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 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
23 */
24 /*
25 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
26 * Use is subject to license terms.
27 */
28
29 #pragma weak __sinh = sinh
30
31 /* INDENT OFF */
32 /*
33 * sinh(x)
34 * Code originated from 4.3bsd.
35 * Modified by K.C. Ng for SUN 4.0 libm.
36 * Method :
37 * 1. reduce x to non-negative by sinh(-x) = - sinh(x).
38 * 2.
39 *
40 * expm1(x) + expm1(x)/(expm1(x)+1)
41 * 0 <= x <= lnovft : sinh(x) := --------------------------------
42 * 2
43 * lnovft <= x < INF : sinh(x) := exp(x-1024*ln2)*2**1023
44 *
45 *
46 * Special cases:
47 * sinh(x) is x if x is +INF, -INF, or NaN.
48 * only sinh(0)=0 is exact for finite argument.
49 *
50 */
51 /* INDENT ON */
52
53 #include "libm.h"
54
55 static const double
56 ln2hi = 6.93147180369123816490e-01,
57 ln2lo = 1.90821492927058770002e-10,
58 lnovft = 7.09782712893383973096e+02;
59
60 double
sinh(double x)61 sinh(double x) {
62 double ox, r, t;
63
64 ox = x;
65 r = fabs(x);
66 if (!finite(x))
67 return (x * r);
68 if (r < lnovft) {
69 t = expm1(r);
70 r = copysign((t + t / (1.0 + t)) * 0.5, x);
71 } else {
72 if (r < 1000.0)
73 x = copysign(exp((r - 1024 * ln2hi) - 1024 * ln2lo), x);
74 r = scalbn(x, 1023);
75 }
76 if (!finite(r))
77 r = _SVID_libm_err(ox, ox, 25);
78 return (r);
79 }
80