sysdeps/libm-ieee754/w_gamma.c

   1 /* @(#)w_gamma.c 5.1 93/09/24 */
   2 /*
   3  * ====================================================
   4  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   5  *
   6  * Developed at SunPro, a Sun Microsystems, Inc. business.
   7  * Permission to use, copy, modify, and distribute this
   8  * software is freely granted, provided that this notice
   9  * is preserved.
  10  * ====================================================
  11  */
  12
  13 #if defined(LIBM_SCCS) && !defined(lint)
  14 static char rcsid[] = "$NetBSD: w_gamma.c,v 1.7 1995/11/20 22:06:43 jtc Exp $";
  15 #endif
  16
  17 /* double gamma(double x)
  18  * Return the logarithm of the Gamma function of x.
  19  *
  20  * Method: call gamma_r
  21  */
  22
  23 #include "math.h"
  24 #include "math_private.h"
  25
  26 extern int signgam;
  27
  28 #ifdef __STDC__
  29         double __gamma(double x)
  30 #else
  31         double __gamma(x)
  32         double x;
  33 #endif
  34 {
  35 #ifdef _IEEE_LIBM
  36         return __ieee754_lgamma_r(x,&signgam);
  37 #else
  38         double y;
  39         y = __ieee754_lgamma_r(x,&signgam);
  40         if(_LIB_VERSION == _IEEE_) return y;
  41         if(!__finite(y)&&__finite(x)) {
  42             if(__floor(x)==x&&x<=0.0)
  43                 return __kernel_standard(x,x,41); /* gamma pole */
  44             else
  45                 return __kernel_standard(x,x,40); /* gamma overflow */
  46         } else
  47             return y;
  48 #endif
  49 }
  50 weak_alias (__gamma, gamma)
  51 #ifdef NO_LONG_DOUBLE
  52 strong_alias (__gamma, __gammal)
  53 weak_alias (__gamma, gammal)
  54 #endif