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Add fpclassify.

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This commit is contained in:
Peter Dimov
2020-12-24 00:58:56 +02:00
parent c307f86520
commit bee040b8cc
2 changed files with 93 additions and 0 deletions
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73
include/boost/core/cmath.hpp
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@@ -70,12 +70,85 @@ template<class T> bool signbit( T x )
return _copysign( 1.0, static_cast<double>( x ) ) < 0.0;
}
int const fp_zero = 0;
int const fp_subnormal = 1;
int const fp_normal = 2;
int const fp_infinite = 3;
int const fp_nan = 4;
inline int fpclassify( float x )
{
switch( _fpclass( x ) )
{
case _FPCLASS_SNAN:
case _FPCLASS_QNAN:
return fp_nan;
case _FPCLASS_NINF:
case _FPCLASS_PINF:
return fp_infinite;
case _FPCLASS_NZ:
case _FPCLASS_PZ:
return fp_zero;
default:
return boost::core::isnormal( x )? fp_normal: fp_subnormal;
}
}
inline int fpclassify( double x )
{
switch( _fpclass( x ) )
{
case _FPCLASS_SNAN:
case _FPCLASS_QNAN:
return fp_nan;
case _FPCLASS_NINF:
case _FPCLASS_PINF:
return fp_infinite;
case _FPCLASS_NZ:
case _FPCLASS_PZ:
return fp_zero;
case _FPCLASS_ND:
case _FPCLASS_PD:
return fp_subnormal;
default:
return fp_normal;
}
}
inline int fpclassify( long double x )
{
return boost::core::fpclassify( static_cast<double>( x ) );
}
#else
using std::isfinite;
using std::isnan;
using std::isinf;
using std::isnormal;
using std::fpclassify;
int const fp_zero = FP_ZERO;
int const fp_subnormal = FP_SUBNORMAL;
int const fp_normal = FP_NORMAL;
int const fp_infinite = FP_INFINITE;
int const fp_nan = FP_NAN;
using std::signbit;