnalignedAllocationInNewSpace);
    }
  
    ExternalReference allocation_top =
        AllocationUtils::GetAllocationTopReference(isolate(), flags);
  
    // Update new top. Use scratch if available.
    if (scratch.is(no_reg)) {
      mov(Operand::StaticVariable(allocation_top), result_end);
    } else {
      mov(Operand(scratch, 0), result_end);
    }
  }
  
  
  void MacroAssembler::Allocate(int object_size,
                                Register result,
                                Register result_end,
                                Register scratch,
                                Label* gc_required,
                                AllocationFlags flags) {
    DCHECK((flags & (RESULT_CONTAINS_TOP | SIZE_IN_WORDS)) == 0);
    DCHECK(object_size <= Page::kMaxRegularHeapObjectSize);
    if (!FLAG_inline_new) {
      if (emit_debug_code()) {
        // Trash the registers to simulate an allocation failure.
        mov(result, Immediate(0x7091));
        if (result_end.is_valid()) {
          mov(result_end, Immediate(0x7191));
        }
        if (scratch.is_valid()) {
          mov(scratch, Immediate(0x7291));
        }
      }
      jmp(gc_required);
      return;
    }
    DCHECK(!result.is(result_end));
  
    // Load address of new object into result.
    LoadAllocationTopHelper(result, scratch, flags);
  
    ExternalReference allocation_limit =
        AllocationUtils::GetAllocationLimitReference(isolate(), flags);
  
    // Align the next allocation. Storing the filler map without checking top is
    // safe in new-space because the limit of the heap is aligned there.
    if ((flags & DOUBLE_ALIGNMENT) != 0) {
      DCHECK(kPointerAlignment * 2 == kDoubleAlignment);
      Label aligned;
      test(result, Immediate(kDoubleAlignmentMask));
      j(zero, &aligned, Label::kNear);
      if ((flags & PRETENURE) != 0) {
        cmp(result, Operand::StaticVariable(allocation_limit));
        j(above_equal, gc_required);
      }
      mov(Operand(result, 0),
          Immediate(isolate()->factory()->one_pointer_filler_map()));
      add(result, Immediate(kDoubleSize / 2));
      bind(&aligned);
    }
  
    // Calculate new top and bail out if space is exhausted.
    Register top_reg = result_end.is_valid() ? result_end : result;
    if (!top_reg.is(result)) {
      mov(top_reg, result);
    }
    add(top_reg, Immediate(object_size));
    j(carry, gc_required);
    cmp(top_reg, Operand::StaticVariable(allocation_limit));
    j(above, gc_required);
  
    // Update allocation top.
    UpdateAllocationTopHelper(top_reg, scratch, flags);
  
    // Tag result if requested.
    bool tag_result = (flags & TAG_OBJECT) != 0;
    if (top_reg.is(result)) {
      if (tag_result) {
        sub(result, Immediate(object_size - kHeapObjectTag));
      } else {
        sub(result, Immediate(object_size));
      }
    } else if (tag_result) {
      DCHECK(kHeapObjectTag == 1);
      inc(result);
    }
  }
  
  
  void MacroAssembler::Allocate(int header_size,
                                ScaleFactor element_size,
                                Register element_count,
                                RegisterValueType element_count_type,
                                Register result,
                                Register result_end,
                                Register scratch,
                                Label* gc_required,
                                AllocationFlags flags) {
    DCHECK((flags & SIZE_IN_WORDS) == 0);
    if (!FLAG_inline_new) {
      if (emit_debug_code()) {
        // Trash the registers to simulate an allocation failure.
        mov(result, Immediate(0x7091));
        mov(result_end, Immediate(0x7191));
        if (scratch.is_valid()) {
          mov(scratch, Immediate(0x7291));
        }
        // Register element_count is not modified by the function.
      }
      jmp(gc_required);
      return;
    }
    DCHECK(!result.is(result_end));
  
    // Load address of new object into result.
    LoadAllocationTopHelper(result, scratch, flags);
  
    ExternalReference allocation_limit =
        AllocationUtils::GetAllocationLimitReference(isolate(), flags);
  
    // Align the next allocation. Storing the filler map without checking top is
    // safe in new-space because the limit of the heap is aligned there.
    if ((flags & DOUBLE_ALIGNMENT) != 0) {
      DCHECK(kPointerAlignment * 2 == kDoubleAlignment);
      Label aligned;
      test(result, Immediate(kDoubleAlignmentMask));
      j(zero, &aligned, Label::kNear);
      if ((flags & PRETENURE) != 0) {
        cmp(result, Operand::StaticVariable(allocation_limit));
        j(above_equal, gc_required);
      }
      mov(Operand(result, 0),
          Immediate(isolate()->factory()->one_pointer_filler_map()));
      add(result, Immediate(kDoubleSize / 2));
      bind(&aligned);
    }
  
    // Calculate new top and bail out if space is exhausted.
    // We assume that element_count*element_size + header_size does not
    // overflow.
    if (element_count_type == REGISTER_VALUE_IS_SMI) {
      STATIC_ASSERT(static_cast<ScaleFactor>(times_2 - 1) == times_1);
      STATIC_ASSERT(static_cast<ScaleFactor>(times_4 - 1) == times_2);
      STATIC_ASSERT(static_cast<ScaleFactor>(times_8 - 1) == times_4);
      DCHECK(element_size >= times_2);
      DCHECK(kSmiTagSize == 1);
      element_size = static_cast<ScaleFactor>(element_size - 1);
    } else {
      DCHECK(element_count_type == REGISTER_VALUE_IS_INT32);
    }
    lea(result_end, Operand(element_count, element_size, header_size));
    add(result_end, result);
    j(carry, gc_required);
    cmp(result_end, Operand::StaticVariable(allocation_limit));
    j(above, gc_required);
  
    if ((flags & TAG_OBJECT) != 0) {
      DCHECK(kHeapObjectTag == 1);
      inc(result);
    }
  
    // Update allocation top.
    UpdateAllocationTopHelper(result_end, scratch, flags);
  }
  
  
  void MacroAssembler::Allocate(Register object_size,
                                Register result,
                                Register result_end,
                                Register scratch,
                                Label* gc_required,
                                AllocationFlags flags) {
    DCHECK((flags & (RESULT_CONTAINS_TOP | SIZE_IN_WORDS)) == 0);
    if (!FLAG_inline_new) {
      if (emit_debug_code()) {
        // Trash the registers to simulate an allocation failure.
        mov(result, Immediate(0x7091));
        mov(result_end, Immediate(0x7191));
        if (scratch.is_valid()) {
          mov(scratch, Immediate(0x7291));
        }
        // object_size is left unchanged by this function.
      }
      jmp(gc_required);
      return;
    }
    DCHECK(!result.is(result_end));
  
    // Load address of new object into result.
    LoadAllocationTopHelper(result, scratch, flags);
  
    ExternalReference allocation_limit =
        AllocationUtils::GetAllocationLimitReference(isolate(), flags);
  
    // Align the next allocation. Storing the filler map without checking top is
    // safe in new-space because the limit of the heap is aligned there.
    if ((flags & DOUBLE_ALIGNMENT) != 0) {
      DCHECK(kPointerAlignment * 2 == kDoubleAlignment);
      Label aligned;
      test(result, Immediate(kDoubleAlignmentMask));
      j(zero, &aligned, Label::kNear);
      if ((flags & PRETENURE) != 0) {
        cmp(result, Operand::StaticVariable(allocation_limit));
        j(above_equal, gc_required);
      }
      mov(Operand(result, 0),
          Immediate(isolate()->factory()->one_pointer_filler_map()));
      add(result, Immediate(kDoubleSize / 2));
      bind(&aligned);
    }
  
    // Calculate new top and bail out if space is exhausted.
    if (!object_size.is(result_end)) {
      mov(result_end, object_size);
    }
    add(result_end, result);
    j(carry, gc_required);
    cmp(result_end, Operand::StaticVariable(allocation_limit));
    j(above, gc_required);
  
    // Tag result if requested.
    if ((flags & TAG_OBJECT) != 0) {
      DCHECK(kHeapObjectTag == 1);
      inc(result);
    }
  
    // Update allocation top.
    UpdateAllocationTopHelper(result_end, scratch, flags);
  }
  
  
  void MacroAssembler::AllocateHeapNumber(Register result,
                                          Register scratch1,
                                          Register scratch2,
                                          Label* gc_required,
                                          MutableMode mode) {
    // Allocate heap number in new space.
    Allocate(HeapNumber::kSize, result, scratch1, scratch2, gc_required,
             TAG_OBJECT);
  
    Handle<Map> map = mode == MUTABLE
        ? isolate()->factory()->mutable_heap_number_map()
        : isolate()->factory()->heap_number_map();
  
    // Set the map.
    mov(FieldOperand(result, HeapObject::kMapOffset), Immediate(map));
  }
  
  
  void MacroAssembler::AllocateTwoByteString(Register result,
                                             Register length,
                                             Register scratch1,
                                             Register scratch2,
                                             Register scratch3,
                                             Label* gc_required) {
    // Calculate the number of bytes needed for the characters in the string while
    // observing object alignment.
    DCHECK((SeqTwoByteString::kHeaderSize & kObjectAlignmentMask) == 0);
    DCHECK(kShortSize == 2);
    // scratch1 = length * 2 + kObjectAlignmentMask.
    lea(scratch1, Operand(length, length, times_1, kObjectAlignmentMask));
    and_(scratch1, Immediate(~kObjectAlignmentMask));
  
    // Allocate two byte string in new space.
    Allocate(SeqTwoByteString::kHeaderSize,
             times_1,
             scratch1,
             REGISTER_VALUE_IS_INT32,
             result,
             scratch2,
             scratch3,
             gc_required,
             TAG_OBJECT);
  
    // Set the map, length and hash field.
    mov(FieldOperand(result, HeapObject::kMapOffset),
        Immediate(isolate()->factory()->string_map()));
    mov(scratch1, length);
    SmiTag(scratch1);
    mov(FieldOperand(result, String::kLengthOffset), scratch1);
    mov(FieldOperand(result, String::kHashFieldOffset),
        Immediate(String::kEmptyHashField));
  }
  
  
  void MacroAssembler::AllocateOneByteString(Register result, Register length,
                                             Register scratch1, Register scratch2,
                                             Register scratch3,
                                             Label* gc_required) {
    // Calculate the number of bytes needed for the characters in the string while
    // observing object alignment.
    DCHECK((SeqOneByteString::kHeaderSize & kObjectAlignmentMask) == 0);
    mov(scratch1, length);
    DCHECK(kCharSize == 1);
    add(scratch1, Immediate(kObjectAlignmentMask));
    and_(scratch1, Immediate(~kObjectAlignmentMask));
  
    // Allocate one-byte string in new space.
    Allocate(SeqOneByteString::kHeaderSize,
             times_1,
             scratch1,
             REGISTER_VALUE_IS_INT32,
             result,
             scratch2,
             scratch3,
             gc_required,
             TAG_OBJECT);
  
    // Set the map, length and hash field.
    mov(FieldOperand(result, HeapObject::kMapOffset),
        Immediate(isolate()->factory()->one_byte_string_map()));
    mov(scratch1, length);
    SmiTag(scratch1);
    mov(FieldOperand(result, String::kLengthOffset), scratch1);
    mov(FieldOperand(result, String::kHashFieldOffset),
        Immediate(String::kEmptyHashField));
  }
  
  
  void MacroAssembler::AllocateOneByteString(Register result, int length,
                                             Register scratch1, Register scratch2,
                                             Label* gc_required) {
    DCHECK(length > 0);
  
    // Allocate one-byte string in new space.
    Allocate(SeqOneByteString::SizeFor(length), result, scratch1, scratch2,
             gc_required, TAG_OBJECT);
  
    // Set the map, length and hash field.
    mov(FieldOperand(result, HeapObject::kMapOffset),
        Immediate(isolate()->factory()->one_byte_string_map()));
    mov(FieldOperand(result, String::kLengthOffset),
        Immediate(Smi::FromInt(length)));
    mov(FieldOperand(result, String::kHashFieldOffset),
        Immediate(String::kEmptyHashField));
  }
  
  
  void MacroAssembler::AllocateTwoByteConsString(Register result,
                                          Register scratch1,
                                          Register scratch2,
                                          Label* gc_required) {
    // Allocate heap number in new space.
    Allocate(ConsString::kSize, result, scratch1, scratch2, gc_required,
             TAG_OBJECT);
  
    // Set the map. The other fields are left uninitialized.
    mov(FieldOperand(result, HeapObject::kMapOffset),
        Immediate(isolate()->factory()->cons_string_map()));
  }
  
  
  void MacroAssembler::AllocateOneByteConsString(Register result,
                                                 Register scratch1,
                                                 Register scratch2,
                                                 Label* gc_required) {
    Allocate(ConsString::kSize,
             result,
             scratch1,
             scratch2,
             gc_required,
             TAG_OBJECT);
  
    // Set the map. The other fields are left uninitialized.
    mov(FieldOperand(result, HeapObject::kMapOffset),
        Immediate(isolate()->factory()->cons_one_byte_string_map()));
  }
  
  
  void MacroAssembler::AllocateTwoByteSlicedString(Register result,
                                            Register scratch1,
                                            Register scratch2,
                                            Label* gc_required) {
    // Allocate heap number in new space.
    Allocate(SlicedString::kSize, result, scratch1, scratch2, gc_required,
             TAG_OBJECT);
  
    // Set the map. The other fields are left uninitialized.
    mov(FieldOperand(result, HeapObject::kMapOffset),
        Immediate(isolate()->factory()->sliced_string_map()));
  }
  
  
  void MacroAssembler::AllocateOneByteSlicedString(Register result,
                                                   Register scratch1,
                                                   Register scratch2,
                                                   Label* gc_required) {
    // Allocate heap number in new space.
    Allocate(SlicedString::kSize, result, scratch1, scratch2, gc_required,
             TAG_OBJECT);
  
    // Set the map. The other fields are left uninitialized.
    mov(FieldOperand(result, HeapObject::kMapOffset),
        Immediate(isolate()->factory()->sliced_one_byte_string_map()));
  }
  
  
  // Copy memory, byte-by-byte, from source to destination.  Not optimized for
  // long or aligned copies.  The contents of scratch and length are destroyed.
  // Source and destination are incremented by length.
  // Many variants of movsb, loop unrolling, word moves, and indexed operands
  // have been tried here already, and this is fastest.
  // A simpler loop is faster on small copies, but 30% slower on large ones.
  // The cld() instruction must have been emitted, to set the direction flag(),
  // before calling this function.
  void MacroAssembler::CopyBytes(Register source,
                                 Register destination,
                                 Register length,
                                 Register scratch) {
    Label short_loop, len4, len8, len12, done, short_string;
    DCHECK(source.is(esi));
    DCHECK(destination.is(edi));
    DCHECK(length.is(ecx));
    cmp(length, Immediate(4));
    j(below, &short_string, Label::kNear);
  
    // Because source is 4-byte aligned in our uses of this function,
    // we keep source aligned for the rep_movs call by copying the odd bytes
    // at the end of the ranges.
    mov(scratch, Operand(source, length, times_1, -4));
    mov(Operand(destination, length, times_1, -4), scratch);
  
    cmp(length, Immediate(8));
    j(below_equal, &len4, Label::kNear);
    cmp(length, Immediate(12));
    j(below_equal, &len8, Label::kNear);
    cmp(length, Immediate(16));
    j(below_equal, &len12, Label::kNear);
  
    mov(scratch, ecx);
    shr(ecx, 2);
    rep_movs();
    and_(scratch, Immediate(0x3));
    add(destination, scratch);
    jmp(&done, Label::kNear);
  
    bind(&len12);
    mov(scratch, Operand(source, 8));
    mov(Operand(destination, 8), scratch);
    bind(&len8);
    mov(scratch, Operand(source, 4));
    mov(Operand(destination, 4), scratch);
    bind(&len4);
    mov(scratch, Operand(source, 0));
    mov(Operand(destination, 0), scratch);
    add(destination, length);
    jmp(&done, Label::kNear);
  
    bind(&short_string);
    test(length, length);
    j(zero, &done, Label::kNear);
  
    bind(&short_loop);
    mov_b(scratch, Operand(source, 0));
    mov_b(Operand(destination, 0), scratch);
    inc(source);
    inc(destination);
    dec(length);
    j(not_zero, &short_loop);
  
    bind(&done);
  }
  
  
  void MacroAssembler::InitializeFieldsWithFiller(Register start_offset,
                                                  Register end_offset,
                                                  Register filler) {
    Label loop, entry;
    jmp(&entry);
    bind(&loop);
    mov(Operand(start_offset, 0), filler);
    add(start_offset, Immediate(kPointerSize));
    bind(&entry);
    cmp(start_offset, end_offset);
    j(below, &loop);
  }
  
  
  void MacroAssembler::BooleanBitTest(Register object,
                                      int field_offset,
                                      int bit_index) {
    bit_index += kSmiTagSize + kSmiShiftSize;
    DCHECK(base::bits::IsPowerOfTwo32(kBitsPerByte));
    int byte_index = bit_index / kBitsPerByte;
    int byte_bit_index = bit_index & (kBitsPerByte - 1);
    test_b(FieldOperand(object, field_offset + byte_index),
           static_cast<byte>(1 << byte_bit_index));
  }
  
  
  
  void MacroAssembler::NegativeZeroTest(Register result,
                                        Register op,
                                        Label* then_label) {
    Label ok;
    test(result, result);
    j(not_zero, &ok);
    test(op, op);
    j(sign, then_label);
    bind(&ok);
  }
  
  
  void MacroAssembler::NegativeZeroTest(Register result,
                                        Register op1,
                                        Register op2,
                                        Register scratch,
                                        Label* then_label) {
    Label ok;
    test(result, result);
    j(not_zero, &ok);
    mov(scratch, op1);
    or_(scratch, op2);
    j(sign, then_label);
    bind(&ok);
  }
  
  
  void MacroAssembler::GetMapConstructor(Register result, Register map,
                                         Register temp) {
    Label done, loop;
    mov(result, FieldOperand(map, Map::kConstructorOrBackPointerOffset));
    bind(&loop);
    JumpIfSmi(result, &done, Label::kNear);
    CmpObjectType(result, MAP_TYPE, temp);
    j(not_equal, &done, Label::kNear);
    mov(result, FieldOperand(result, Map::kConstructorOrBackPointerOffset));
    jmp(&loop);
    bind(&done);
  }
  
  
  void MacroAssembler::TryGetFunctionPrototype(Register function, Register result,
                                               Register scratch, Label* miss) {
    // 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(result, Immediate(isolate()->factory()->the_hole_value()));
    j(equal, miss);
  
    // If the function does not have an initial map, we're done.
    Label done;
    CmpObjectType(result, MAP_TYPE, scratch);
    j(not_equal, &done, Label::kNear);
  
    // Get the prototype from the initial map.
    mov(result, FieldOperand(result, Map::kPrototypeOffset));
  
    // All done.
    bind(&done);
  }
  
  
  void MacroAssembler::CallStub(CodeStub* stub, TypeFeedbackId ast_id) {
    DCHECK(AllowThisStubCall(stub));  // Calls are not allowed in some stubs.
    call(stub->GetCode(), RelocInfo::CODE_TARGET, ast_id);
  }
  
  
  void MacroAssembler::TailCallStub(CodeStub* stub) {
    jmp(stub->GetCode(), RelocInfo::CODE_TARGET);
  }
  
  
  void MacroAssembler::StubReturn(int argc) {
    DCHECK(argc >= 1 && generating_stub());
    ret((argc - 1) * kPointerSize);
  }
  
  
  bool MacroAssembler::AllowThisStubCall(CodeStub* stub) {
    return has_frame_ || !stub->SometimesSetsUpAFrame();
  }
  
  
  void MacroAssembler::IndexFromHash(Register hash, Register index) {
    // The assert checks that the constants for the maximum number of digits
    // for an array index cached in the hash field and the number of bits
    // reserved for it does not conflict.
    DCHECK(TenToThe(String::kMaxCachedArrayIndexLength) <
           (1 << String::kArrayIndexValueBits));
    if (!index.is(hash)) {
      mov(index, hash);
    }
    DecodeFieldToSmi<String::ArrayIndexValueBits>(index);
  }
  
  
  void MacroAssembler::CallRuntime(const Runtime::Function* f, int num_arguments,
                                   SaveFPRegsMode save_doubles) {
    // If the expected number of arguments of the runtime function is
    // constant, we check that the actual number of arguments match the
    // expectation.
    CHECK(f->nargs < 0 || f->nargs == num_arguments);
  
    // 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.
    Move(eax, Immediate(num_arguments));
    mov(ebx, Immediate(ExternalReference(f, isolate())));
    CEntryStub ces(isolate(), 1, save_doubles);
    CallStub(&ces);
  }
  
  
  void MacroAssembler::CallExternalReference(ExternalReference ref,
                                             int num_arguments) {
    mov(eax, Immediate(num_arguments));
    mov(ebx, Immediate(ref));
  
    CEntryStub stub(isolate(), 1);
    CallStub(&stub);
  }
  
  
  void MacroAssembler::TailCallExternalReference(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.
    Move(eax, Immediate(num_arguments));
    JumpToExternalReference(ext);
  }
  
  
  void MacroAssembler::TailCallRuntime(Runtime::FunctionId fid,
                                       int num_arguments,
                                       int result_size) {
    TailCallExternalReference(ExternalReference(fid, isolate()),
                              num_arguments,
                              result_size);
  }
  
  
  void MacroAssembler::JumpToExternalReference(const ExternalReference& ext) {
    // Set the entry point and jump to the C entry runtime stub.
    mov(ebx, Immediate(ext));
    CEntryStub ces(isolate(), 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,
                                      bool* definitely_mismatches,
                                      InvokeFlag flag,
                                      Label::Distance done_near,
                                      const CallWrapper& call_wrapper) {
    bool definitely_matches = false;
    *definitely_mismatches = false;
    Label invoke;
    if (expected.is_immediate()) {
      DCHECK(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 {
          *definitely_mismatches = true;
          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);
        DCHECK(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(), actual.reg());
        j(equal, &invoke);
        DCHECK(actual.reg().is(eax));
        DCHECK(expected.reg().is(ebx));
      }
    }
  
    if (!definitely_matches) {
      Handle<Code> adaptor =
          isolate()->builtins()->ArgumentsAdaptorTrampoline();
      if (!code_constant.is_null()) {
        mov(edx, Immediate(code_constant));
        add(edx, Immediate(Code::kHeaderSize - kHeapObjectTag));
      } else if (!code_operand.is_reg(edx)) {
        mov(edx, code_operand);
      }
  
      if (flag == CALL_FUNCTION) {
        call_wrapper.BeforeCall(CallSize(adaptor, RelocInfo::CODE_TARGET));
        call(adaptor, RelocInfo::CODE_TARGET);
        call_wrapper.AfterCall();
        if (!*definitely_mismatches) {
          jmp(done, done_near);
        }
      } else {
        jmp(adaptor, RelocInfo::CODE_TARGET);
      }
      bind(&invoke);
    }
  }
  
  
  void MacroAssembler::InvokeCode(const Operand& code,
                                  const ParameterCount& expected,
                                  const ParameterCount& actual,
                                  InvokeFlag flag,
                                  const CallWrapper& call_wrapper) {
    // You can't call a function without a valid frame.
    DCHECK(flag == JUMP_FUNCTION || has_frame());
  
    Label done;
    bool definitely_mismatches = false;
    InvokePrologue(expected, actual, Handle<Code>::null(), code,
                   &done, &definitely_mismatches, flag, Label::kNear,
                   call_wrapper);
    if (!definitely_mismatches) {
      if (flag == CALL_FUNCTION) {
        call_wrapper.BeforeCall(CallSize(code));
        call(code);
        call_wrapper.AfterCall();
      } else {
        DCHECK(flag == JUMP_FUNCTION);
        jmp(code);
      }
      bind(&done);
    }
  }
  
  
  void MacroAssembler::InvokeFunction(Register fun,
                                      const ParameterCount& actual,
                                      InvokeFlag flag,
                                      const CallWrapper& call_wrapper) {
    // You can't call a function without a valid frame.
    DCHECK(flag == JUMP_FUNCTION || has_frame());
  
    DCHECK(fun.is(edi));
    mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
    mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
    mov(ebx, FieldOperand(edx, SharedFunctionInfo::kFormalParameterCountOffset));
    SmiUntag(ebx);
  
    ParameterCount expected(ebx);
    InvokeCode(FieldOperand(edi, JSFunction::kCodeEntryOffset),
               expected, actual, flag, call_wrapper);
  }
  
  
  void MacroAssembler::InvokeFunction(Register fun,
                                      const ParameterCount& expected,
                                      const ParameterCount& actual,
                                      InvokeFlag flag,
                                      const CallWrapper& call_wrapper) {
    // You can't call a function without a valid frame.
    DCHECK(flag == JUMP_FUNCTION || has_frame());
  
    DCHECK(fun.is(edi));
    mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
  
    InvokeCode(FieldOperand(edi, JSFunction::kCodeEntryOffset),
               expected, actual, flag, call_wrapper);
  }
  
  
  void MacroAssembler::InvokeFunction(Handle<JSFunction> function,
                                      const ParameterCount& expected,
                                      const ParameterCount& actual,
                                      InvokeFlag flag,
                                      const CallWrapper& call_wrapper) {
    LoadHeapObject(edi, function);
    InvokeFunction(edi, expected, actual, flag, call_wrapper);
  }
  
  
  void MacroAssembler::InvokeBuiltin(int native_context_index, InvokeFlag flag,
                                     const CallWrapper& call_wrapper) {
    // You can't call a builtin without a valid frame.
    DCHECK(flag == JUMP_FUNCTION || has_frame());
  
    // 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);
    GetBuiltinFunction(edi, native_context_index);
    InvokeCode(FieldOperand(edi, JSFunction::kCodeEntryOffset),
               expected, expected, flag, call_wrapper);
  }
  
  
  void MacroAssembler::GetBuiltinFunction(Register target,
                                          int native_context_index) {
    // Load the JavaScript builtin function from the builtins object.
    mov(target, Operand(esi, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
    mov(target, FieldOperand(target, GlobalObject::kNativeContextOffset));
    mov(target, ContextOperand(target, native_context_index));
  }
  
  
  void MacroAssembler::GetBuiltinEntry(Register target,
                                       int native_context_index) {
    DCHECK(!target.is(edi));
    // Load the JavaScript builtin function from the builtins object.
    GetBuiltinFunction(edi, native_context_index);
    // Load the code entry point from the function into the target register.
    mov(target, FieldOperand(edi, JSFunction::kCodeEntryOffset));
  }
  
  
  void MacroAssembler::LoadContext(Register dst, int context_chain_length) {
    if (context_chain_length > 0) {
      // Move up the chain of contexts to the context containing the slot.
      mov(dst, Operand(esi, Context::SlotOffset(Context::PREVIOUS_INDEX)));
      for (int i = 1; i < context_chain_length; i++) {
        mov(dst, Operand(dst, Context::SlotOffset(Context::PREVIOUS_INDEX)));
      }
    } else {
      // Slot is in the current function context.  Move it into the
      // destination register in case we store into it (the write barrier
      // cannot be allowed to destroy the context in esi).
      mov(dst, esi);
    }
  
    // We should not have found a with context by walking the context chain
    // (i.e., the static scope chain and runtime context chain do not agree).
    // A variable occurring in such a scope should have slot type LOOKUP and
    // not CONTEXT.
    if (emit_debug_code()) {
      cmp(FieldOperand(dst, HeapObject::kMapOffset),
          isolate()->factory()->with_context_map());
      Check(not_equal, kVariableResolvedToWithContext);
    }
  }
  
  
  void MacroAssembler::LoadTransitionedArrayMapConditional(
      ElementsKind expected_kind,
      ElementsKind transitioned_kind,
      Register map_in_out,
      Register scratch,
      Label* no_map_match) {
    // Load the global or builtins object from the current context.
    mov(scratch, Operand(esi, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
    mov(scratch, FieldOperand(scratch, GlobalObject::kNativeContextOffset));
  
    // Check that the function's map is the same as the expected cached map.
    mov(scratch, Operand(scratch,
                         Context::SlotOffset(Context::JS_ARRAY_MAPS_INDEX)));
  
    size_t offset = expected_kind * kPointerSize +
        FixedArrayBase::kHeaderSize;
    cmp(map_in_out, FieldOperand(scratch, offset));
    j(not_equal, no_map_match);
  
    // Use the transitioned cached map.
    offset = transitioned_kind * kPointerSize +
        FixedArrayBase::kHeaderSize;
    mov(map_in_out, FieldOperand(scratch, offset));
  }
  
  
  void MacroAssembler::LoadGlobalFunction(int index, Register function) {
    // Load the global or builtins object from the current context.
    mov(function,
        Operand(esi, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
    // Load the native context from the global or builtins object.
    mov(function,
        FieldOperand(function, GlobalObject::kNativeContextOffset));
    // Load the function from the native context.
    mov(function, Operand(function, Context::SlotOffset(index)));
  }
  
  
  void MacroAssembler::LoadGlobalFunctionInitialMap(Register function,
                                                    Register map) {
    // Load the initial map.  The global functions all have initial maps.
    mov(map, FieldOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
    if (emit_debug_code()) {
      Label ok, fail;
      CheckMap(map, isolate()->factory()->meta_map(), &fail, DO_SMI_CHECK);
      jmp(&ok);
      bind(&fail);
      Abort(kGlobalFunctionsMustHaveInitialMap);
      bind(&ok);
    }
  }
  
  
  // Store the value in register src in the safepoint register stack
  // slot for register dst.
  void MacroAssembler::StoreToSafepointRegisterSlot(Register dst, Register src) {
    mov(SafepointRegisterSlot(dst), src);
  }
  
  
  void MacroAssembler::StoreToSafepointRegisterSlot(Register dst, Immediate src) {
    mov(SafepointRegisterSlot(dst), src);
  }
  
  
  void MacroAssembler::LoadFromSafepointRegisterSlot(Register dst, Register src) {
    mov(dst, SafepointRegisterSlot(src));
  }
  
  
  Operand MacroAssembler::SafepointRegisterSlot(Register reg) {
    return Operand(esp, SafepointRegisterStackIndex(reg.code()) * kPointerSize);
  }
  
  
  int MacroAssembler::SafepointRegisterStackIndex(int reg_code) {
    // The registers are pushed starting with the lowest encoding,
    // which means that lowest encodings are furthest away from
    // the stack pointer.
    DCHECK(reg_code >= 0 && reg_code < kNumSafepointRegisters);
    return kNumSafepointRegisters - reg_code - 1;
  }
  
  
  void MacroAssembler::LoadHeapObject(Register result,
                                      Handle<HeapObject> object) {
    AllowDeferredHandleDereference embedding_raw_address;
    if (isolate()->heap()->InNewSpace(*object)) {
      Handle<Cell> cell = isolate()->factory()->NewCell(object);
      mov(result, Operand::ForCell(cell));
    } else {
      mov(result, object);
    }
  }
  
  
  void MacroAssembler::CmpHeapObject(Register reg, Handle<HeapObject> object) {
    AllowDeferredHandleDereference using_raw_address;
    if (isolate()->heap()->InNewSpace(*object)) {
      Handle<Cell> cell = isolate()->factory()->NewCell(object);
      cmp(reg, Operand::ForCell(cell));
    } else {
      cmp(reg, object);
    }
  }
  
  
  void MacroAssembler::PushHeapObject(Handle<HeapObject> object) {
    AllowDeferredHandleDereference using_raw_address;
    if (isolate()->heap()->InNewSpace(*object)) {
      Handle<Cell> cell = isolate()->factory()->NewCell(object);
      push(Operand::ForCell(cell));
    } else {
      Push(object);
    }
  }
  
  
  void MacroAssembler::CmpWeakValue(Register value, Handle<WeakCell> cell,
                                    Register scratch) {
    mov(scratch, cell);
    cmp(value, FieldOperand(scratch, WeakCell::kValueOffset));
  }
  
  
  void MacroAssembler::GetWeakValue(Register value, Handle<WeakCell> cell) {
    mov(value, cell);
    mov(value, FieldOperand(value, WeakCell::kValueOffset));
  }
  
  
  void MacroAssembler::LoadWeakValue(Register value, Handle<WeakCell> cell,
                                     Label* miss) {
    GetWeakValue(value, cell);
    JumpIfSmi(value, miss);
  }
  
  
  void MacroAssembler::Ret() {
    ret(0);
  }
  
  
  void MacroAssembler::Ret(int bytes_dropped, Register scratch) {
    if (is_uint16(bytes_dropped)) {
      ret(bytes_dropped);
    } else {
      pop(scratch);
      add(esp, Immediate(bytes_dropped));
      push(scratch);
      ret(0);
    }
  }
  
  
  void MacroAssembler::VerifyX87StackDepth(uint32_t depth) {
    // Turn off the stack depth check when serializer is enabled to reduce the
    // code size.
    if (serializer_enabled()) return;
    // Make sure the floating point stack is either empty or has depth items.
    DCHECK(depth <= 7);
    // This is very expensive.
    DCHECK(FLAG_debug_code && FLAG_enable_slow_asserts);
  
    // The top-of-stack (tos) is 7 if there is one item pushed.
    int tos = (8 - depth) % 8;
    const int kTopMask = 0x3800;
    push(eax);
    fwait();
    fnstsw_ax();
    and_(eax, kTopMask);
    shr(eax, 11);
    cmp(eax, Immediate(tos));
    Check(equal, kUnexpectedFPUStackDepthAfterInstruction);
    fnclex();
    pop(eax);
  }
  
  
  void MacroAssembler::Drop(int stack_elements) {
    if (stack_elements > 0) {
      add(esp, Immediate(stack_elements * kPointerSize));
    }
  }
  
  
  void MacroAssembler::Move(Register dst, Register src) {
    if (!dst.is(src)) {
      mov(dst, src);
    }
  }
  
  
  void MacroAssembler::Move(Register dst, const Immediate& x) {
    if (x.is_zero()) {
      xor_(dst, dst);  // Shorter than mov of 32-bit immediate 0.
    } else {
      mov(dst, x);
    }
  }
  
  
  void MacroAssembler::Move(const Operand& dst, const Immediate& x) {
    mov(dst, x);
  }
  
  
  void MacroAssembler::Lzcnt(Register dst, const Operand& src) {
    // TODO(intel): Add support for LZCNT (with ABM/BMI1).
    Label not_zero_src;
    bsr(dst, src);
    j(not_zero, &not_zero_src, Label::kNear);
    Move(dst, Immediate(63));  // 63^31 == 32
    bind(&not_zero_src);
    xor_(dst, Immediate(31));  // for x in [0..31], 31^x == 31-x.
  }
  
  
  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) {
    DCHECK(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) {
    DCHECK(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::IncrementCounter(Condition cc,
                                        StatsCounter* counter,
                                        int value) {
    DCHECK(value > 0);
    if (FLAG_native_code_counters && counter->Enabled()) {
      Label skip;
      j(NegateCondition(cc), &skip);
      pushfd();
      IncrementCounter(counter, value);
      popfd();
      bind(&skip);
    }
  }
  
  
  void MacroAssembler::DecrementCounter(Condition cc,
                                        StatsCounter* counter,
                                        int value) {
    DCHECK(value > 0);
    if (FLAG_native_code_counters && counter->Enabled()) {
      Label skip;
      j(NegateCondition(cc), &skip);
      pushfd();
      DecrementCounter(counter, value);
      popfd();
      bind(&skip);
    }
  }
  
  
  void MacroAssembler::Assert(Condition cc, BailoutReason reason) {
    if (emit_debug_code()) Check(cc, reason);
  }
  
  
  void MacroAssembler::AssertFastElements(Register elements) {
    if (emit_debug_code()) {
      Factory* factory = isolate()->factory();
      Label ok;
      cmp(FieldOperand(elements, HeapObject::kMapOffset),
          Immediate(factory->fixed_array_map()));
      j(equal, &ok);
      cmp(FieldOperand(elements, HeapObject::kMapOffset),
          Immediate(factory->fixed_double_array_map()));
      j(equal, &ok);
      cmp(FieldOperand(elements, HeapObject::kMapOffset),
          Immediate(factory->fixed_cow_array_map()));
      j(equal, &ok);
      Abort(kJSObjectWithFastElementsMapHasSlowElements);
      bind(&ok);
    }
  }
  
  
  void MacroAssembler::Check(Condition cc, BailoutReason reason) {
    Label L;
    j(cc, &L);
    Abort(reason);
    // will not return here
    bind(&L);
  }
  
  
  void MacroAssembler::CheckStackAlignment() {
    int frame_alignment = base::OS::ActivationFrameAlignment();
    int frame_alignment_mask = frame_alignment - 1;
    if (frame_alignment > kPointerSize) {
      DCHECK(base::bits::IsPowerOfTwo32(frame_alignment));
      Label alignment_as_expected;
      test(esp, Immediate(frame_alignment_mask));
      j(zero, &alignment_as_expected);
      // Abort if stack is not aligned.
      int3();
      bind(&alignment_as_expected);
    }
  }
  
  
  void MacroAssembler::Abort(BailoutReason reason) {
  #ifdef DEBUG
    const char* msg = GetBailoutReason(reason);
    if (msg != NULL) {
      RecordComment("Abort message: ");
      RecordComment(msg);
    }
  
    if (FLAG_trap_on_abort) {
      int3();
      return;
    }
  #endif
  
    push(Immediate(reinterpret_cast<intptr_t>(Smi::FromInt(reason))));
    // Disable stub call restrictions to always allow calls to abort.
    if (!has_frame_) {
      // We don't actually want to generate a pile of code for this, so just
      // claim there is a stack frame, without generating one.
      FrameScope scope(this, StackFrame::NONE);
      CallRuntime(Runtime::kAbort, 1);
    } else {
      CallRuntime(Runtime::kAbort, 1);
    }
    // will not return here
    int3();
  }
  
  
  void MacroAssembler::LoadInstanceDescriptors(Register map,
                                               Register descriptors) {
    mov(descriptors, FieldOperand(map, Map::kDescriptorsOffset));
  }
  
  
  void MacroAssembler::NumberOfOwnDescriptors(Register dst, Register map) {
    mov(dst, FieldOperand(map, Map::kBitField3Offset));
    DecodeField<Map::NumberOfOwnDescriptorsBits>(dst);
  }
  
  
  void MacroAssembler::LoadAccessor(Register dst, Register holder,
                                    int accessor_index,
                                    AccessorComponent accessor) {
    mov(dst, FieldOperand(holder, HeapObject::kMapOffset));
    LoadInstanceDescriptors(dst, dst);
    mov(dst, FieldOperand(dst, DescriptorArray::GetValueOffset(accessor_index)));
    int offset = accessor == ACCESSOR_GETTER ? AccessorPair::kGetterOffset
                                             : AccessorPair::kSetterOffset;
    mov(dst, FieldOperand(dst, offset));
  }
  
  
  void MacroAssembler::LookupNumberStringCache(Register object,
                                               Register result,
                                               Register scratch1,
                                               Register scratch2,
                                               Label* not_found) {
    // Use of registers. Register result is used as a temporary.
    Register number_string_cache = result;
    Register mask = scratch1;
    Register scratch = scratch2;
  
    // Load the number string cache.
    LoadRoot(number_string_cache, Heap::kNumberStringCacheRootIndex);
    // Make the hash mask from the length of the number string cache. It
    // contains two elements (number and string) for each cache entry.
    mov(mask, FieldOperand(number_string_cache, FixedArray::kLengthOffset));
    shr(mask, kSmiTagSize + 1);  // Untag length and divide it by two.
    sub(mask, Immediate(1));  // Make mask.
  
    // Calculate the entry in the number string cache. The hash value in the
    // number string cache for smis is just the smi value, and the hash for
    // doubles is the xor of the upper and lower words. See
    // Heap::GetNumberStringCache.
    Label smi_hash_calculated;
    Label load_result_from_cache;
    Label not_smi;
    STATIC_ASSERT(kSmiTag == 0);
    JumpIfNotSmi(object, &not_smi, Label::kNear);
    mov(scratch, object);
    SmiUntag(scratch);
    jmp(&smi_hash_calculated, Label::kNear);
    bind(&not_smi);
    cmp(FieldOperand(object, HeapObject::kMapOffset),
        isolate()->factory()->heap_number_map());
    j(not_equal, not_found);
    STATIC_ASSERT(8 == kDoubleSize);
    mov(scratch, FieldOperand(object, HeapNumber::kValueOffset));
    xor_(scratch, FieldOperand(object, HeapNumber::kValueOffset + 4));
    // Object is heap number and hash is now in scratch. Calculate cache index.
    and_(scratch, mask);
    Register index = scratch;
    Register probe = mask;
    mov(probe,
        FieldOperand(number_string_cache,
                     index,
                     times_twice_pointer_size,
                     FixedArray::kHeaderSize));
    JumpIfSmi(probe, not_found);
    fld_d(FieldOperand(object, HeapNumber::kValueOffset));
    fld_d(FieldOperand(probe, HeapNumber::kValueOffset));
    FCmp();
    j(parity_even, not_found);  // Bail out if NaN is involved.
    j(not_equal, not_found);  // The cache did not contain this value.
    jmp(&load_result_from_cache, Label::kNear);
  
    bind(&smi_hash_calculated);
    // Object is smi and hash is now in scratch. Calculate cache index.
    and_(scratch, mask);
    // Check if the entry is the smi we are looking for.
    cmp(object,
        FieldOperand(number_string_cache,
                     index,
                     times_twice_pointer_size,
                     FixedArray::kHeaderSize));
    j(not_equal, not_found);
  
    // Get the result from the cache.
    bind(&load_result_from_cache);
    mov(result,
        FieldOperand(number_string_cache,
                     index,
                     times_twice_pointer_size,
                     FixedArray::kHeaderSize + kPointerSize));
    IncrementCounter(isolate()->counters()->number_to_string_native(), 1);
  }
  
  
  void MacroAssembler::JumpIfInstanceTypeIsNotSequentialOneByte(
      Register instance_type, Register scratch, Label* failure) {
    if (!scratch.is(instance_type)) {
      mov(scratch, instance_type);
    }
    and_(scratch,
         kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask);
    cmp(scratch, kStringTag | kSeqStringTag | kOneByteStringTag);
    j(not_equal, failure);
  }
  
  
  void MacroAssembler::JumpIfNotBothSequentialOneByteStrings(Register object1,
                                                             Register object2,
                                                             Register scratch1,
                                                             Register scratch2,
                                                             Label* failure) {
    // Check that both objects are not smis.
    STATIC_ASSERT(kSmiTag == 0);
    mov(scratch1, object1);
    and_(scratch1, object2);
    JumpIfSmi(scratch1, failure);
  
    // Load instance type for both strings.
    mov(scratch1, FieldOperand(object1, HeapObject::kMapOffset));
    mov(scratch2, FieldOperand(object2, HeapObject::kMapOffset));
    movzx_b(scratch1, FieldOperand(scratch1, Map::kInstanceTypeOffset));
    movzx_b(scratch2, FieldOperand(scratch2, Map::kInstanceTypeOffset));
  
    // Check that both are flat one-byte strings.
    const int kFlatOneByteStringMask =
        kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask;
    const int kFlatOneByteStringTag =
        kStringTag | kOneByteStringTag | kSeqStringTag;
    // Interleave bits from both instance types and compare them in one check.
    DCHECK_EQ(0, kFlatOneByteStringMask & (kFlatOneByteStringMask << 3));
    and_(scratch1, kFlatOneByteStringMask);
    and_(scratch2, kFlatOneByteStringMask);
    lea(scratch1, Operand(scratch1, scratch2, times_8, 0));
    cmp(scratch1, kFlatOneByteStringTag | (kFlatOneByteStringTag << 3));
    j(not_equal, failure);
  }
  
  
  void MacroAssembler::JumpIfNotUniqueNameInstanceType(Operand operand,
                                                       Label* not_unique_name,
                                                       Label::Distance distance) {
    STATIC_ASSERT(kInternalizedTag == 0 && kStringTag == 0);
    Label succeed;
    test(operand, Immediate(kIsNotStringMask | kIsNotInternalizedMask));
    j(zero, &succeed);
    cmpb(operand, static_cast<uint8_t>(SYMBOL_TYPE));
    j(not_equal, not_unique_name, distance);
  
    bind(&succeed);
  }
  
  
  void MacroAssembler::EmitSeqStringSetCharCheck(Register string,
                                                 Register index,
                                                 Register value,
                                                 uint32_t encoding_mask) {
    Label is_object;
    JumpIfNotSmi(string, &is_object, Label::kNear);
    Abort(kNonObject);
    bind(&is_object);
  
    push(value);
    mov(value, FieldOperand(string, HeapObject::kMapOffset));
    movzx_b(value, FieldOperand(value, Map::kInstanceTypeOffset));
  
    and_(value, Immediate(kStringRepresentationMask | kStringEncodingMask));
    cmp(value, Immediate(encoding_mask));
    pop(value);
    Check(equal, kUnexpectedStringType);
  
    // The index is assumed to be untagged coming in, tag it to compare with the
    // string length without using a temp register, it is restored at the end of
    // this function.
    SmiTag(index);
    Check(no_overflow, kIndexIsTooLarge);
  
    cmp(index, FieldOperand(string, String::kLengthOffset));
    Check(less, kIndexIsTooLarge);
  
    cmp(index, Immediate(Smi::FromInt(0)));
    Check(greater_equal, kIndexIsNegative);
  
    // Restore the index
    SmiUntag(index);
  }
  
  
  void MacroAssembler::PrepareCallCFunction(int num_arguments, Register scratch) {
    int frame_alignment = base::OS::ActivationFrameAlignment();
    if (frame_alignment != 0) {
      // Make stack end at alignment and make room for num_arguments words
      // and the original value of esp.
      mov(scratch, esp);
      sub(esp, Immediate((num_arguments + 1) * kPointerSize));
      DCHECK(base::bits::IsPowerOfTwo32(frame_alignment));
      and_(esp, -frame_alignment);
      mov(Operand(esp, num_arguments * kPointerSize), scratch);
    } else {
      sub(esp, Immediate(num_arguments * kPointerSize));
    }
  }
  
  
  void MacroAssembler::CallCFunction(ExternalReference function,
                                     int num_arguments) {
    // Trashing eax is ok as it will be the return value.
    mov(eax, Immediate(function));
    CallCFunction(eax, num_arguments);
  }
  
  
  void MacroAssembler::CallCFunction(Register function,
                                     int num_arguments) {
    DCHECK(has_frame());
    // Check stack alignment.
    if (emit_debug_code()) {
      CheckStackAlignment();
    }
  
    call(function);
    if (base::OS::ActivationFrameAlignment() != 0) {
      mov(esp, Operand(esp, num_arguments * kPointerSize));
    } else {
      add(esp, Immediate(num_arguments * kPointerSize));
    }
  }
  
  
  #ifdef DEBUG
  bool AreAliased(Register reg1,
                  Register reg2,
                  Register reg3,
                  Register reg4,
                  Register reg5,
                  Register reg6,
                  Register reg7,
                  Register reg8) {
    int n_of_valid_regs = reg1.is_valid() + reg2.is_valid() +
        reg3.is_valid() + reg4.is_valid() + reg5.is_valid() + reg6.is_valid() +
        reg7.is_valid() + reg8.is_valid();
  
    RegList regs = 0;
    if (reg1.is_valid()) regs |= reg1.bit();
    if (reg2.is_valid()) regs |= reg2.bit();
    if (reg3.is_valid()) regs |= reg3.bit();
    if (reg4.is_valid()) regs |= reg4.bit();
    if (reg5.is_valid()) regs |= reg5.bit();
    if (reg6.is_valid()) regs |= reg6.bit();
    if (reg7.is_valid()) regs |= reg7.bit();
    if (reg8.is_valid()) regs |= reg8.bit();
    int n_of_non_aliasing_regs = NumRegs(regs);
  
    return n_of_valid_regs != n_of_non_aliasing_regs;
  }
  #endif
  
  
  CodePatcher::CodePatcher(byte* address, int size)
      : address_(address),
        size_(size),
        masm_(NULL, 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.
    DCHECK(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
  }
  
  
  CodePatcher::~CodePatcher() {
    // Indicate that code has changed.
    CpuFeatures::FlushICache(address_, size_);
  
    // Check that the code was patched as expected.
    DCHECK(masm_.pc_ == address_ + size_);
    DCHECK(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
  }
  
  
  void MacroAssembler::CheckPageFlag(
      Register object,
      Register scratch,
      int mask,
      Condition cc,
      Label* condition_met,
      Label::Distance condition_met_distance) {
    DCHECK(cc == zero || cc == not_zero);
    if (scratch.is(object)) {
      and_(scratch, Immediate(~Page::kPageAlignmentMask));
    } else {
      mov(scratch, Immediate(~Page::kPageAlignmentMask));
      and_(scratch, object);
    }
    if (mask < (1 << kBitsPerByte)) {
      test_b(Operand(scratch, MemoryChunk::kFlagsOffset),
             static_cast<uint8_t>(mask));
    } else {
      test(Operand(scratch, MemoryChunk::kFlagsOffset), Immediate(mask));
    }
    j(cc, condition_met, condition_met_distance);
  }
  
  
  void MacroAssembler::CheckPageFlagForMap(
      Handle<Map> map,
      int mask,
      Condition cc,
      Label* condition_met,
      Label::Distance condition_met_distance) {
    DCHECK(cc == zero || cc == not_zero);
    Page* page = Page::FromAddress(map->address());
    DCHECK(!serializer_enabled());  // Serializer cannot match page_flags.
    ExternalReference reference(ExternalReference::page_flags(page));
    // The inlined static address check of the page's flags relies
    // on maps never being compacted.
    DCHECK(!isolate()->heap()->mark_compact_collector()->
           IsOnEvacuationCandidate(*map));
    if (mask < (1 << kBitsPerByte)) {
      test_b(Operand::StaticVariable(reference), static_cast<uint8_t>(mask));
    } else {
      test(Operand::StaticVariable(reference), Immediate(mask));
    }
    j(cc, condition_met, condition_met_distance);
  }
  
  
  void MacroAssembler::JumpIfBlack(Register object,
                                   Register scratch0,
                                   Register scratch1,
                                   Label* on_black,
                                   Label::Distance on_black_near) {
    HasColor(object, scratch0, scratch1,
             on_black, on_black_near,
             1, 0);  // kBlackBitPattern.
    DCHECK(strcmp(Marking::kBlackBitPattern, "10") == 0);
  }
  
  
  void MacroAssembler::HasColor(Register object,
                                Register bitmap_scratch,
                                Register mask_scratch,
                                Label* has_color,
                                Label::Distance has_color_distance,
                                int first_bit,
                                int second_bit) {
    DCHECK(!AreAliased(object, bitmap_scratch, mask_scratch, ecx));
  
    GetMarkBits(object, bitmap_scratch, mask_scratch);
  
    Label other_color, word_boundary;
    test(mask_scratch, Operand(bitmap_scratch, MemoryChunk::kHeaderSize));
    j(first_bit == 1 ? zero : not_zero, &other_color, Label::kNear);
    add(mask_scratch, mask_scratch);  // Shift left 1 by adding.
    j(zero, &word_boundary, Label::kNear);
    test(mask_scratch, Operand(bitmap_scratch, MemoryChunk::kHeaderSize));
    j(second_bit == 1 ? not_zero : zero, has_color, has_color_distance);
    jmp(&other_color, Label::kNear);
  
    bind(&word_boundary);
    test_b(Operand(bitmap_scratch, MemoryChunk::kHeaderSize + kPointerSize), 1);
  
    j(second_bit == 1 ? not_zero : zero, has_color, has_color_distance);
    bind(&other_color);
  }
  
  
  void MacroAssembler::GetMarkBits(Register addr_reg,
                                   Register bitmap_reg,
                                   Register mask_reg) {
    DCHECK(!AreAliased(addr_reg, mask_reg, bitmap_reg, ecx));
    mov(bitmap_reg, Immediate(~Page::kPageAlignmentMask));
    and_(bitmap_reg, addr_reg);
    mov(ecx, addr_reg);
    int shift =
        Bitmap::kBitsPerCellLog2 + kPointerSizeLog2 - Bitmap::kBytesPerCellLog2;
    shr(ecx, shift);
    and_(ecx,
         (Page::kPageAlignmentMask >> shift) & ~(Bitmap::kBytesPerCell - 1));
  
    add(bitmap_reg, ecx);
    mov(ecx, addr_reg);
    shr(ecx, kPointerSizeLog2);
    and_(ecx, (1 << Bitmap::kBitsPerCellLog2) - 1);
    mov(mask_reg, Immediate(1));
    shl_cl(mask_reg);
  }
  
  
  void MacroAssembler::EnsureNotWhite(
      Register value,
      Register bitmap_scratch,
      Register mask_scratch,
      Label* value_is_white_and_not_data,
      Label::Distance distance) {
    DCHECK(!AreAliased(value, bitmap_scratch, mask_scratch, ecx));
    GetMarkBits(value, bitmap_scratch, mask_scratch);
  
    // If the value is black or grey we don't need to do anything.
    DCHECK(strcmp(Marking::kWhiteBitPattern, "00") == 0);
    DCHECK(strcmp(Marking::kBlackBitPattern, "10") == 0);
    DCHECK(strcmp(Marking::kGreyBitPattern, "11") == 0);
    DCHECK(strcmp(Marking::kImpossibleBitPattern, "01") == 0);
  
    Label done;
  
    // Since both black and grey have a 1 in the first position and white does
    // not have a 1 there we only need to check one bit.
    test(mask_scratch, Operand(bitmap_scratch, MemoryChunk::kHeaderSize));
    j(not_zero, &done, Label::kNear);
  
    if (emit_debug_code()) {
      // Check for impossible bit pattern.
      Label ok;
      push(mask_scratch);
      // shl.  May overflow making the check conservative.
      add(mask_scratch, mask_scratch);
      test(mask_scratch, Operand(bitmap_scratch, MemoryChunk::kHeaderSize));
      j(zero, &ok, Label::kNear);
      int3();
      bind(&ok);
      pop(mask_scratch);
    }
  
    // Value is white.  We check whether it is data that doesn't need scanning.
    // Currently only checks for HeapNumber and non-cons strings.
    Register map = ecx;  // Holds map while checking type.
    Register length = ecx;  // Holds length of object after checking type.
    Label not_heap_number;
    Label is_data_object;
  
    // Check for heap-number
    mov(map, FieldOperand(value, HeapObject::kMapOffset));
    cmp(map, isolate()->factory()->heap_number_map());
    j(not_equal, &not_heap_number, Label::kNear);
    mov(length, Immediate(HeapNumber::kSize));
    jmp(&is_data_object, Label::kNear);
  
    bind(&not_heap_number);
    // Check for strings.
    DCHECK(kIsIndirectStringTag == 1 && kIsIndirectStringMask == 1);
    DCHECK(kNotStringTag == 0x80 && kIsNotStringMask == 0x80);
    // If it's a string and it's not a cons string then it's an object containing
    // no GC pointers.
    Register instance_type = ecx;
    movzx_b(instance_type, FieldOperand(map, Map::kInstanceTypeOffset));
    test_b(instance_type, kIsIndirectStringMask | kIsNotStringMask);
    j(not_zero, value_is_white_and_not_data);
    // It's a non-indirect (non-cons and non-slice) string.
    // If it's external, the length is just ExternalString::kSize.
    // Otherwise it's String::kHeaderSize + string->length() * (1 or 2).
    Label not_external;
    // External strings are the only ones with the kExternalStringTag bit
    // set.
    DCHECK_EQ(0, kSeqStringTag & kExternalStringTag);
    DCHECK_EQ(0, kConsStringTag & kExternalStringTag);
    test_b(instance_type, kExternalStringTag);
    j(zero, &not_external, Label::kNear);
    mov(length, Immediate(ExternalString::kSize));
    jmp(&is_data_object, Label::kNear);
  
    bind(&not_external);
    // Sequential string, either Latin1 or UC16.
    DCHECK(kOneByteStringTag == 0x04);
    and_(length, Immediate(kStringEncodingMask));
    xor_(length, Immediate(kStringEncodingMask));
    add(length, Immediate(0x04));
    // Value now either 4 (if Latin1) or 8 (if UC16), i.e., char-size shifted
    // by 2. If we multiply the string length as smi by this, it still
    // won't overflow a 32-bit value.
    DCHECK_EQ(SeqOneByteString::kMaxSize, SeqTwoByteString::kMaxSize);
    DCHECK(SeqOneByteString::kMaxSize <=
           static_cast<int>(0xffffffffu >> (2 + kSmiTagSize)));
    imul(length, FieldOperand(value, String::kLengthOffset));
    shr(length, 2 + kSmiTagSize + kSmiShiftSize);
    add(length, Immediate(SeqString::kHeaderSize + kObjectAlignmentMask));
    and_(length, Immediate(~kObjectAlignmentMask));
  
    bind(&is_data_object);
    // Value is a data object, and it is white.  Mark it black.  Since we know
    // that the object is white we can make it black by flipping one bit.
    or_(Operand(bitmap_scratch, MemoryChunk::kHeaderSize), mask_scratch);
  
    and_(bitmap_scratch, Immediate(~Page::kPageAlignmentMask));
    add(Operand(bitmap_scratch, MemoryChunk::kLiveBytesOffset),
        length);
    if (emit_debug_code()) {
      mov(length, Operand(bitmap_scratch, MemoryChunk::kLiveBytesOffset));
      cmp(length, Operand(bitmap_scratch, MemoryChunk::kSizeOffset));
      Check(less_equal, kLiveBytesCountOverflowChunkSize);
    }
  
    bind(&done);
  }
  
  
  void MacroAssembler::EnumLength(Register dst, Register map) {
    STATIC_ASSERT(Map::EnumLengthBits::kShift == 0);
    mov(dst, FieldOperand(map, Map::kBitField3Offset));
    and_(dst, Immediate(Map::EnumLengthBits::kMask));
    SmiTag(dst);
  }
  
  
  void MacroAssembler::CheckEnumCache(Label* call_runtime) {
    Label next, start;
    mov(ecx, eax);
  
    // Check if the enum length field is properly initialized, indicating that
    // there is an enum cache.
    mov(ebx, FieldOperand(ecx, HeapObject::kMapOffset));
  
    EnumLength(edx, ebx);
    cmp(edx, Immediate(Smi::FromInt(kInvalidEnumCacheSentinel)));
    j(equal, call_runtime);
  
    jmp(&start);
  
    bind(&next);
    mov(ebx, FieldOperand(ecx, HeapObject::kMapOffset));
  
    // For all objects but the receiver, check that the cache is empty.
    EnumLength(edx, ebx);
    cmp(edx, Immediate(Smi::FromInt(0)));
    j(not_equal, call_runtime);
  
    bind(&start);
  
    // Check that there are no elements. Register rcx contains the current JS
    // object we've reached through the prototype chain.
    Label no_elements;
    mov(ecx, FieldOperand(ecx, JSObject::kElementsOffset));
    cmp(ecx, isolate()->factory()->empty_fixed_array());
    j(equal, &no_elements);
  
    // Second chance, the object may be using the empty slow element dictionary.
    cmp(ecx, isolate()->factory()->empty_slow_element_dictionary());
    j(not_equal, call_runtime);
  
    bind(&no_elements);
    mov(ecx, FieldOperand(ebx, Map::kPrototypeOffset));
    cmp(ecx, isolate()->factory()->null_value());
    j(not_equal, &next);
  }
  
  
  void MacroAssembler::TestJSArrayForAllocationMemento(
      Register receiver_reg,
      Register scratch_reg,
      Label* no_memento_found) {
    ExternalReference new_space_start =
        ExternalReference::new_space_start(isolate());
    ExternalReference new_space_allocation_top =
        ExternalReference::new_space_allocation_top_address(isolate());
  
    lea(scratch_reg, Operand(receiver_reg,
        JSArray::kSize + AllocationMemento::kSize - kHeapObjectTag));
    cmp(scratch_reg, Immediate(new_space_start));
    j(less, no_memento_found);
    cmp(scratch_reg, Operand::StaticVariable(new_space_allocation_top));
    j(greater, no_memento_found);
    cmp(MemOperand(scratch_reg, -AllocationMemento::kSize),
        Immediate(isolate()->factory()->allocation_memento_map()));
  }
  
  
  void MacroAssembler::JumpIfDictionaryInPrototypeChain(
      Register object,
      Register scratch0,
      Register scratch1,
      Label* found) {
    DCHECK(!scratch1.is(scratch0));
    Factory* factory = isolate()->factory();
    Register current = scratch0;
    Label loop_again, end;
  
    // scratch contained elements pointer.
    mov(current, object);
    mov(current, FieldOperand(current, HeapObject::kMapOffset));
    mov(current, FieldOperand(current, Map::kPrototypeOffset));
    cmp(current, Immediate(factory->null_value()));
    j(equal, &end);
  
    // Loop based on the map going up the prototype chain.
    bind(&loop_again);
    mov(current, FieldOperand(current, HeapObject::kMapOffset));
    STATIC_ASSERT(JS_PROXY_TYPE < JS_OBJECT_TYPE);
    STATIC_ASSERT(JS_VALUE_TYPE < JS_OBJECT_TYPE);
    CmpInstanceType(current, JS_OBJECT_TYPE);
    j(below, found);
    mov(scratch1, FieldOperand(current, Map::kBitField2Offset));
    DecodeField<Map::ElementsKindBits>(scratch1);
    cmp(scratch1, Immediate(DICTIONARY_ELEMENTS));
    j(equal, found);
    mov(current, FieldOperand(current, Map::kPrototypeOffset));
    cmp(current, Immediate(factory->null_value()));
    j(not_equal, &loop_again);
  
    bind(&end);
  }
  
  
  void MacroAssembler::TruncatingDiv(Register dividend, int32_t divisor) {
    DCHECK(!dividend.is(eax));
    DCHECK(!dividend.is(edx));
    base::MagicNumbersForDivision<uint32_t> mag =
        base::SignedDivisionByConstant(static_cast<uint32_t>(divisor));
    mov(eax, Immediate(mag.multiplier));
    imul(dividend);
    bool neg = (mag.multiplier & (static_cast<uint32_t>(1) << 31)) != 0;
    if (divisor > 0 && neg) add(edx, dividend);
    if (divisor < 0 && !neg && mag.multiplier > 0) sub(edx, dividend);
    if (mag.shift > 0) sar(edx, mag.shift);
    mov(eax, dividend);
    shr(eax, 31);
    add(edx, eax);
  }
  
  
  }  // namespace internal
  }  // namespace v8
  
  #endif  // V8_TARGET_ARCH_X87
  