scalbl.c revision ddc0e0b53c661f6e439e3b7072b3ef353eadb4af
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma weak __scalbl = scalbl
/*
* scalbl(x,n): return x * 2^n by manipulating exponent.
*/
#include "libm.h"
#define n0 0
long double
scalbl(long double x, long double fn) {
int *py = (int *) &fn, n;
long double z;
if (isnanl(x) || isnanl(fn))
return (x * fn);
/*
* fn is inf or NaN
*/
if ((py[n0] & 0x7fff0000) == 0x7fff0000) {
if ((py[n0] & 0x80000000) != 0)
return (x / (-fn));
else
return (x * fn);
}
if (rintl(fn) != fn)
return ((fn - fn) / (fn - fn));
if (fn > 65000.0L)
z = scalbnl(x, 65000);
else if (-fn > 65000.0L)
z = scalbnl(x, -65000);
else {
n = (int) fn;
z = scalbnl(x, n);
}
return (z);
}