1// Copyright 2017 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef V8_BOXED_FLOAT_H_
6#define V8_BOXED_FLOAT_H_
7
8#include <cmath>
9#include "src/base/macros.h"
10#include "src/globals.h"
11
12namespace v8 {
13namespace internal {
14
15// TODO(ahaas): Make these classes with the one in double.h
16
17// Safety wrapper for a 32-bit floating-point value to make sure we don't lose
18// the exact bit pattern during deoptimization when passing this value.
19class Float32 {
20 public:
21 Float32() = default;
22
23 // This constructor does not guarantee that bit pattern of the input value
24 // is preserved if the input is a NaN.
25 explicit Float32(float value) : bit_pattern_(bit_cast<uint32_t>(value)) {
26 // Check that the provided value is not a NaN, because the bit pattern of a
27 // NaN may be changed by a bit_cast, e.g. for signalling NaNs on ia32.
28 DCHECK(!std::isnan(value));
29 }
30
31 uint32_t get_bits() const { return bit_pattern_; }
32
33 float get_scalar() const { return bit_cast<float>(bit_pattern_); }
34
35 bool is_nan() const {
36 // Even though {get_scalar()} might flip the quiet NaN bit, it's ok here,
37 // because this does not change the is_nan property.
38 return std::isnan(get_scalar());
39 }
40
41 // Return a pointer to the field storing the bit pattern. Used in code
42 // generation tests to store generated values there directly.
43 uint32_t* get_bits_address() { return &bit_pattern_; }
44
45 static constexpr Float32 FromBits(uint32_t bits) { return Float32(bits); }
46
47 private:
48 uint32_t bit_pattern_ = 0;
49
50 explicit constexpr Float32(uint32_t bit_pattern)
51 : bit_pattern_(bit_pattern) {}
52};
53
54ASSERT_TRIVIALLY_COPYABLE(Float32);
55
56// Safety wrapper for a 64-bit floating-point value to make sure we don't lose
57// the exact bit pattern during deoptimization when passing this value.
58// TODO(ahaas): Unify this class with Double in double.h
59class Float64 {
60 public:
61 Float64() = default;
62
63 // This constructor does not guarantee that bit pattern of the input value
64 // is preserved if the input is a NaN.
65 explicit Float64(double value) : bit_pattern_(bit_cast<uint64_t>(value)) {
66 // Check that the provided value is not a NaN, because the bit pattern of a
67 // NaN may be changed by a bit_cast, e.g. for signalling NaNs on ia32.
68 DCHECK(!std::isnan(value));
69 }
70
71 uint64_t get_bits() const { return bit_pattern_; }
72 double get_scalar() const { return bit_cast<double>(bit_pattern_); }
73 bool is_hole_nan() const { return bit_pattern_ == kHoleNanInt64; }
74 bool is_nan() const {
75 // Even though {get_scalar()} might flip the quiet NaN bit, it's ok here,
76 // because this does not change the is_nan property.
77 return std::isnan(get_scalar());
78 }
79
80 // Return a pointer to the field storing the bit pattern. Used in code
81 // generation tests to store generated values there directly.
82 uint64_t* get_bits_address() { return &bit_pattern_; }
83
84 static constexpr Float64 FromBits(uint64_t bits) { return Float64(bits); }
85
86 private:
87 uint64_t bit_pattern_ = 0;
88
89 explicit constexpr Float64(uint64_t bit_pattern)
90 : bit_pattern_(bit_pattern) {}
91};
92
93ASSERT_TRIVIALLY_COPYABLE(Float64);
94
95} // namespace internal
96} // namespace v8
97
98#endif // V8_BOXED_FLOAT_H_
99