/*
* 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 __acoshl = acoshl
#include "libm.h"
static const long double
zero = 0.0L,
ln2 = 6.931471805599453094172321214581765680755e-0001L,
one = 1.0L,
big = 1.e+20L;
long double
acoshl(long double x) {
long double t;
if (isnanl(x))
return (x + x);
else if (x > big)
return (logl(x) + ln2);
else if (x > one) {
t = sqrtl(x - one);
return (log1pl(t * (t + sqrtl(x + one))));
} else if (x == one)
return (zero);
else
return ((x - x) / (x - x));
}