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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) */