compiler/stdc/math/ld128/e_tgammal.c

   1 /*      $OpenBSD: e_tgammal.c,v 1.1 2011/07/06 00:02:42 martynas Exp $  */
   2
   3 /*
   4  * Copyright (c) 2011 Martynas Venckus <martynas@openbsd.org>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include "math.h"
  20
  21 #include "math_private.h"
  22
  23 long double
  24 tgammal(long double x)
  25 {
  26         int64_t i0,i1;
  27
  28         GET_LDOUBLE_WORDS64(i0,i1,x);
  29         if (((i0&0x7fffffffffffffffLL)|i1) == 0)
  30                 return (1.0/x);
  31
  32         if (i0<0 && (uint64_t)i0<0xffff000000000000ULL && rintl(x)==x)
  33                 return (x-x)/(x-x);
  34
  35         if (i0==0xffff000000000000ULL && i1==0)
  36                 return (x-x);
  37
  38         return expl(lgammal(x));
  39 }