math/w_tgammal.c

   1 /* w_gammal.c -- long double version of w_gamma.c.
   2  * Conversion to long double by Ulrich Drepper,
   3  * Cygnus Support, drepper@cygnus.com.
   4  */
   5
   6 /*
   7  * ====================================================
   8  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   9  *
  10  * Developed at SunPro, a Sun Microsystems, Inc. business.
  11  * Permission to use, copy, modify, and distribute this
  12  * software is freely granted, provided that this notice
  13  * is preserved.
  14  * ====================================================
  15  */
  16
  17 /* long double gammal(double x)
  18  * Return the Gamma function of x.
  19  */
  20
  21 #include <errno.h>
  22 #include <math.h>
  23 #include <math_private.h>
  24
  25 long double
  26 __tgammal(long double x)
  27 {
  28         int local_signgam;
  29         long double y = __ieee754_gammal_r(x,&local_signgam);
  30
  31         if(__glibc_unlikely (!isfinite (y) || y == 0)
  32            && (isfinite (x) || isinf (x) < 0)
  33            && _LIB_VERSION != _IEEE_) {
  34           if(x==0.0)
  35             return __kernel_standard_l(x,x,250); /* tgamma pole */
  36           else if(__floorl(x)==x&&x<0.0L)
  37             return __kernel_standard_l(x,x,241); /* tgamma domain */
  38           else if (y == 0)
  39             __set_errno (ERANGE); /* tgamma underflow */
  40           else
  41             return __kernel_standard_l(x,x,240); /* tgamma overflow */
  42         }
  43         return local_signgam < 0 ? - y : y;
  44 }
  45 weak_alias (__tgammal, tgammal)