e_scalb.c

/*
 *                               POK header
 * 
 * The following file is a part of the POK project. Any modification should
 * made according to the POK licence. You CANNOT use this file or a part of
 * this file is this part of a file for your own project
 *
 * For more information on the POK licence, please see our LICENCE FILE
 *
 * Please follow the coding guidelines described in doc/CODING_GUIDELINES
 *
 *                                      Copyright (c) 2007-2009 POK team 
 *
 * Created by julien on Fri Jan 30 14:41:34 2009 
 */

/* @(#)e_scalb.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.
 * ====================================================
 */

/*
 * __ieee754_scalb(x, fn) is provide for
 * passing various standard test suite. One
 * should use scalbn() instead.
 */

#ifdef POK_NEEDS_LIBMATH

#include <libm.h>
#include "math_private.h"

#ifdef _SCALB_INT
double
__ieee754_scalb(double x, int fn)
#else
double
__ieee754_scalb(double x, double fn)
#endif
{
#ifdef _SCALB_INT
        return scalbn(x,fn);
#else
        if (isnan(x)||isnan(fn)) return x*fn;
        if (!finite(fn)) {
            if(fn>0.0) return x*fn;
            else       return x/(-fn);
        }
        if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
        if ( fn > 65000.0) return scalbn(x, 65000);
        if (-fn > 65000.0) return scalbn(x,-65000);
        return scalbn(x,(int)fn);
#endif
}
#endif