mirror of
git://sourceware.org/git/glibc.git
synced 2024-12-03 04:01:43 +08:00
47 lines
1.5 KiB
C
47 lines
1.5 KiB
C
|
/* Check `long double' for Infinity. i386 FPU version.
|
||
|
|
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 Library General Public License as
|
||
|
|
published by the Free Software Foundation; either version 2 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
|
||
|
|
Library General Public License for more details.
|
||
|
|
|
||
|
|
You should have received a copy of the GNU Library General Public
|
||
|
|
License along with the GNU C Library; see the file COPYING.LIB. If
|
||
|
|
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
|
||
|
|
Cambridge, MA 02139, USA. */
|
||
|
|
|
||
|
|
#include <math.h>
|
||
|
|
#include "ieee754.h"
|
||
|
|
|
||
|
|
#undef __isinfl
|
||
|
|
#undef isinfl
|
||
|
|
|
||
|
|
|
||
|
|
/* Return 0 if VALUE is finite or NaN, +1 if it
|
||
|
|
is +Infinity, -1 if it is -Infinity. */
|
||
|
|
int
|
||
|
|
__isinfl (long double value)
|
||
|
|
{
|
||
|
|
union ieee854_long_double u;
|
||
|
|
|
||
|
|
u.d = value;
|
||
|
|
|
||
|
|
/* Intel's interpretation of the IEEE 854 standard defines Inf to
|
||
|
|
have the maximum possible exponent and the MSB of the mantissa
|
||
|
|
set. No further bit of the mantissa must be set. */
|
||
|
|
if ((u.ieee.exponent & 0x7fff) == 0x7fff &&
|
||
|
|
u.ieee.mantissa0 == 0x80000000 && u.ieee.mantissa1 == 0)
|
||
|
|
return u.ieee.negative ? -1 : 1;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
weak_alias (__isinfl, isinfl);
|