1
2 /* @(#)e_tgamma.c 5.1 93/09/24 */
3 /*
4 * ====================================================
5 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6 *
7 * Developed at SunPro, a Sun Microsystems, Inc. business.
8 * Permission to use, copy, modify, and distribute this
9 * software is freely granted, provided that this notice
10 * is preserved.
11 * ====================================================
12 *
13 */
14
15 /* tgamma(x)
16 * Gamma function. Returns gamma(x)
17 *
18 * Method: See lgamma_r
19 */
20
21 #include "fdlibm.h"
22
23 #ifdef _NEED_FLOAT64
24
25 __float64
tgamma64(__float64 x)26 tgamma64(__float64 x)
27 {
28 int signgam_local;
29 int divzero = 0;
30
31 if (isless(x, 0.0) && clang_barrier_double(rint(x)) == x)
32 return __math_invalid(x);
33
34 __float64 y = exp64(__math_lgamma_r(x, &signgam_local, &divzero));
35 if (signgam_local < 0)
36 y = -y;
37 if (isinf(y) && finite(x) && !divzero)
38 return __math_oflow(signgam_local < 0);
39 return y;
40 }
41
42 _MATH_ALIAS_d_d(tgamma)
43
44 #endif
45
