xref: /aosp_15_r20/external/fdlibm/w_lgamma.c (revision 1e651e1ef2b613db2c4b29ae59c1de74cf0222ae)
1*1e651e1eSRoland Levillain 
2*1e651e1eSRoland Levillain /* @(#)w_lgamma.c 1.3 95/01/18 */
3*1e651e1eSRoland Levillain /*
4*1e651e1eSRoland Levillain  * ====================================================
5*1e651e1eSRoland Levillain  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6*1e651e1eSRoland Levillain  *
7*1e651e1eSRoland Levillain  * Developed at SunSoft, a Sun Microsystems, Inc. business.
8*1e651e1eSRoland Levillain  * Permission to use, copy, modify, and distribute this
9*1e651e1eSRoland Levillain  * software is freely granted, provided that this notice
10*1e651e1eSRoland Levillain  * is preserved.
11*1e651e1eSRoland Levillain  * ====================================================
12*1e651e1eSRoland Levillain  *
13*1e651e1eSRoland Levillain  */
14*1e651e1eSRoland Levillain 
15*1e651e1eSRoland Levillain /* double ieee_lgamma(double x)
16*1e651e1eSRoland Levillain  * Return the logarithm of the Gamma function of x.
17*1e651e1eSRoland Levillain  *
18*1e651e1eSRoland Levillain  * Method: call __ieee754_lgamma_r
19*1e651e1eSRoland Levillain  */
20*1e651e1eSRoland Levillain 
21*1e651e1eSRoland Levillain #include "fdlibm.h"
22*1e651e1eSRoland Levillain 
23*1e651e1eSRoland Levillain extern int signgam;
24*1e651e1eSRoland Levillain 
25*1e651e1eSRoland Levillain #ifdef __STDC__
ieee_lgamma(double x)26*1e651e1eSRoland Levillain 	double ieee_lgamma(double x)
27*1e651e1eSRoland Levillain #else
28*1e651e1eSRoland Levillain 	double ieee_lgamma(x)
29*1e651e1eSRoland Levillain 	double x;
30*1e651e1eSRoland Levillain #endif
31*1e651e1eSRoland Levillain {
32*1e651e1eSRoland Levillain #ifdef _IEEE_LIBM
33*1e651e1eSRoland Levillain 	return __ieee754_lgamma_r(x,&signgam);
34*1e651e1eSRoland Levillain #else
35*1e651e1eSRoland Levillain         double y;
36*1e651e1eSRoland Levillain         y = __ieee754_lgamma_r(x,&signgam);
37*1e651e1eSRoland Levillain         if(_LIB_VERSION == _IEEE_) return y;
38*1e651e1eSRoland Levillain         if(!ieee_finite(y)&&ieee_finite(x)) {
39*1e651e1eSRoland Levillain             if(ieee_floor(x)==x&&x<=0.0)
40*1e651e1eSRoland Levillain                 return __kernel_standard(x,x,15); /* lgamma pole */
41*1e651e1eSRoland Levillain             else
42*1e651e1eSRoland Levillain                 return __kernel_standard(x,x,14); /* lgamma overflow */
43*1e651e1eSRoland Levillain         } else
44*1e651e1eSRoland Levillain             return y;
45*1e651e1eSRoland Levillain #endif
46*1e651e1eSRoland Levillain }
47