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 /*
36 * sinhl(X)
37 * RETURN THE HYPERBOLIC SINE OF X
38 *
39 * Method :
40 * 1. reduce x to non-negative by sinhl(-x) = - sinhl(x).
41 * 2.
42 *
43 * expm1l(x) + expm1l(x)/(expm1l(x)+1)
44 * 0 <= x <= lnovft : sinhl(x) := --------------------------------
45 * 2
46 *
47 * lnovft <= x < INF : sinhl(x) := expl(x-MEP1*ln2)*2**ME
48 *
49 * here
50 * lnovft: logrithm of the overflow threshold
51 * = MEP1*ln2 chopped to machine precision.
52 * ME maximum exponent
53 * MEP1 maximum exponent plus 1
54 *
55 * Special cases:
56 * sinhl(x) is x if x is +INF, -INF, or NaN.
57 * only sinhl(0)=0 is exact for finite argument.
58 *
59 */
60
61 #define ME 16383
62 #define MEP1 16384
63 #define LNOVFT 1.135652340629414394949193107797076342845e+4L
64 /* last 32 bits of LN2HI is zero */
65 #define LN2HI 6.931471805599453094172319547495844850203e-0001L
66 #define LN2LO 1.667085920830552208890449330400379754169e-0025L
67
68 static const long double
69 half = 0.5L,
70 one = 1.0L,
71 ln2hi = LN2HI,
72 ln2lo = LN2LO,
73 lnovftL = LNOVFT;
74
75 long double
sinhl(long double x)76 sinhl(long double x) {
77 long double r, t;
78
79 if (!finitel(x))
80 return (x + x); /* sinh of NaN or +-INF is itself */
81 r = fabsl(x);
82 if (r < lnovftL) {
83 t = expm1l(r);
84 r = copysignl((t + t / (one + t)) * half, x);
85 } else {
86 r = copysignl(expl((r - MEP1 * ln2hi) - MEP1 * ln2lo), x);
87 r = scalbnl(r, ME);
88 }
89 return (r);
90 }
91