reactos/lib/sdk/crt/float/isnan.c
Timo Kreuzer 49d7aed889 Merge to trunk head (r46631)
svn path=/branches/reactos-yarotows/; revision=46633
2010-04-01 02:52:00 +00:00

98 lines
2.2 KiB
C

/* Copyright (C) 1991, 1992, 1995 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include <precomp.h>
/*
* @implemented
*/
int _isnan(double __x)
{
union
{
double* __x;
double_s* x;
} x;
x.__x = &__x;
return ( x.x->exponent == 0x7ff && ( x.x->mantissah != 0 || x.x->mantissal != 0 ));
}
int _isnanl(long double __x)
{
/* Intel's extended format has the normally implicit 1 explicit
present. Sigh! */
union
{
long double* __x;
long_double_s* x;
} x;
x.__x = &__x;
/* IEEE 854 NaN's have the maximum possible
exponent and a nonzero mantissa. */
return (( x.x->exponent == 0x7fff)
&& ( (x.x->mantissah & 0x80000000) != 0)
&& ( (x.x->mantissah & (unsigned int)0x7fffffff) != 0 || x.x->mantissal != 0 ));
}
int _isinf(double __x)
{
union
{
double* __x;
double_s* x;
} x;
x.__x = &__x;
return ( x.x->exponent == 0x7ff && ( x.x->mantissah == 0 && x.x->mantissal == 0 ));
}
/*
* @implemented
*/
int _finite( double x )
{
return !_isinf(x);
}
int _isinfl(long double __x)
{
/* Intel's extended format has the normally implicit 1 explicit
present. Sigh! */
union
{
long double* __x;
long_double_s* x;
} x;
x.__x = &__x;
/* An IEEE 854 infinity has an exponent with the
maximum possible value and a zero mantissa. */
if ( x.x->exponent == 0x7fff && ( (x.x->mantissah == 0x80000000 ) && x.x->mantissal == 0 ))
return x.x->sign ? -1 : 1;
return 0;
}