| /* @(#)w_gamma.c 5.1 93/09/24 */ |
| /* |
| * ==================================================== |
| * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Developed at SunPro, a Sun Microsystems, Inc. business. |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| */ |
| |
| /* double gamma(double x) |
| * Return the logarithm of the Gamma function of x or the Gamma function of x, |
| * depending on the library mode. |
| */ |
| |
| #include <errno.h> |
| #include <math.h> |
| #include <math_private.h> |
| |
| double |
| __tgamma(double x) |
| { |
| int local_signgam; |
| double y = __ieee754_gamma_r(x,&local_signgam); |
| |
| if(__glibc_unlikely (!isfinite (y) || y == 0) |
| && (isfinite (x) || (isinf (x) && x < 0.0)) |
| && _LIB_VERSION != _IEEE_) { |
| if (x == 0.0) |
| return __kernel_standard(x,x,50); /* tgamma pole */ |
| else if(__floor(x)==x&&x<0.0) |
| return __kernel_standard(x,x,41); /* tgamma domain */ |
| else if (y == 0) |
| __set_errno (ERANGE); /* tgamma underflow */ |
| else |
| return __kernel_standard(x,x,40); /* tgamma overflow */ |
| } |
| return local_signgam < 0 ? -y : y; |
| } |
| weak_alias (__tgamma, tgamma) |
| #ifdef NO_LONG_DOUBLE |
| strong_alias (__tgamma, __tgammal) |
| weak_alias (__tgamma, tgammal) |
| #endif |