| |
| /* @(#)w_gamma.c 1.3 95/01/18 */ |
| /* |
| * ==================================================== |
| * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Developed at SunSoft, a Sun Microsystems, Inc. business. |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| * |
| */ |
| |
| /* double ieee_gamma(double x) |
| * Return the logarithm of the Gamma function of x. |
| * |
| * Method: call gamma_r |
| */ |
| |
| #include "fdlibm.h" |
| |
| extern int signgam; |
| |
| #ifdef __STDC__ |
| double ieee_gamma(double x) |
| #else |
| double ieee_gamma(x) |
| double x; |
| #endif |
| { |
| #ifdef _IEEE_LIBM |
| return __ieee754_gamma_r(x,&signgam); |
| #else |
| double y; |
| y = __ieee754_gamma_r(x,&signgam); |
| if(_LIB_VERSION == _IEEE_) return y; |
| if(!ieee_finite(y)&&ieee_finite(x)) { |
| if(ieee_floor(x)==x&&x<=0.0) |
| return __kernel_standard(x,x,41); /* gamma pole */ |
| else |
| return __kernel_standard(x,x,40); /* gamma overflow */ |
| } else |
| return y; |
| #endif |
| } |