FreeBSD-5.3/lib/msun/src/w_pow.c

/* @(#)w_pow.c 5.2 93/10/01 */
/*
 * ====================================================
 * 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 pow(x,y) return x**y
 */

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

#ifndef lint
static char rcsid[] = "$FreeBSD: src/lib/msun/src/w_pow.c,v 1.3 2002/05/28 17:51:46 alfred Exp $";
#endif

double
pow(double x, double y)	/* wrapper pow */
{
#ifdef _IEEE_LIBM
	return  __ieee754_pow(x,y);
#else
	double z;
	z=__ieee754_pow(x,y);
	if(_LIB_VERSION == _IEEE_|| isnan(y)) return z;
	if(isnan(x)) {
	    if(y==0.0)
	        return __kernel_standard(x,y,42); /* pow(NaN,0.0) */
	    else
		return z;
	}
	if(x==0.0){
	    if(y==0.0)
	        return __kernel_standard(x,y,20); /* pow(0.0,0.0) */
	    if(finite(y)&&y<0.0)
	        return __kernel_standard(x,y,23); /* pow(0.0,negative) */
	    return z;
	}
	if(!finite(z)) {
	    if(finite(x)&&finite(y)) {
	        if(isnan(z))
	            return __kernel_standard(x,y,24); /* pow neg**non-int */
	        else
	            return __kernel_standard(x,y,21); /* pow overflow */
	    }
	}
	if(z==0.0&&finite(x)&&finite(y))
	    return __kernel_standard(x,y,22); /* pow underflow */
	return z;
#endif
}