/* @(#)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>

#include <math-svid-compat.h>

#include <libm-alias-double.h>

#if LIBM_SVID_COMPAT

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;

}

libm_alias_double (__tgamma, tgamma)

#endif