mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-11 05:40:06 +00:00
52495f29a2
Update. 2004-11-20 Jakub Jelinek <jakub@redhat.com> * sysdeps/ieee754/k_standard.c: Document code 50. (__kernel_standard) <case 50>: Avoid raising div-by-zero exception again. 2004-11-19 H.J. Lu <hongjiu.lu@intel.com> [BZ #552] * math/libm-test.inc (tgamma_test): Update tgamma (0) and tgamma (-0). * sysdeps/generic/w_tgamma.c (__tgamma): Properly handle |x| == 0. * sysdeps/generic/w_tgammaf.c (__tgammaf): Likewise. * sysdeps/generic/w_tgammal.c (__tgammal): Likewise. * sysdeps/ieee754/dbl-64/e_gamma_r.c (__ieee754_gamma_r): Likewise. * sysdeps/ieee754/flt-32/e_gammaf_r.c: Likewise. * sysdeps/ieee754/ldbl-128/e_gammal_r.c: Likewise. * sysdeps/ieee754/ldbl-96/e_gammal_r.c: Likewise. * sysdeps/ieee754/k_standard.c (__kernel_standard): Handle tgamma (0) and tgamma (-0).
57 lines
1.9 KiB
C
57 lines
1.9 KiB
C
/* Implementation of gamma function according to ISO C.
|
|
Copyright (C) 1997, 1999, 2001, 2004 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 Inf with divide by zero exception. */
|
|
*signgamp = 0;
|
|
return 1.0 / 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));
|
|
}
|