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/* @(#)w_lgamma.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 lgamma(double x)
* Return the logarithm of the Gamma function of x.
*
* Method: call __ieee754_lgamma_r
*/
#include "fdlibm.h"
#include <reent.h>
#include <errno.h>
#ifndef _DOUBLE_IS_32BITS
#ifdef __STDC__
double lgamma(double x)
#else
double lgamma(x)
double x;
#endif
{
#ifdef _IEEE_LIBM
return __ieee754_lgamma_r(x,&(_REENT_SIGNGAM(_REENT)));
#else
double y;
struct exception exc;
y = __ieee754_lgamma_r(x,&(_REENT_SIGNGAM(_REENT)));
if(_LIB_VERSION == _IEEE_) return y;
if(!finite(y)&&finite(x)) {
#ifndef HUGE_VAL
#define HUGE_VAL inf
double inf = 0.0;
SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */
#endif
exc.name = "lgamma";
exc.err = 0;
exc.arg1 = x;
exc.arg2 = x;
if (_LIB_VERSION == _SVID_)
exc.retval = HUGE;
else
exc.retval = HUGE_VAL;
if(floor(x)==x&&x<=0.0) {
/* lgamma(-integer) */
exc.type = SING;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
errno = EDOM;
}
} else {
/* lgamma(finite) overflow */
exc.type = OVERFLOW;
if (_LIB_VERSION == _POSIX_)
errno = ERANGE;
else if (!matherr(&exc)) {
errno = ERANGE;
}
}
if (exc.err != 0)
errno = exc.err;
return exc.retval;
} else
return y;
#endif
}
#endif /* defined(_DOUBLE_IS_32BITS) */
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