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back to std::bit_cast

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This commit is contained in:
Anders Dalvander 2024-12-03 23:20:45 +01:00
parent 3b9ff76143
commit da819feb74
2 changed files with 63 additions and 49 deletions
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2
include/fast_float/digit_comparison.h
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@ -72,7 +72,7 @@ to_extended(T value) noexcept {
binary_format<T>::minimum_exponent(); binary_format<T>::minimum_exponent();
equiv_uint bits; equiv_uint bits;
#if FASTFLOAT_HAS_BIT_CAST #if FASTFLOAT_HAS_BIT_CAST
bits = bit_cast<equiv_uint>(value); bits = std::bit_cast<equiv_uint>(value);
#else #else
::memcpy(&bits, &value, sizeof(T)); ::memcpy(&bits, &value, sizeof(T));
#endif #endif

110
include/fast_float/float_common.h
View File

@ -260,6 +260,7 @@ struct is_supported_char_type
> { > {
}; };
#if 0
union float_union { union float_union {
float f; float f;
uint32_t bits; uint32_t bits;
@ -341,6 +342,7 @@ fastfloat_really_inline constexpr std::bfloat16_t bit_cast(const uint16_t &u) {
return fu.f; return fu.f;
} }
#endif // __STDCPP_BFLOAT16_T__ #endif // __STDCPP_BFLOAT16_T__
#endif // 0
// Compares two ASCII strings in a case insensitive manner. // Compares two ASCII strings in a case insensitive manner.
template <typename UC> template <typename UC>
@ -519,25 +521,25 @@ template <typename T, typename U = void> struct binary_format_lookup_tables;
template <typename T> struct binary_format : binary_format_lookup_tables<T> { template <typename T> struct binary_format : binary_format_lookup_tables<T> {
using equiv_uint = equiv_uint_t<T>; using equiv_uint = equiv_uint_t<T>;
static inline constexpr int mantissa_explicit_bits(); static constexpr int mantissa_explicit_bits();
static inline constexpr int minimum_exponent(); static constexpr int minimum_exponent();
static inline constexpr int infinite_power(); static constexpr int infinite_power();
static inline constexpr int sign_index(); static constexpr int sign_index();
static inline constexpr int static constexpr int
min_exponent_fast_path(); // used when fegetround() == FE_TONEAREST min_exponent_fast_path(); // used when fegetround() == FE_TONEAREST
static inline constexpr int max_exponent_fast_path(); static constexpr int max_exponent_fast_path();
static inline constexpr int max_exponent_round_to_even(); static constexpr int max_exponent_round_to_even();
static inline constexpr int min_exponent_round_to_even(); static constexpr int min_exponent_round_to_even();
static inline constexpr uint64_t max_mantissa_fast_path(int64_t power); static constexpr uint64_t max_mantissa_fast_path(int64_t power);
static inline constexpr uint64_t static constexpr uint64_t
max_mantissa_fast_path(); // used when fegetround() == FE_TONEAREST max_mantissa_fast_path(); // used when fegetround() == FE_TONEAREST
static inline constexpr int largest_power_of_ten(); static constexpr int largest_power_of_ten();
static inline constexpr int smallest_power_of_ten(); static constexpr int smallest_power_of_ten();
static inline constexpr T exact_power_of_ten(int64_t power); static constexpr T exact_power_of_ten(int64_t power);
static inline constexpr size_t max_digits(); static constexpr size_t max_digits();
static inline constexpr equiv_uint exponent_mask(); static constexpr equiv_uint exponent_mask();
static inline constexpr equiv_uint mantissa_mask(); static constexpr equiv_uint mantissa_mask();
static inline constexpr equiv_uint hidden_bit_mask(); static constexpr equiv_uint hidden_bit_mask();
}; };
template <typename U> struct binary_format_lookup_tables<double, U> { template <typename U> struct binary_format_lookup_tables<double, U> {
@ -710,6 +712,11 @@ inline constexpr uint64_t binary_format<double>::max_mantissa_fast_path() {
return uint64_t(2) << mantissa_explicit_bits(); return uint64_t(2) << mantissa_explicit_bits();
} }
template <>
inline constexpr uint64_t binary_format<float>::max_mantissa_fast_path() {
return uint64_t(2) << mantissa_explicit_bits();
}
// credit: Jakub Jelínek // credit: Jakub Jelínek
#ifdef __STDCPP_FLOAT16_T__ #ifdef __STDCPP_FLOAT16_T__
template <typename U> struct binary_format_lookup_tables<std::float16_t, U> { template <typename U> struct binary_format_lookup_tables<std::float16_t, U> {
@ -768,6 +775,11 @@ inline constexpr int binary_format<std::float16_t>::max_exponent_fast_path() {
return 4; return 4;
} }
template <>
inline constexpr int binary_format<std::float16_t>::mantissa_explicit_bits() {
return 10;
}
template <> template <>
inline constexpr uint64_t inline constexpr uint64_t
binary_format<std::float16_t>::max_mantissa_fast_path() { binary_format<std::float16_t>::max_mantissa_fast_path() {
@ -790,43 +802,43 @@ inline constexpr int binary_format<std::float16_t>::min_exponent_fast_path() {
} }
template <> template <>
constexpr int binary_format<std::float16_t>::mantissa_explicit_bits() { inline constexpr int
return 10; binary_format<std::float16_t>::max_exponent_round_to_even() {
}
template <>
constexpr int binary_format<std::float16_t>::max_exponent_round_to_even() {
return 5; return 5;
} }
template <> template <>
constexpr int binary_format<std::float16_t>::min_exponent_round_to_even() { inline constexpr int
binary_format<std::float16_t>::min_exponent_round_to_even() {
return -22; return -22;
} }
template <> constexpr int binary_format<std::float16_t>::minimum_exponent() { template <>
inline constexpr int binary_format<std::float16_t>::minimum_exponent() {
return -15; return -15;
} }
template <> constexpr int binary_format<std::float16_t>::infinite_power() { template <>
inline constexpr int binary_format<std::float16_t>::infinite_power() {
return 0x1F; return 0x1F;
} }
template <> constexpr int binary_format<std::float16_t>::sign_index() { template <> inline constexpr int binary_format<std::float16_t>::sign_index() {
return 15; return 15;
} }
template <> template <>
constexpr int binary_format<std::float16_t>::largest_power_of_ten() { inline constexpr int binary_format<std::float16_t>::largest_power_of_ten() {
return 4; return 4;
} }
template <> template <>
constexpr int binary_format<std::float16_t>::smallest_power_of_ten() { inline constexpr int binary_format<std::float16_t>::smallest_power_of_ten() {
return -27; return -27;
} }
template <> constexpr size_t binary_format<std::float16_t>::max_digits() { template <>
inline constexpr size_t binary_format<std::float16_t>::max_digits() {
return 22; return 22;
} }
@ -887,6 +899,11 @@ binary_format<std::bfloat16_t>::hidden_bit_mask() {
return 0x0080; return 0x0080;
} }
template <>
inline constexpr int binary_format<std::bfloat16_t>::mantissa_explicit_bits() {
return 7;
}
template <> template <>
inline constexpr uint64_t inline constexpr uint64_t
binary_format<std::bfloat16_t>::max_mantissa_fast_path() { binary_format<std::bfloat16_t>::max_mantissa_fast_path() {
@ -909,43 +926,43 @@ inline constexpr int binary_format<std::bfloat16_t>::min_exponent_fast_path() {
} }
template <> template <>
constexpr int binary_format<std::bfloat16_t>::mantissa_explicit_bits() { inline constexpr int
return 7; binary_format<std::bfloat16_t>::max_exponent_round_to_even() {
}
template <>
constexpr int binary_format<std::bfloat16_t>::max_exponent_round_to_even() {
return 3; return 3;
} }
template <> template <>
constexpr int binary_format<std::bfloat16_t>::min_exponent_round_to_even() { inline constexpr int
binary_format<std::bfloat16_t>::min_exponent_round_to_even() {
return -24; return -24;
} }
template <> constexpr int binary_format<std::bfloat16_t>::minimum_exponent() { template <>
inline constexpr int binary_format<std::bfloat16_t>::minimum_exponent() {
return -127; return -127;
} }
template <> constexpr int binary_format<std::bfloat16_t>::infinite_power() { template <>
inline constexpr int binary_format<std::bfloat16_t>::infinite_power() {
return 0xFF; return 0xFF;
} }
template <> constexpr int binary_format<std::bfloat16_t>::sign_index() { template <> inline constexpr int binary_format<std::bfloat16_t>::sign_index() {
return 15; return 15;
} }
template <> template <>
constexpr int binary_format<std::bfloat16_t>::largest_power_of_ten() { inline constexpr int binary_format<std::bfloat16_t>::largest_power_of_ten() {
return 38; return 38;
} }
template <> template <>
constexpr int binary_format<std::bfloat16_t>::smallest_power_of_ten() { inline constexpr int binary_format<std::bfloat16_t>::smallest_power_of_ten() {
return -60; return -60;
} }
template <> constexpr size_t binary_format<std::bfloat16_t>::max_digits() { template <>
inline constexpr size_t binary_format<std::bfloat16_t>::max_digits() {
return 98; return 98;
} }
@ -961,11 +978,6 @@ binary_format<double>::max_mantissa_fast_path(int64_t power) {
return (void)max_mantissa[0], max_mantissa[power]; return (void)max_mantissa[0], max_mantissa[power];
} }
template <>
inline constexpr uint64_t binary_format<float>::max_mantissa_fast_path() {
return uint64_t(2) << mantissa_explicit_bits();
}
template <> template <>
inline constexpr uint64_t inline constexpr uint64_t
binary_format<float>::max_mantissa_fast_path(int64_t power) { binary_format<float>::max_mantissa_fast_path(int64_t power) {
@ -1064,6 +1076,7 @@ to_float(bool negative, adjusted_mantissa am, T &value) {
#endif #endif
} }
#if 0
#ifdef __STDCPP_FLOAT16_T__ #ifdef __STDCPP_FLOAT16_T__
template <> template <>
fastfloat_really_inline void to_float<std::float16_t>(bool negative, fastfloat_really_inline void to_float<std::float16_t>(bool negative,
@ -1091,6 +1104,7 @@ fastfloat_really_inline void to_float<std::bfloat16_t>(bool negative,
} }
#endif // __STDCPP_BFLOAT16_T__ #endif // __STDCPP_BFLOAT16_T__
#endif // 0
template <typename = void> struct space_lut { template <typename = void> struct space_lut {
static constexpr bool value[] = { static constexpr bool value[] = {