Line data    Source code

       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             : 
      12             : namespace v8 {
      13             : namespace 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.
      19             : class 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         232 :   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             : 
      54             : ASSERT_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
      59             : class 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         324 :   uint64_t get_bits() const { return bit_pattern_; }
      72             :   double get_scalar() const { return bit_cast<double>(bit_pattern_); }
      73       14251 :   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             : 
      93             : ASSERT_TRIVIALLY_COPYABLE(Float64);
      94             : 
      95             : }  // namespace internal
      96             : }  // namespace v8
      97             : 
      98             : #endif  // V8_BOXED_FLOAT_H_