e_scalb.c

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

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

#include "math.h"
#include "math_private.h"

#ifdef _SCALB_INT
double
scalb(double x, int fn)
{
    return scalbn(x, fn);
}

#else

double
scalb(double x, double fn)
{
    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