compiler/mlib/w_lgamma.c

   1 /* @(#)w_lgamma.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 #ifndef lint
  14 static char rcsid[] = "$FreeBSD: src/lib/msun/src/w_lgamma.c,v 1.5 1999/08/28 00:07:04 peter Exp $";
  15 #endif
  16
  17 /* double lgamma(double x)
  18  * Return the logarithm of the Gamma function of x.
  19  *
  20  * Method: call __ieee754_lgamma_r
  21  */
  22
  23 #include "math.h"
  24 #include "math_private.h"
  25
  26 extern int signgam;
  27
  28 #ifdef __STDC__
  29         double lgamma(double x)
  30 #else
  31         double lgamma(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,15); /* lgamma pole */
  44             else
  45                 return __kernel_standard(x,x,14); /* lgamma overflow */
  46         } else
  47             return y;
  48 #endif
  49 }