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 /* double gamma(double x)
14 * Return the logarithm of the Gamma function of x or the Gamma function of x,
15 * depending on the library mode.
16 */
17
18 #include <math.h>
19 #include "math_private.h"
20 #if defined(__UCLIBC_HAS_FENV__)
21 #include <errno.h>
22 #endif
23
24 double
tgamma(double x)25 tgamma(double x)
26 {
27 #if defined(__UCLIBC_HAS_FENV__)
28 double y = __ieee754_tgamma(x);
29
30 if(__builtin_expect (!isfinite (y) || y == 0, 0)
31 && (isfinite (x) || (isinf (x) && x < 0.0))
32 && _LIB_VERSION != _IEEE_) {
33 if (x == 0.0)
34 return __kernel_standard(x,x,50); /* tgamma pole */
35 else if(floor(x)==x&&x<0.0)
36 return __kernel_standard(x,x,41); /* tgamma domain */
37 else if (y == 0)
38 __set_errno (ERANGE); /* tgamma underflow */
39 else
40 return __kernel_standard(x,x,40); /* tgamma overflow */
41 }
42 return y;
43 #else
44 return __ieee754_tgamma(x);
45 #endif
46 }
47 libm_hidden_def(tgamma);
48