OpenBSD-4.6/lib/libm/src/e_scalb.c

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

#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: e_scalb.c,v 1.6 1995/05/10 20:46:09 jtc Exp $";
#endif

/*
 * 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