xref: /illumos-gate/usr/src/lib/libm/common/LD/asinhl.c (revision 8119dad84d6416f13557b0ba8e2aaf9064cbcfd3)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
24  */
25 /*
26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
27  * Use is subject to license terms.
28  */
29 
30 #pragma weak __asinhl = asinhl
31 
32 #include "libm.h"
33 
34 static const long double
35 	ln2	= 6.931471805599453094172321214581765680755e-0001L,
36 	one	= 1.0L,
37 	big	= 1.0e+20L,
38 	tiny	= 1.0e-20L;
39 
40 long double
41 asinhl(long double x) {
42 	long double t, w;
43 #ifndef lint
44 	volatile long double dummy __unused;
45 #endif
46 
47 	w = fabsl(x);
48 	if (isnanl(x))
49 		return (x + x);	/* x is NaN */
50 	if (w < tiny) {
51 #ifndef lint
52 		dummy = x + big;	/* inexact if x != 0 */
53 #endif
54 		return (x);	/* tiny x */
55 	} else if (w < big) {
56 		t = one / w;
57 		return (copysignl(log1pl(w + w / (t + sqrtl(one + t * t))), x));
58 	} else
59 		return (copysignl(logl(w) + ln2, x));
60 }
61