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 ctanhf = __ctanhf
31
32 #include "libm.h" /* expf/expm1f/fabsf/sincosf/sinf/tanhf */
33 #include "complex_wrapper.h"
34
35 /* INDENT OFF */
36 static const float four = 4.0F, two = 2.0F, one = 1.0F, zero = 0.0F;
37 /* INDENT ON */
38
39 fcomplex
40 ctanhf(fcomplex z) {
41 float r, u, v, t, x, y, S, C;
42 int hx, ix, hy, iy;
43 fcomplex ans;
44
45 x = F_RE(z);
46 y = F_IM(z);
47 hx = THE_WORD(x);
48 ix = hx & 0x7fffffff;
49 hy = THE_WORD(y);
50 iy = hy & 0x7fffffff;
51 x = fabsf(x);
52 y = fabsf(y);
53
54 if (iy == 0) { /* ctanh(x,0) = (x,0) for x = 0 or NaN */
55 F_RE(ans) = tanhf(x);
56 F_IM(ans) = zero;
57 } else if (iy >= 0x7f800000) { /* y is inf or NaN */
58 if (ix < 0x7f800000) /* catanh(finite x,inf/nan) is nan */
59 F_RE(ans) = F_IM(ans) = y - y;
60 else if (ix == 0x7f800000) { /* x is inf */
61 F_RE(ans) = one;
62 F_IM(ans) = zero;
63 } else {
64 F_RE(ans) = x + y;
65 F_IM(ans) = y - y;
66 }
67 } else if (ix >= 0x41600000) {
68 /*
69 * |x| > 14 = prec/2 (14,28,34,60)
70 * ctanh z ~ 1 + i (sin2y)/(exp(2x))
71 */
72 F_RE(ans) = one;
73 if (iy < 0x7f000000) /* t = sin(2y) */
74 S = sinf(y + y);
75 else {
76 (void) sincosf(y, &S, &C);
77 S = (S + S) * C;
78 }
79 if (ix >= 0x7f000000) { /* |x| > max/2 */
80 if (ix >= 0x7f800000) { /* |x| is inf or NaN */
81 if (ix > 0x7f800000) /* x is NaN */
82 F_RE(ans) = F_IM(ans) = x + y;
83 else
84 F_IM(ans) = zero * S; /* x is inf */
85 } else
86 F_IM(ans) = S * expf(-x); /* underflow */
87 } else
88 F_IM(ans) = (S + S) * expf(-(x + x));
89 /* 2 sin 2y / exp(2x) */
90 } else {
91 /* INDENT OFF */
92 /*
93 * t*t+2t
94 * ctanh z = ---------------------------
95 * t*t+[4(t+1)(cos y)](cos y)
96 *
97 * [4(t+1)(cos y)]*(sin y)
98 * i --------------------------
99 * t*t+[4(t+1)(cos y)](cos y)
100 */
101 /* INDENT ON */
102 (void) sincosf(y, &S, &C);
103 t = expm1f(x + x);
104 r = (four * C) * (t + one);
105 u = t * t;
106 v = one / (u + r * C);
107 F_RE(ans) = (u + two * t) * v;
108 F_IM(ans) = (r * S) * v;
109 }
110 if (hx < 0)
111 F_RE(ans) = -F_RE(ans);
112 if (hy < 0)
113 F_IM(ans) = -F_IM(ans);
114 return (ans);
115 }