uclibc-ng/libm/w_scalb.c

/*
 * ====================================================
 * 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.
 * ====================================================
 */

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

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

#include <errno.h>

#ifdef _SCALB_INT
double scalb(double x, int fn)		/* wrapper scalb */
#else
double scalb(double x, double fn)	/* wrapper scalb */
#endif
{
#ifdef _IEEE_LIBM
	return __ieee754_scalb(x,fn);
#else
	double z;
	z = __ieee754_scalb(x,fn);
	if(_LIB_VERSION == _IEEE_) return z;
	if(!(isfinite(z)||isnan(z))&&isfinite(x)) {
	    return __kernel_standard(x,(double)fn,32); /* scalb overflow */
	}
	if(z==0.0&&z!=x) {
	    return __kernel_standard(x,(double)fn,33); /* scalb underflow */
	}
#ifndef _SCALB_INT
	if(!isfinite(fn)) errno = ERANGE;
#endif
	return z;
#endif
}