Sprout/sprout/math/fma.hpp
2016-02-25 18:48:28 +09:00

86 lines
3 KiB
C++

/*=============================================================================
Copyright (c) 2011-2016 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#ifndef SPROUT_MATH_FMA_HPP
#define SPROUT_MATH_FMA_HPP
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/limits.hpp>
#include <sprout/math/detail/config.hpp>
#include <sprout/math/isnan.hpp>
#include <sprout/math/isinf.hpp>
#include <sprout/math/signbit.hpp>
#include <sprout/type_traits/float_promote.hpp>
#include <sprout/type_traits/enabler_if.hpp>
namespace sprout {
namespace math {
namespace detail {
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
inline SPROUT_CONSTEXPR float
builtin_fma(float x, float y, float z) {
return __builtin_fmaf(x, y, z);
}
inline SPROUT_CONSTEXPR double
builtin_fma(double x, double y, double z) {
return __builtin_fma(x, y, z);
}
inline SPROUT_CONSTEXPR long double
builtin_fma(long double x, long double y, long double z) {
return __builtin_fmal(x, y, z);
}
#endif
} // namespace detail
//
// fma
//
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR FloatType
fma(FloatType x, FloatType y, FloatType z) {
return sprout::math::isnan(x) ? x
: sprout::math::isnan(y) ? y
: sprout::math::isnan(z) ? z
: sprout::math::isinf(x) && y == 0 ? sprout::numeric_limits<FloatType>::quiet_NaN()
: sprout::math::isinf(y) && x == 0 ? sprout::numeric_limits<FloatType>::quiet_NaN()
: (sprout::math::isinf(x) || sprout::math::isinf(y)) && sprout::math::isinf(z) && (sprout::math::signbit(x) ^ sprout::math::signbit(y) ^ sprout::math::signbit(z))
? sprout::numeric_limits<FloatType>::quiet_NaN()
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
: sprout::math::detail::builtin_fma(x, y, z)
#else
: x * y + z
#endif
;
}
template<
typename ArithmeticType1,
typename ArithmeticType2,
typename ArithmeticType3,
typename sprout::enabler_if<
std::is_arithmetic<ArithmeticType1>::value
&& std::is_arithmetic<ArithmeticType2>::value
&& std::is_arithmetic<ArithmeticType3>::value
>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR typename sprout::float_promote<
ArithmeticType1, ArithmeticType2, ArithmeticType3
>::type
fma(ArithmeticType1 x, ArithmeticType2 y, ArithmeticType3 z) {
typedef typename sprout::float_promote<
ArithmeticType1, ArithmeticType2, ArithmeticType3
>::type type;
return sprout::math::fma(static_cast<type>(x), static_cast<type>(y), static_cast<type>(z));
}
} // namespace math
using sprout::math::fma;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_FMA_HPP