blob: 15e821e966a749580ce9666cea9bf78d91460ea4 [file] [log] [blame]
// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/objects/heap-object.h"
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
namespace v8 {
namespace internal {
// The HeapNumber class describes heap allocated numbers that cannot be
// represented in a Smi (small integer). MutableHeapNumber is the same, but its
// number value can change over time (it is used only as property storage).
// HeapNumberBase merely exists to avoid code duplication.
class HeapNumberBase : public HeapObject {
// [value]: number value.
inline double value() const;
inline void set_value(double value);
inline uint64_t value_as_bits() const;
inline void set_value_as_bits(uint64_t bits);
inline int get_exponent();
inline int get_sign();
// Layout description.
static const int kValueOffset = HeapObject::kHeaderSize;
// IEEE doubles are two 32 bit words. The first is just mantissa, the second
// is a mixture of sign, exponent and mantissa. The offsets of two 32 bit
// words within double numbers are endian dependent and they are set
// accordingly.
static const int kMantissaOffset = kValueOffset;
static const int kExponentOffset = kValueOffset + 4;
#elif defined(V8_TARGET_BIG_ENDIAN)
static const int kMantissaOffset = kValueOffset + 4;
static const int kExponentOffset = kValueOffset;
#error Unknown byte ordering
static const int kSize = kValueOffset + kDoubleSize;
static const uint32_t kSignMask = 0x80000000u;
static const uint32_t kExponentMask = 0x7ff00000u;
static const uint32_t kMantissaMask = 0xfffffu;
static const int kMantissaBits = 52;
static const int kExponentBits = 11;
static const int kExponentBias = 1023;
static const int kExponentShift = 20;
static const int kInfinityOrNanExponent =
(kExponentMask >> kExponentShift) - kExponentBias;
static const int kMantissaBitsInTopWord = 20;
static const int kNonMantissaBitsInTopWord = 12;
// Just to make the macro-generated constructor happy. Subclasses should
// perform their own proper type checking.
inline bool IsHeapNumberBase() const { return true; }
OBJECT_CONSTRUCTORS(HeapNumberBase, HeapObject);
class HeapNumber : public HeapNumberBase {
V8_EXPORT_PRIVATE void HeapNumberPrint(std::ostream& os);
OBJECT_CONSTRUCTORS(HeapNumber, HeapNumberBase);
class MutableHeapNumber : public HeapNumberBase {
V8_EXPORT_PRIVATE void MutableHeapNumberPrint(std::ostream& os);
OBJECT_CONSTRUCTORS(MutableHeapNumber, HeapNumberBase);
} // namespace internal
} // namespace v8
#include "src/objects/object-macros-undef.h"