| // 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. |
| |
| #ifndef V8_OBJECTS_HEAP_NUMBER_H_ |
| #define V8_OBJECTS_HEAP_NUMBER_H_ |
| |
| #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 { |
| public: |
| // [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. |
| #if defined(V8_TARGET_LITTLE_ENDIAN) |
| 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; |
| #else |
| #error Unknown byte ordering |
| #endif |
| |
| 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 { |
| public: |
| DECL_CAST(HeapNumber) |
| V8_EXPORT_PRIVATE void HeapNumberPrint(std::ostream& os); |
| |
| OBJECT_CONSTRUCTORS(HeapNumber, HeapNumberBase); |
| }; |
| |
| class MutableHeapNumber : public HeapNumberBase { |
| public: |
| DECL_CAST(MutableHeapNumber) |
| V8_EXPORT_PRIVATE void MutableHeapNumberPrint(std::ostream& os); |
| |
| OBJECT_CONSTRUCTORS(MutableHeapNumber, HeapNumberBase); |
| }; |
| |
| } // namespace internal |
| } // namespace v8 |
| |
| #include "src/objects/object-macros-undef.h" |
| |
| #endif // V8_OBJECTS_HEAP_NUMBER_H_ |