| /* Implementation of gamma function according to ISO C. |
| Copyright (C) 1997 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 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., 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. */ |
| 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. */ |
| return (x - x) / (x - x); |
| } |
| |
| /* XXX FIXME. */ |
| return __ieee754_expf (__ieee754_lgammaf_r (x, signgamp)); |
| } |