/* 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 , 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 #include long double __ieee754_gammal_r (long double 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. */ u_int32_t es, hx, lx; GET_LDOUBLE_WORDS (es, hx, lx, x); if (((es & 0x7fff) | hx | lx) == 0) /* Return value for x == 0 is NaN with invalid exception. */ return x / x; if ((hx & 0x8000) != 0 && (hx & 0x7fff) != 0x7fff && __rintl (x) == x) { /* Return value for integer x < 0 is NaN with invalid exception. */ return (x - x) / (x - x); } /* XXX FIXME. */ return __ieee754_expl (__ieee754_lgammal_r (x, signgamp)); }