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 __sinhl = sinhl
31
32#include "libm.h"
33#include "longdouble.h"
34
35/* SINH(X)
36 * RETURN THE HYPERBOLIC SINE OF X
37 *
38 * Method :
39 *	1. reduce x to non-negative by SINH(-x) = - SINH(x).
40 *	2.
41 *
42 *	                                      EXPM1(x) + EXPM1(x)/(EXPM1(x)+1)
43 *	    0 <= x <= lnovft     : SINH(x) := --------------------------------
44 *			       		                      2
45 *
46 *     lnovft <= x <  INF	 : SINH(x) := EXP(x-MEP1*ln2)*2**ME
47 *
48 * here
49 *	lnovft		logarithm of the overflow threshold
50 *			= MEP1*ln2 chopped to machine precision.
51 *	ME		maximum exponent
52 *	MEP1		maximum exponent plus 1
53 *
54 * Special cases:
55 *	SINH(x) is x if x is +INF, -INF, or NaN.
56 *	only SINH(0)=0 is exact for finite argument.
57 *
58 */
59
60static const long double C[] = {
61	0.5L,
62	1.0L,
63	1.135652340629414394879149e+04L,
64	7.004447686242549087858985e-16L
65};
66
67#define	half	C[0]
68#define	one	C[1]
69#define	lnovft	C[2]
70#define	lnovlo	C[3]
71
72long double
73sinhl(long double x)
74{
75	long double	r, t;
76
77	if (!finitel(x))
78		return (x + x);	/* x is INF or NaN */
79	r = fabsl(x);
80	if (r < lnovft) {
81		t = expm1l(r);
82		r = copysignl((t + t / (one + t)) * half, x);
83	} else {
84		r = copysignl(expl((r - lnovft) - lnovlo), x);
85		r = scalbnl(r, 16383);
86	}
87	return (r);
88}
89