sinh.c revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8
/*
* 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 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma weak sinh = __sinh
/* INDENT OFF */
/*
* sinh(x)
* Code originated from 4.3bsd.
* Modified by K.C. Ng for SUN 4.0 libm.
* Method :
* 1. reduce x to non-negative by sinh(-x) = - sinh(x).
* 2.
*
* expm1(x) + expm1(x)/(expm1(x)+1)
* 0 <= x <= lnovft : sinh(x) := --------------------------------
* 2
* lnovft <= x < INF : sinh(x) := exp(x-1024*ln2)*2**1023
*
*
* Special cases:
* sinh(x) is x if x is +INF, -INF, or NaN.
* only sinh(0)=0 is exact for finite argument.
*
*/
/* INDENT ON */
#include "libm.h"
static const double
ln2hi = 6.93147180369123816490e-01,
ln2lo = 1.90821492927058770002e-10,
lnovft = 7.09782712893383973096e+02;
double
sinh(double x) {
double ox, r, t;
ox = x;
r = fabs(x);
if (!finite(x))
return (x * r);
if (r < lnovft) {
t = expm1(r);
r = copysign((t + t / (1.0 + t)) * 0.5, x);
} else {
if (r < 1000.0)
x = copysign(exp((r - 1024 * ln2hi) - 1024 * ln2lo), x);
r = scalbn(x, 1023);
}
if (!finite(r))
r = _SVID_libm_err(ox, ox, 25);
return (r);
}