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--- old/usr/src/lib/libm/common/LD/tanhl.c
+++ new/usr/src/lib/libm/common/LD/tanhl.c
1 1 /*
2 2 * CDDL HEADER START
3 3 *
4 4 * The contents of this file are subject to the terms of the
5 5 * Common Development and Distribution License (the "License").
6 6 * You may not use this file except in compliance with the License.
7 7 *
8 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 9 * or http://www.opensolaris.org/os/licensing.
10 10 * See the License for the specific language governing permissions
11 11 * and limitations under the License.
12 12 *
13 13 * When distributing Covered Code, include this CDDL HEADER in each
14 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 15 * If applicable, add the following below this CDDL HEADER, with the
16 16 * fields enclosed by brackets "[]" replaced with your own identifying
17 17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 18 *
19 19 * CDDL HEADER END
20 20 */
21 21
22 22 /*
23 23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 24 */
25 25 /*
26 26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
27 27 * Use is subject to license terms.
28 28 */
29 29
30 30 #if defined(ELFOBJ)
31 31 #pragma weak tanhl = __tanhl
32 32 #endif
33 33
34 34 /*
35 35 * tanhl(x) returns the hyperbolic tangent of x
36 36 *
37 37 * Method :
38 38 * 1. reduce x to non-negative: tanhl(-x) = - tanhl(x).
39 39 * 2.
40 40 * 0 < x <= small : tanhl(x) := x
41 41 * -expm1l(-2x)
42 42 * small < x <= 1 : tanhl(x) := --------------
43 43 * expm1l(-2x) + 2
44 44 * 2
45 45 * 1 <= x <= threshold : tanhl(x) := 1 - ---------------
46 46 * expm1l(2x) + 2
47 47 * threshold < x <= INF : tanhl(x) := 1.
48 48 *
49 49 * where
50 50 * single : small = 1.e-5 threshold = 11.0
51 51 * double : small = 1.e-10 threshold = 22.0
52 52 * quad : small = 1.e-20 threshold = 45.0
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53 53 *
54 54 * Note: threshold was chosen so that
55 55 * fl(1.0+2/(expm1(2*threshold)+2)) == 1.
56 56 *
57 57 * Special cases:
58 58 * tanhl(NaN) is NaN;
59 59 * only tanhl(0.0)=0.0 is exact for finite argument.
60 60 */
61 61
62 62 #include "libm.h"
63 +#include "longdouble.h"
63 64
64 65 static const long double small = 1.0e-20L, one = 1.0, two = 2.0,
65 66 #ifndef lint
66 67 big = 1.0e+20L,
67 68 #endif
68 69 threshold = 45.0L;
69 70
70 71 long double
71 72 tanhl(long double x) {
72 73 long double t, y, z;
73 74 int signx;
75 + volatile long double dummy;
74 76
75 77 if (isnanl(x))
76 78 return (x + x); /* x is NaN */
77 79 signx = signbitl(x);
78 80 t = fabsl(x);
79 81 z = one;
80 82 if (t <= threshold) {
81 83 if (t > one)
82 84 z = one - two / (expm1l(t + t) + two);
83 85 else if (t > small) {
84 86 y = expm1l(-t - t);
85 87 z = -y / (y + two);
86 88 } else {
87 89 #ifndef lint
88 - volatile long double dummy = t + big;
90 + dummy = t + big;
89 91 /* inexact if t != 0 */
90 92 #endif
91 93 return (x);
92 94 }
93 95 } else if (!finitel(t))
94 96 return (copysignl(one, x));
95 97 else
96 98 return (signx ? -z + small * small : z - small * small);
97 99 return (signx ? -z : z);
98 100 }
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