kolibrios-gitea/programs/develop/libraries/newlib/math/w_tgamma.c
Sergey Semyonov (Serge) 9ebd703865 newlib: new libm code
git-svn-id: svn://kolibrios.org@3362 a494cfbc-eb01-0410-851d-a64ba20cac60
2013-03-11 18:13:25 +00:00

49 lines
1.1 KiB
C

/* @(#)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 "fdlibm.h"
#ifndef _DOUBLE_IS_32BITS
#ifdef __STDC__
double tgamma(double x)
#else
double tgamma(x)
double x;
#endif
{
double y;
int local_signgam;
y = __ieee754_gamma_r(x,&local_signgam);
if (local_signgam < 0) y = -y;
#ifdef _IEEE_LIBM
return y;
#else
if(_LIB_VERSION == _IEEE_) return y;
if(!finite(y)&&finite(x)) {
if(floor(x)==x&&x<=0.0)
return __kernel_standard(x,x,41); /* tgamma pole */
else
return __kernel_standard(x,x,40); /* tgamma overflow */
}
return y;
#endif
}
#endif /* defined(_DOUBLE_IS_32BITS) */