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.
  
  #ifndef V8_X87_MACRO_ASSEMBLER_X87_H_
  #define V8_X87_MACRO_ASSEMBLER_X87_H_
  
  #include "src/assembler.h"
  #include "src/bailout-reason.h"
  #include "src/frames.h"
  #include "src/globals.h"
  
  namespace v8 {
  namespace internal {
  
  // Convenience for platform-independent signatures.  We do not normally
  // distinguish memory operands from other operands on ia32.
  typedef Operand MemOperand;
  
  enum RememberedSetAction { EMIT_REMEMBERED_SET, OMIT_REMEMBERED_SET };
  enum SmiCheck { INLINE_SMI_CHECK, OMIT_SMI_CHECK };
  enum PointersToHereCheck {
    kPointersToHereMaybeInteresting,
    kPointersToHereAreAlwaysInteresting
  };
  
  
  enum RegisterValueType {
    REGISTER_VALUE_IS_SMI,
    REGISTER_VALUE_IS_INT32
  };
  
  
  #ifdef DEBUG
  bool AreAliased(Register reg1,
                  Register reg2,
                  Register reg3 = no_reg,
                  Register reg4 = no_reg,
                  Register reg5 = no_reg,
                  Register reg6 = no_reg,
                  Register reg7 = no_reg,
                  Register reg8 = no_reg);
  #endif
  
  
  // MacroAssembler implements a collection of frequently used macros.
  class MacroAssembler: public Assembler {
   public:
    // The isolate parameter can be NULL if the macro assembler should
    // not use isolate-dependent functionality. In this case, it's the
    // responsibility of the caller to never invoke such function on the
    // macro assembler.
    MacroAssembler(Isolate* isolate, void* buffer, int size);
  
    void Load(Register dst, const Operand& src, Representation r);
    void Store(Register src, const Operand& dst, Representation r);
  
    // Operations on roots in the root-array.
    void LoadRoot(Register destination, Heap::RootListIndex index);
    void StoreRoot(Register source, Register scratch, Heap::RootListIndex index);
    void CompareRoot(Register with, Register scratch, Heap::RootListIndex index);
    // These methods can only be used with constant roots (i.e. non-writable
    // and not in new space).
    void CompareRoot(Register with, Heap::RootListIndex index);
    void CompareRoot(const Operand& with, Heap::RootListIndex index);
  
    // ---------------------------------------------------------------------------
    // GC Support
    enum RememberedSetFinalAction {
      kReturnAtEnd,
      kFallThroughAtEnd
    };
  
    // Record in the remembered set the fact that we have a pointer to new space
    // at the address pointed to by the addr register.  Only works if addr is not
    // in new space.
    void RememberedSetHelper(Register object,  // Used for debug code.
                             Register addr, Register scratch,
                             SaveFPRegsMode save_fp,
                             RememberedSetFinalAction and_then);
  
    void CheckPageFlag(Register object,
                       Register scratch,
                       int mask,
                       Condition cc,
                       Label* condition_met,
                       Label::Distance condition_met_distance = Label::kFar);
  
    void CheckPageFlagForMap(
        Handle<Map> map,
        int mask,
        Condition cc,
        Label* condition_met,
        Label::Distance condition_met_distance = Label::kFar);
  
    // Check if object is in new space.  Jumps if the object is not in new space.
    // The register scratch can be object itself, but scratch will be clobbered.
    void JumpIfNotInNewSpace(Register object,
                             Register scratch,
                             Label* branch,
                             Label::Distance distance = Label::kFar) {
      InNewSpace(object, scratch, zero, branch, distance);
    }
  
    // Check if object is in new space.  Jumps if the object is in new space.
    // The register scratch can be object itself, but it will be clobbered.
    void JumpIfInNewSpace(Register object,
                          Register scratch,
                          Label* branch,
                          Label::Distance distance = Label::kFar) {
      InNewSpace(object, scratch, not_zero, branch, distance);
    }
  
    // Check if an object has a given incremental marking color.  Also uses ecx!
    void HasColor(Register object,
                  Register scratch0,
                  Register scratch1,
                  Label* has_color,
                  Label::Distance has_color_distance,
                  int first_bit,
                  int second_bit);
  
    void JumpIfBlack(Register object,
                     Register scratch0,
                     Register scratch1,
                     Label* on_black,
                     Label::Distance on_black_distance = Label::kFar);
  
    // Checks the color of an object.  If the object is already grey or black
    // then we just fall through, since it is already live.  If it is white and
    // we can determine that it doesn't need to be scanned, then we just mark it
    // black and fall through.  For the rest we jump to the label so the
    // incremental marker can fix its assumptions.
    void EnsureNotWhite(Register object,
                        Register scratch1,
                        Register scratch2,
                        Label* object_is_white_and_not_data,
                        Label::Distance distance);
  
    // Notify the garbage collector that we wrote a pointer into an object.
    // |object| is the object being stored into, |value| is the object being
    // stored.  value and scratch registers are clobbered by the operation.
    // The offset is the offset from the start of the object, not the offset from
    // the tagged HeapObject pointer.  For use with FieldOperand(reg, off).
    void RecordWriteField(
        Register object, int offset, Register value, Register scratch,
        SaveFPRegsMode save_fp,
        RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,
        SmiCheck smi_check = INLINE_SMI_CHECK,
        PointersToHereCheck pointers_to_here_check_for_value =
            kPointersToHereMaybeInteresting);
  
    // As above, but the offset has the tag presubtracted.  For use with
    // Operand(reg, off).
    void RecordWriteContextSlot(
        Register context, int offset, Register value, Register scratch,
        SaveFPRegsMode save_fp,
        RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,
        SmiCheck smi_check = INLINE_SMI_CHECK,
        PointersToHereCheck pointers_to_here_check_for_value =
            kPointersToHereMaybeInteresting) {
      RecordWriteField(context, offset + kHeapObjectTag, value, scratch, save_fp,
                       remembered_set_action, smi_check,
                       pointers_to_here_check_for_value);
    }
  
    // Notify the garbage collector that we wrote a pointer into a fixed array.
    // |array| is the array being stored into, |value| is the
    // object being stored.  |index| is the array index represented as a
    // Smi. All registers are clobbered by the operation RecordWriteArray
    // filters out smis so it does not update the write barrier if the
    // value is a smi.
    void RecordWriteArray(
        Register array, Register value, Register index, SaveFPRegsMode save_fp,
        RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,
        SmiCheck smi_check = INLINE_SMI_CHECK,
        PointersToHereCheck pointers_to_here_check_for_value =
            kPointersToHereMaybeInteresting);
  
    // For page containing |object| mark region covering |address|
    // dirty. |object| is the object being stored into, |value| is the
    // object being stored. The address and value registers are clobbered by the
    // operation. RecordWrite filters out smis so it does not update the
    // write barrier if the value is a smi.
    void RecordWrite(
        Register object, Register address, Register value, SaveFPRegsMode save_fp,
        RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,
        SmiCheck smi_check = INLINE_SMI_CHECK,
        PointersToHereCheck pointers_to_here_check_for_value =
            kPointersToHereMaybeInteresting);
  
    // For page containing |object| mark the region covering the object's map
    // dirty. |object| is the object being stored into, |map| is the Map object
    // that was stored.
    void RecordWriteForMap(Register object, Handle<Map> map, Register scratch1,
                           Register scratch2, SaveFPRegsMode save_fp);
  
    // ---------------------------------------------------------------------------
    // Debugger Support
  
    void DebugBreak();
  
    // Generates function and stub prologue code.
    void StubPrologue();
    void Prologue(bool code_pre_aging);
  
    // Enter specific kind of exit frame. Expects the number of
    // arguments in register eax and sets up the number of arguments in
    // register edi and the pointer to the first argument in register
    // esi.
    void EnterExitFrame(bool save_doubles);
  
    void EnterApiExitFrame(int argc);
  
    // Leave the current exit frame. Expects the return value in
    // register eax:edx (untouched) and the pointer to the first
    // argument in register esi.
    void LeaveExitFrame(bool save_doubles);
  
    // Leave the current exit frame. Expects the return value in
    // register eax (untouched).
    void LeaveApiExitFrame(bool restore_context);
  
    // Find the function context up the context chain.
    void LoadContext(Register dst, int context_chain_length);
  
    // Conditionally load the cached Array transitioned map of type
    // transitioned_kind from the native context if the map in register
    // map_in_out is the cached Array map in the native context of
    // expected_kind.
    void LoadTransitionedArrayMapConditional(
        ElementsKind expected_kind,
        ElementsKind transitioned_kind,
        Register map_in_out,
        Register scratch,
        Label* no_map_match);
  
    // Load the global function with the given index.
    void LoadGlobalFunction(int index, Register function);
  
    // Load the initial map from the global function. The registers
    // function and map can be the same.
    void LoadGlobalFunctionInitialMap(Register function, Register map);
  
    // Push and pop the registers that can hold pointers.
    void PushSafepointRegisters() { pushad(); }
    void PopSafepointRegisters() { popad(); }
    // Store the value in register/immediate src in the safepoint
    // register stack slot for register dst.
    void StoreToSafepointRegisterSlot(Register dst, Register src);
    void StoreToSafepointRegisterSlot(Register dst, Immediate src);
    void LoadFromSafepointRegisterSlot(Register dst, Register src);
  
    void LoadHeapObject(Register result, Handle<HeapObject> object);
    void CmpHeapObject(Register reg, Handle<HeapObject> object);
    void PushHeapObject(Handle<HeapObject> object);
  
    void LoadObject(Register result, Handle<Object> object) {
      AllowDeferredHandleDereference heap_object_check;
      if (object->IsHeapObject()) {
        LoadHeapObject(result, Handle<HeapObject>::cast(object));
      } else {
        Move(result, Immediate(object));
      }
    }
  
    void CmpObject(Register reg, Handle<Object> object) {
      AllowDeferredHandleDereference heap_object_check;
      if (object->IsHeapObject()) {
        CmpHeapObject(reg, Handle<HeapObject>::cast(object));
      } else {
        cmp(reg, Immediate(object));
      }
    }
  
    void CmpWeakValue(Register value, Handle<WeakCell> cell, Register scratch);
    void GetWeakValue(Register value, Handle<WeakCell> cell);
    void LoadWeakValue(Register value, Handle<WeakCell> cell, Label* miss);
  
    // ---------------------------------------------------------------------------
    // JavaScript invokes
  
    // Invoke the JavaScript function code by either calling or jumping.
    void InvokeCode(Register code,
                    const ParameterCount& expected,
                    const ParameterCount& actual,
                    InvokeFlag flag,
                    const CallWrapper& call_wrapper) {
      InvokeCode(Operand(code), expected, actual, flag, call_wrapper);
    }
  
    void InvokeCode(const Operand& code,
                    const ParameterCount& expected,
                    const ParameterCount& actual,
                    InvokeFlag flag,
                    const CallWrapper& call_wrapper);
  
    // Invoke the JavaScript function in the given register. Changes the
    // current context to the context in the function before invoking.
    void InvokeFunction(Register function,
                        const ParameterCount& actual,
                        InvokeFlag flag,
                        const CallWrapper& call_wrapper);
  
    void InvokeFunction(Register function,
                        const ParameterCount& expected,
                        const ParameterCount& actual,
                        InvokeFlag flag,
                        const CallWrapper& call_wrapper);
  
    void InvokeFunction(Handle<JSFunction> function,
                        const ParameterCount& expected,
                        const ParameterCount& actual,
                        InvokeFlag flag,
                        const CallWrapper& call_wrapper);
  
    // Invoke specified builtin JavaScript function. Adds an entry to
    // the unresolved list if the name does not resolve.
    void InvokeBuiltin(Builtins::JavaScript id,
                       InvokeFlag flag,
                       const CallWrapper& call_wrapper = NullCallWrapper());
  
    // Store the function for the given builtin in the target register.
    void GetBuiltinFunction(Register target, Builtins::JavaScript id);
  
    // Store the code object for the given builtin in the target register.
    void GetBuiltinEntry(Register target, Builtins::JavaScript id);
  
    // Expression support
    // Support for constant splitting.
    bool IsUnsafeImmediate(const Immediate& x);
    void SafeMove(Register dst, const Immediate& x);
    void SafePush(const Immediate& x);
  
    // Compare object type for heap object.
    // Incoming register is heap_object and outgoing register is map.
    void CmpObjectType(Register heap_object, InstanceType type, Register map);
  
    // Compare instance type for map.
    void CmpInstanceType(Register map, InstanceType type);
  
    // Check if a map for a JSObject indicates that the object has fast elements.
    // Jump to the specified label if it does not.
    void CheckFastElements(Register map,
                           Label* fail,
                           Label::Distance distance = Label::kFar);
  
    // Check if a map for a JSObject indicates that the object can have both smi
    // and HeapObject elements.  Jump to the specified label if it does not.
    void CheckFastObjectElements(Register map,
                                 Label* fail,
                                 Label::Distance distance = Label::kFar);
  
    // Check if a map for a JSObject indicates that the object has fast smi only
    // elements.  Jump to the specified label if it does not.
    void CheckFastSmiElements(Register map,
                              Label* fail,
                              Label::Distance distance = Label::kFar);
  
    // Check to see if maybe_number can be stored as a double in
    // FastDoubleElements. If it can, store it at the index specified by key in
    // the FastDoubleElements array elements, otherwise jump to fail.
    void StoreNumberToDoubleElements(Register maybe_number,
                                     Register elements,
                                     Register key,
                                     Register scratch,
                                     Label* fail,
                                     int offset = 0);
  
    // Compare an object's map with the specified map.
    void CompareMap(Register obj, Handle<Map> map);
  
    // Check if the map of an object is equal to a specified map and branch to
    // label if not. Skip the smi check if not required (object is known to be a
    // heap object). If mode is ALLOW_ELEMENT_TRANSITION_MAPS, then also match
    // against maps that are ElementsKind transition maps of the specified map.
    void CheckMap(Register obj,
                  Handle<Map> map,
                  Label* fail,
                  SmiCheckType smi_check_type);
  
    // Check if the map of an object is equal to a specified weak map and branch
    // to a specified target if equal. Skip the smi check if not required
    // (object is known to be a heap object)
    void DispatchWeakMap(Register obj, Register scratch1, Register scratch2,
                         Handle<WeakCell> cell, Handle<Code> success,
                         SmiCheckType smi_check_type);
  
    // Check if the object in register heap_object is a string. Afterwards the
    // register map contains the object map and the register instance_type
    // contains the instance_type. The registers map and instance_type can be the
    // same in which case it contains the instance type afterwards. Either of the
    // registers map and instance_type can be the same as heap_object.
    Condition IsObjectStringType(Register heap_object,
                                 Register map,
                                 Register instance_type);
  
    // Check if the object in register heap_object is a name. Afterwards the
    // register map contains the object map and the register instance_type
    // contains the instance_type. The registers map and instance_type can be the
    // same in which case it contains the instance type afterwards. Either of the
    // registers map and instance_type can be the same as heap_object.
    Condition IsObjectNameType(Register heap_object,
                               Register map,
                               Register instance_type);
  
    // Check if a heap object's type is in the JSObject range, not including
    // JSFunction.  The object's map will be loaded in the map register.
    // Any or all of the three registers may be the same.
    // The contents of the scratch register will always be overwritten.
    void IsObjectJSObjectType(Register heap_object,
                              Register map,
                              Register scratch,
                              Label* fail);
  
    // The contents of the scratch register will be overwritten.
    void IsInstanceJSObjectType(Register map, Register scratch, Label* fail);
  
    // FCmp is similar to integer cmp, but requires unsigned
    // jcc instructions (je, ja, jae, jb, jbe, je, and jz).
    void FCmp();
    void FXamMinusZero();
    void FXamSign();
    void X87CheckIA();
    void X87SetRC(int rc);
    void X87SetFPUCW(int cw);
  
    void ClampUint8(Register reg);
    void ClampTOSToUint8(Register result_reg);
  
    void SlowTruncateToI(Register result_reg, Register input_reg,
        int offset = HeapNumber::kValueOffset - kHeapObjectTag);
  
    void TruncateHeapNumberToI(Register result_reg, Register input_reg);
    void TruncateX87TOSToI(Register result_reg);
  
    void X87TOSToI(Register result_reg, MinusZeroMode minus_zero_mode,
        Label* lost_precision, Label* is_nan, Label* minus_zero,
        Label::Distance dst = Label::kFar);
  
    // Smi tagging support.
    void SmiTag(Register reg) {
      STATIC_ASSERT(kSmiTag == 0);
      STATIC_ASSERT(kSmiTagSize == 1);
      add(reg, reg);
    }
    void SmiUntag(Register reg) {
      sar(reg, kSmiTagSize);
    }
  
    // Modifies the register even if it does not contain a Smi!
    void SmiUntag(Register reg, Label* is_smi) {
      STATIC_ASSERT(kSmiTagSize == 1);
      sar(reg, kSmiTagSize);
      STATIC_ASSERT(kSmiTag == 0);
      j(not_carry, is_smi);
    }
  
    void LoadUint32NoSSE2(Register src) {
      LoadUint32NoSSE2(Operand(src));
    }
    void LoadUint32NoSSE2(const Operand& src);
  
    // Jump the register contains a smi.
    inline void JumpIfSmi(Register value,
                          Label* smi_label,
                          Label::Distance distance = Label::kFar) {
      test(value, Immediate(kSmiTagMask));
      j(zero, smi_label, distance);
    }
    // Jump if the operand is a smi.
    inline void JumpIfSmi(Operand value,
                          Label* smi_label,
                          Label::Distance distance = Label::kFar) {
      test(value, Immediate(kSmiTagMask));
      j(zero, smi_label, distance);
    }
    // Jump if register contain a non-smi.
    inline void JumpIfNotSmi(Register value,
                             Label* not_smi_label,
                             Label::Distance distance = Label::kFar) {
      test(value, Immediate(kSmiTagMask));
      j(not_zero, not_smi_label, distance);
    }
  
    void LoadInstanceDescriptors(Register map, Register descriptors);
    void EnumLength(Register dst, Register map);
    void NumberOfOwnDescriptors(Register dst, Register map);
    void LoadAccessor(Register dst, Register holder, int accessor_index,
                      AccessorComponent accessor);
  
    template<typename Field>
    void DecodeField(Register reg) {
      static const int shift = Field::kShift;
      static const int mask = Field::kMask >> Field::kShift;
      if (shift != 0) {
        sar(reg, shift);
      }
      and_(reg, Immediate(mask));
    }
  
    template<typename Field>
    void DecodeFieldToSmi(Register reg) {
      static const int shift = Field::kShift;
      static const int mask = (Field::kMask >> Field::kShift) << kSmiTagSize;
      STATIC_ASSERT((mask & (0x80000000u >> (kSmiTagSize - 1))) == 0);
      STATIC_ASSERT(kSmiTag == 0);
      if (shift < kSmiTagSize) {
        shl(reg, kSmiTagSize - shift);
      } else if (shift > kSmiTagSize) {
        sar(reg, shift - kSmiTagSize);
      }
      and_(reg, Immediate(mask));
    }
  
    // Abort execution if argument is not a number, enabled via --debug-code.
    void AssertNumber(Register object);
  
    // Abort execution if argument is not a smi, enabled via --debug-code.
    void AssertSmi(Register object);
  
    // Abort execution if argument is a smi, enabled via --debug-code.
    void AssertNotSmi(Register object);
  
    // Abort execution if argument is not a string, enabled via --debug-code.
    void AssertString(Register object);
  
    // Abort execution if argument is not a name, enabled via --debug-code.
    void AssertName(Register object);
  
    // Abort execution if argument is not undefined or an AllocationSite, enabled
    // via --debug-code.
    void AssertUndefinedOrAllocationSite(Register object);
  
    // ---------------------------------------------------------------------------
    // Exception handling
  
    // Push a new try handler and link it into try handler chain.
    void PushTryHandler(StackHandler::Kind kind, int handler_index);
  
    // Unlink the stack handler on top of the stack from the try handler chain.
    void PopTryHandler();
  
    // ---------------------------------------------------------------------------
    // Inline caching support
  
    // Generate code for checking access rights - used for security checks
    // on access to global objects across environments. The holder register
    // is left untouched, but the scratch register is clobbered.
    void CheckAccessGlobalProxy(Register holder_reg,
                                Register scratch1,
                                Register scratch2,
                                Label* miss);
  
    void GetNumberHash(Register r0, Register scratch);
  
    void LoadFromNumberDictionary(Label* miss,
                                  Register elements,
                                  Register key,
                                  Register r0,
                                  Register r1,
                                  Register r2,
                                  Register result);
  
  
    // ---------------------------------------------------------------------------
    // Allocation support
  
    // Allocate an object in new space or old pointer space. If the given space
    // is exhausted control continues at the gc_required label. The allocated
    // object is returned in result and end of the new object is returned in
    // result_end. The register scratch can be passed as no_reg in which case
    // an additional object reference will be added to the reloc info. The
    // returned pointers in result and result_end have not yet been tagged as
    // heap objects. If result_contains_top_on_entry is true the content of
    // result is known to be the allocation top on entry (could be result_end
    // from a previous call). If result_contains_top_on_entry is true scratch
    // should be no_reg as it is never used.
    void Allocate(int object_size,
                  Register result,
                  Register result_end,
                  Register scratch,
                  Label* gc_required,
                  AllocationFlags flags);
  
    void 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);
  
    void Allocate(Register object_size,
                  Register result,
                  Register result_end,
                  Register scratch,
                  Label* gc_required,
                  AllocationFlags flags);
  
    // Undo allocation in new space. The object passed and objects allocated after
    // it will no longer be allocated. Make sure that no pointers are left to the
    // object(s) no longer allocated as they would be invalid when allocation is
    // un-done.
    void UndoAllocationInNewSpace(Register object);
  
    // Allocate a heap number in new space with undefined value. The
    // register scratch2 can be passed as no_reg; the others must be
    // valid registers. Returns tagged pointer in result register, or
    // jumps to gc_required if new space is full.
    void AllocateHeapNumber(Register result,
                            Register scratch1,
                            Register scratch2,
                            Label* gc_required,
                            MutableMode mode = IMMUTABLE);
  
    // Allocate a sequential string. All the header fields of the string object
    // are initialized.
    void AllocateTwoByteString(Register result,
                               Register length,
                               Register scratch1,
                               Register scratch2,
                               Register scratch3,
                               Label* gc_required);
    void AllocateOneByteString(Register result, Register length,
                               Register scratch1, Register scratch2,
                               Register scratch3, Label* gc_required);
    void AllocateOneByteString(Register result, int length, Register scratch1,
                               Register scratch2, Label* gc_required);
  
    // Allocate a raw cons string object. Only the map field of the result is
    // initialized.
    void AllocateTwoByteConsString(Register result,
                            Register scratch1,
                            Register scratch2,
                            Label* gc_required);
    void AllocateOneByteConsString(Register result, Register scratch1,
                                   Register scratch2, Label* gc_required);
  
    // Allocate a raw sliced string object. Only the map field of the result is
    // initialized.
    void AllocateTwoByteSlicedString(Register result,
                              Register scratch1,
                              Register scratch2,
                              Label* gc_required);
    void AllocateOneByteSlicedString(Register result, Register scratch1,
                                     Register scratch2, Label* gc_required);
  
    // Copy memory, byte-by-byte, from source to destination.  Not optimized for
    // long or aligned copies.
    // The contents of index and scratch are destroyed.
    void CopyBytes(Register source,
                   Register destination,
                   Register length,
                   Register scratch);
  
    // Initialize fields with filler values.  Fields starting at |start_offset|
    // not including end_offset are overwritten with the value in |filler|.  At
    // the end the loop, |start_offset| takes the value of |end_offset|.
    void InitializeFieldsWithFiller(Register start_offset,
                                    Register end_offset,
                                    Register filler);
  
    // ---------------------------------------------------------------------------
    // Support functions.
  
    // Check a boolean-bit of a Smi field.
    void BooleanBitTest(Register object, int field_offset, int bit_index);
  
    // Check if result is zero and op is negative.
    void NegativeZeroTest(Register result, Register op, Label* then_label);
  
    // Check if result is zero and any of op1 and op2 are negative.
    // Register scratch is destroyed, and it must be different from op2.
    void NegativeZeroTest(Register result, Register op1, Register op2,
                          Register scratch, Label* then_label);
  
    // Machine code version of Map::GetConstructor().
    // |temp| holds |result|'s map when done.
    void GetMapConstructor(Register result, Register map, Register temp);
  
    // Try to get function prototype of a function and puts the value in
    // the result register. Checks that the function really is a
    // function and jumps to the miss label if the fast checks fail. The
    // function register will be untouched; the other registers may be
    // clobbered.
    void TryGetFunctionPrototype(Register function,
                                 Register result,
                                 Register scratch,
                                 Label* miss,
                                 bool miss_on_bound_function = false);
  
    // Picks out an array index from the hash field.
    // Register use:
    //   hash - holds the index's hash. Clobbered.
    //   index - holds the overwritten index on exit.
    void IndexFromHash(Register hash, Register index);
  
    // ---------------------------------------------------------------------------
    // Runtime calls
  
    // Call a code stub.  Generate the code if necessary.
    void CallStub(CodeStub* stub, TypeFeedbackId ast_id = TypeFeedbackId::None());
  
    // Tail call a code stub (jump).  Generate the code if necessary.
    void TailCallStub(CodeStub* stub);
  
    // Return from a code stub after popping its arguments.
    void StubReturn(int argc);
  
    // Call a runtime routine.
    void CallRuntime(const Runtime::Function* f, int num_arguments,
                     SaveFPRegsMode save_doubles = kDontSaveFPRegs);
    void CallRuntimeSaveDoubles(Runtime::FunctionId id) {
      const Runtime::Function* function = Runtime::FunctionForId(id);
      CallRuntime(function, function->nargs, kSaveFPRegs);
    }
  
    // Convenience function: Same as above, but takes the fid instead.
    void CallRuntime(Runtime::FunctionId id, int num_arguments,
                     SaveFPRegsMode save_doubles = kDontSaveFPRegs) {
      CallRuntime(Runtime::FunctionForId(id), num_arguments, save_doubles);
    }
  
    // Convenience function: call an external reference.
    void CallExternalReference(ExternalReference ref, int num_arguments);
  
    // Tail call of a runtime routine (jump).
    // Like JumpToExternalReference, but also takes care of passing the number
    // of parameters.
    void TailCallExternalReference(const ExternalReference& ext,
                                   int num_arguments,
                                   int result_size);
  
    // Convenience function: tail call a runtime routine (jump).
    void TailCallRuntime(Runtime::FunctionId fid,
                         int num_arguments,
                         int result_size);
  
    // Before calling a C-function from generated code, align arguments on stack.
    // After aligning the frame, arguments must be stored in esp[0], esp[4],
    // etc., not pushed. The argument count assumes all arguments are word sized.
    // Some compilers/platforms require the stack to be aligned when calling
    // C++ code.
    // Needs a scratch register to do some arithmetic. This register will be
    // trashed.
    void PrepareCallCFunction(int num_arguments, Register scratch);
  
    // Calls a C function and cleans up the space for arguments allocated
    // by PrepareCallCFunction. The called function is not allowed to trigger a
    // garbage collection, since that might move the code and invalidate the
    // return address (unless this is somehow accounted for by the called
    // function).
    void CallCFunction(ExternalReference function, int num_arguments);
    void CallCFunction(Register function, int num_arguments);
  
    // Jump to a runtime routine.
    void JumpToExternalReference(const ExternalReference& ext);
  
    // ---------------------------------------------------------------------------
    // Utilities
  
    void Ret();
  
    // Return and drop arguments from stack, where the number of arguments
    // may be bigger than 2^16 - 1.  Requires a scratch register.
    void Ret(int bytes_dropped, Register scratch);
  
    // Emit code to discard a non-negative number of pointer-sized elements
    // from the stack, clobbering only the esp register.
    void Drop(int element_count);
  
    void Call(Label* target) { call(target); }
    void Push(Register src) { push(src); }
    void Pop(Register dst) { pop(dst); }
  
    // Emit call to the code we are currently generating.
    void CallSelf() {
      Handle<Code> self(reinterpret_cast<Code**>(CodeObject().location()));
      call(self, RelocInfo::CODE_TARGET);
    }
  
    // Move if the registers are not identical.
    void Move(Register target, Register source);
  
    // Move a constant into a destination using the most efficient encoding.
    void Move(Register dst, const Immediate& x);
    void Move(const Operand& dst, const Immediate& x);
  
    // Push a handle value.
    void Push(Handle<Object> handle) { push(Immediate(handle)); }
    void Push(Smi* smi) { Push(Handle<Smi>(smi, isolate())); }
  
    Handle<Object> CodeObject() {
      DCHECK(!code_object_.is_null());
      return code_object_;
    }
  
    // Insert code to verify that the x87 stack has the specified depth (0-7)
    void VerifyX87StackDepth(uint32_t depth);
  
    // Emit code for a truncating division by a constant. The dividend register is
    // unchanged, the result is in edx, and eax gets clobbered.
    void TruncatingDiv(Register dividend, int32_t divisor);
  
    // ---------------------------------------------------------------------------
    // StatsCounter support
  
    void SetCounter(StatsCounter* counter, int value);
    void IncrementCounter(StatsCounter* counter, int value);
    void DecrementCounter(StatsCounter* counter, int value);
    void IncrementCounter(Condition cc, StatsCounter* counter, int value);
    void DecrementCounter(Condition cc, StatsCounter* counter, int value);
  
  
    // ---------------------------------------------------------------------------
    // Debugging
  
    // Calls Abort(msg) if the condition cc is not satisfied.
    // Use --debug_code to enable.
    void Assert(Condition cc, BailoutReason reason);
  
    void AssertFastElements(Register elements);
  
    // Like Assert(), but always enabled.
    void Check(Condition cc, BailoutReason reason);
  
    // Print a message to stdout and abort execution.
    void Abort(BailoutReason reason);
  
    // Check that the stack is aligned.
    void CheckStackAlignment();
  
    // Verify restrictions about code generated in stubs.
    void set_generating_stub(bool value) { generating_stub_ = value; }
    bool generating_stub() { return generating_stub_; }
    void set_has_frame(bool value) { has_frame_ = value; }
    bool has_frame() { return has_frame_; }
    inline bool AllowThisStubCall(CodeStub* stub);
  
    // ---------------------------------------------------------------------------
    // String utilities.
  
    // Generate code to do a lookup in the number string cache. If the number in
    // the register object is found in the cache the generated code falls through
    // with the result in the result register. The object and the result register
    // can be the same. If the number is not found in the cache the code jumps to
    // the label not_found with only the content of register object unchanged.
    void LookupNumberStringCache(Register object,
                                 Register result,
                                 Register scratch1,
                                 Register scratch2,
                                 Label* not_found);
  
    // Check whether the instance type represents a flat one-byte string. Jump to
    // the label if not. If the instance type can be scratched specify same
    // register for both instance type and scratch.
    void JumpIfInstanceTypeIsNotSequentialOneByte(
        Register instance_type, Register scratch,
        Label* on_not_flat_one_byte_string);
  
    // Checks if both objects are sequential one-byte strings, and jumps to label
    // if either is not.
    void JumpIfNotBothSequentialOneByteStrings(
        Register object1, Register object2, Register scratch1, Register scratch2,
        Label* on_not_flat_one_byte_strings);
  
    // Checks if the given register or operand is a unique name
    void JumpIfNotUniqueNameInstanceType(Register reg, Label* not_unique_name,
                                         Label::Distance distance = Label::kFar) {
      JumpIfNotUniqueNameInstanceType(Operand(reg), not_unique_name, distance);
    }
  
    void JumpIfNotUniqueNameInstanceType(Operand operand, Label* not_unique_name,
                                         Label::Distance distance = Label::kFar);
  
    void EmitSeqStringSetCharCheck(Register string,
                                   Register index,
                                   Register value,
                                   uint32_t encoding_mask);
  
    static int SafepointRegisterStackIndex(Register reg) {
      return SafepointRegisterStackIndex(reg.code());
    }
  
    // Activation support.
    void EnterFrame(StackFrame::Type type);
    void EnterFrame(StackFrame::Type type, bool load_constant_pool_pointer_reg);
    void LeaveFrame(StackFrame::Type type);
  
    // Expects object in eax and returns map with validated enum cache
    // in eax.  Assumes that any other register can be used as a scratch.
    void CheckEnumCache(Label* call_runtime);
  
    // AllocationMemento support. Arrays may have an associated
    // AllocationMemento object that can be checked for in order to pretransition
    // to another type.
    // On entry, receiver_reg should point to the array object.
    // scratch_reg gets clobbered.
    // If allocation info is present, conditional code is set to equal.
    void TestJSArrayForAllocationMemento(Register receiver_reg,
                                         Register scratch_reg,
                                         Label* no_memento_found);
  
    void JumpIfJSArrayHasAllocationMemento(Register receiver_reg,
                                           Register scratch_reg,
                                           Label* memento_found) {
      Label no_memento_found;
      TestJSArrayForAllocationMemento(receiver_reg, scratch_reg,
                                      &no_memento_found);
      j(equal, memento_found);
      bind(&no_memento_found);
    }
  
    // Jumps to found label if a prototype map has dictionary elements.
    void JumpIfDictionaryInPrototypeChain(Register object, Register scratch0,
                                          Register scratch1, Label* found);
  
   private:
    bool generating_stub_;
    bool has_frame_;
    // This handle will be patched with the code object on installation.
    Handle<Object> code_object_;
  
    // Helper functions for generating invokes.
    void 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_distance,
                        const CallWrapper& call_wrapper = NullCallWrapper());
  
    void EnterExitFramePrologue();
    void EnterExitFrameEpilogue(int argc, bool save_doubles);
  
    void LeaveExitFrameEpilogue(bool restore_context);
  
    // Allocation support helpers.
    void LoadAllocationTopHelper(Register result,
                                 Register scratch,
                                 AllocationFlags flags);
  
    void UpdateAllocationTopHelper(Register result_end,
                                   Register scratch,
                                   AllocationFlags flags);
  
    // Helper for implementing JumpIfNotInNewSpace and JumpIfInNewSpace.
    void InNewSpace(Register object,
                    Register scratch,
                    Condition cc,
                    Label* condition_met,
                    Label::Distance condition_met_distance = Label::kFar);
  
    // Helper for finding the mark bits for an address.  Afterwards, the
    // bitmap register points at the word with the mark bits and the mask
    // the position of the first bit.  Uses ecx as scratch and leaves addr_reg
    // unchanged.
    inline void GetMarkBits(Register addr_reg,
                            Register bitmap_reg,
                            Register mask_reg);
  
    // Compute memory operands for safepoint stack slots.
    Operand SafepointRegisterSlot(Register reg);
    static int SafepointRegisterStackIndex(int reg_code);
  
    // Needs access to SafepointRegisterStackIndex for compiled frame
    // traversal.
    friend class StandardFrame;
  };
  
  
  // The code patcher is used to patch (typically) small parts of code e.g. for
  // debugging and other types of instrumentation. When using the code patcher
  // the exact number of bytes specified must be emitted. Is not legal to emit
  // relocation information. If any of these constraints are violated it causes
  // an assertion.
  class CodePatcher {
   public:
    CodePatcher(byte* address, int size);
    virtual ~CodePatcher();
  
    // Macro assembler to emit code.
    MacroAssembler* masm() { return &masm_; }
  
   private:
    byte* address_;  // The address of the code being patched.
    int size_;  // Number of bytes of the expected patch size.
    MacroAssembler masm_;  // Macro assembler used to generate the code.
  };
  
  
  // -----------------------------------------------------------------------------
  // Static helper functions.
  
  // Generate an Operand for loading a field from an object.
  inline Operand FieldOperand(Register object, int offset) {
    return Operand(object, offset - kHeapObjectTag);
  }
  
  
  // Generate an Operand for loading an indexed field from an object.
  inline Operand FieldOperand(Register object,
                              Register index,
                              ScaleFactor scale,
                              int offset) {
    return Operand(object, index, scale, offset - kHeapObjectTag);
  }
  
  
  inline Operand FixedArrayElementOperand(Register array,
                                          Register index_as_smi,
                                          int additional_offset = 0) {
    int offset = FixedArray::kHeaderSize + additional_offset * kPointerSize;
    return FieldOperand(array, index_as_smi, times_half_pointer_size, offset);
  }
  
  
  inline Operand ContextOperand(Register context, int index) {
    return Operand(context, Context::SlotOffset(index));
  }
  
  
  inline Operand GlobalObjectOperand() {
    return ContextOperand(esi, Context::GLOBAL_OBJECT_INDEX);
  }
  
  
  #ifdef GENERATED_CODE_COVERAGE
  extern void LogGeneratedCodeCoverage(const char* file_line);
  #define CODE_COVERAGE_STRINGIFY(x) #x
  #define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
  #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
  #define ACCESS_MASM(masm) {                                               \
      byte* ia32_coverage_function =                                        \
          reinterpret_cast<byte*>(FUNCTION_ADDR(LogGeneratedCodeCoverage)); \
      masm->pushfd();                                                       \
      masm->pushad();                                                       \
      masm->push(Immediate(reinterpret_cast<int>(&__FILE_LINE__)));         \
      masm->call(ia32_coverage_function, RelocInfo::RUNTIME_ENTRY);         \
      masm->pop(eax);                                                       \
      masm->popad();                                                        \
      masm->popfd();                                                        \
    }                                                                       \
    masm->
  #else
  #define ACCESS_MASM(masm) masm->
  #endif
  
  
  } }  // namespace v8::internal
  
  #endif  // V8_X87_MACRO_ASSEMBLER_X87_H_
  