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Change fp_traits to handle sign manipulation separately from fp-classification.

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Fixes some Linux/GCC regressions but not yet all.

[SVN r71405]
This commit is contained in:
John Maddock
2011-04-21 18:11:37 +00:00
parent 15c9b19ac1
commit 7f1a45870a
2 changed files with 13 additions and 20 deletions
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3
include/boost/math/special_functions/detail/fp_traits.hpp
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@@ -552,12 +552,13 @@ struct select_native<long double>
template<class T> struct fp_traits
{
typedef BOOST_DEDUCED_TYPENAME size_to_precision<sizeof(T), ::boost::is_floating_point<T>::value>::type precision;
#if defined(BOOST_MATH_USE_STD_FPCLASSIFY) && !defined(BOOST_MATH_DISABLE_STD_FPCLASSIFY)
typedef typename select_native<T>::type type;
#else
typedef BOOST_DEDUCED_TYPENAME size_to_precision<sizeof(T), ::boost::is_floating_point<T>::value>::type precision;
typedef fp_traits_non_native<T, precision> type;
#endif
typedef fp_traits_non_native<T, precision> sign_change_type;
};
//------------------------------------------------------------------------------

30
include/boost/math/special_functions/sign.hpp
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@@ -66,14 +66,6 @@ namespace detail {
// Changesign
#ifdef BOOST_MATH_USE_STD_FPCLASSIFY
template<class T>
inline int changesign_impl(T x, native_tag const&)
{
return -x;
}
#endif
template<class T>
inline T (changesign_impl)(T x, generic_tag<true> const&)
{
@@ -90,7 +82,7 @@ namespace detail {
template<class T>
inline T changesign_impl(T x, ieee_copy_all_bits_tag const&)
{
typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits;
typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::sign_change_type traits;
BOOST_DEDUCED_TYPENAME traits::bits a;
traits::get_bits(x,a);
@@ -102,7 +94,7 @@ namespace detail {
template<class T>
inline T (changesign_impl)(T x, ieee_copy_leading_bits_tag const&)
{
typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits;
typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::sign_change_type traits;
BOOST_DEDUCED_TYPENAME traits::bits a;
traits::get_bits(x,a);
@@ -115,7 +107,7 @@ namespace detail {
} // namespace detail
template<class T> int (signbit)(T x)
{ //!< \brief return true if floating-point type T is NaN (Not A Number).
{
typedef typename detail::fp_traits<T>::type traits;
typedef typename traits::method method;
typedef typename boost::is_floating_point<T>::type fp_tag;
@@ -128,22 +120,22 @@ inline int sign BOOST_NO_MACRO_EXPAND(const T& z)
return (z == 0) ? 0 : (boost::math::signbit)(z) ? -1 : 1;
}
template <class T>
inline T copysign BOOST_NO_MACRO_EXPAND(const T& x, const T& y)
{
BOOST_MATH_STD_USING
return fabs(x) * ((boost::math::signbit)(y) ? -1 : 1);
}
template<class T> T (changesign)(T x)
{ //!< \brief return unchanged binary pattern of x, except for change of sign bit.
typedef typename detail::fp_traits<T>::type traits;
typedef typename detail::fp_traits<T>::sign_change_type traits;
typedef typename traits::method method;
typedef typename boost::is_floating_point<T>::type fp_tag;
return detail::changesign_impl(x, method());
}
template <class T>
inline T copysign BOOST_NO_MACRO_EXPAND(const T& x, const T& y)
{
BOOST_MATH_STD_USING
return (boost::math::signbit)(x) != (boost::math::signbit)(y) ? (boost::math::changesign)(x) : x;
}
} // namespace math
} // namespace boost