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_FRAMES_X87_H_
  #define V8_X87_FRAMES_X87_H_
  
  namespace v8 {
  namespace internal {
  
  
  // Register lists
  // Note that the bit values must match those used in actual instruction encoding
  const int kNumRegs = 8;
  
  
  // Caller-saved registers
  const RegList kJSCallerSaved =
    1 << 0 |  // eax
    1 << 1 |  // ecx
    1 << 2 |  // edx
    1 << 3 |  // ebx - used as a caller-saved register in JavaScript code
    1 << 7;   // edi - callee function
  
  const int kNumJSCallerSaved = 5;
  
  
  // Number of registers for which space is reserved in safepoints.
  const int kNumSafepointRegisters = 8;
  
  const int kNoAlignmentPadding = 0;
  const int kAlignmentPaddingPushed = 2;
  const int kAlignmentZapValue = 0x12345678;  // Not heap object tagged.
  
  // ----------------------------------------------------
  
  
  class EntryFrameConstants : public AllStatic {
   public:
    static const int kCallerFPOffset      = -6 * kPointerSize;
  
    static const int kFunctionArgOffset   = +3 * kPointerSize;
    static const int kReceiverArgOffset   = +4 * kPointerSize;
    static const int kArgcOffset          = +5 * kPointerSize;
    static const int kArgvOffset          = +6 * kPointerSize;
  };
  
  
  class ExitFrameConstants : public AllStatic {
   public:
    static const int kFrameSize      = 2 * kPointerSize;
  
    static const int kCodeOffset     = -2 * kPointerSize;
    static const int kSPOffset       = -1 * kPointerSize;
  
    static const int kCallerFPOffset =  0 * kPointerSize;
    static const int kCallerPCOffset = +1 * kPointerSize;
  
    // FP-relative displacement of the caller's SP.  It points just
    // below the saved PC.
    static const int kCallerSPDisplacement = +2 * kPointerSize;
  
    static const int kConstantPoolOffset   = 0;  // Not used
  };
  
  
  class JavaScriptFrameConstants : public AllStatic {
   public:
    // FP-relative.
    static const int kLocal0Offset = StandardFrameConstants::kExpressionsOffset;
    static const int kLastParameterOffset = +2 * kPointerSize;
    static const int kFunctionOffset = StandardFrameConstants::kMarkerOffset;
  
    // Caller SP-relative.
    static const int kParam0Offset   = -2 * kPointerSize;
    static const int kReceiverOffset = -1 * kPointerSize;
  
    static const int kDynamicAlignmentStateOffset = kLocal0Offset;
  };
  
  
  inline Object* JavaScriptFrame::function_slot_object() const {
    const int offset = JavaScriptFrameConstants::kFunctionOffset;
    return Memory::Object_at(fp() + offset);
  }
  
  
  } }  // namespace v8::internal
  
  #endif  // V8_X87_FRAMES_X87_H_
  