mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-14 17:11:06 +00:00
41bdb6e20c
2001-07-06 Paul Eggert <eggert@twinsun.com> * manual/argp.texi: Remove ignored LGPL copyright notice; it's not appropriate for documentation anyway. * manual/libc-texinfo.sh: "Library General Public License" -> "Lesser General Public License". 2001-07-06 Andreas Jaeger <aj@suse.de> * All files under GPL/LGPL version 2: Place under LGPL version 2.1.
57 lines
1.8 KiB
C
57 lines
1.8 KiB
C
/* Implementation of gamma function according to ISO C.
|
|
Copyright (C) 1997, 1999, 2001 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
|
|
|
|
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., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA. */
|
|
|
|
#include <math.h>
|
|
#include <math_private.h>
|
|
|
|
|
|
float
|
|
__ieee754_gammaf_r (float x, int *signgamp)
|
|
{
|
|
/* We don't have a real gamma implementation now. We'll use lgamma
|
|
and the exp function. But due to the required boundary
|
|
conditions we must check some values separately. */
|
|
int32_t hx;
|
|
|
|
GET_FLOAT_WORD (hx, x);
|
|
|
|
if ((hx & 0x7fffffff) == 0)
|
|
{
|
|
/* Return value for x == 0 is NaN with invalid exception. */
|
|
*signgamp = 0;
|
|
return x / x;
|
|
}
|
|
if (hx < 0 && (u_int32_t) hx < 0xff800000 && __rintf (x) == x)
|
|
{
|
|
/* Return value for integer x < 0 is NaN with invalid exception. */
|
|
*signgamp = 0;
|
|
return (x - x) / (x - x);
|
|
}
|
|
if (hx == 0xff800000)
|
|
{
|
|
/* x == -Inf. According to ISO this is NaN. */
|
|
*signgamp = 0;
|
|
return x - x;
|
|
}
|
|
|
|
/* XXX FIXME. */
|
|
return __ieee754_expf (__ieee754_lgammaf_r (x, signgamp));
|
|
}
|