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 */
36static const float four = 4.0F, two = 2.0F, one = 1.0F, zero = 0.0F;
37/* INDENT ON */
38
39fcomplex
40ctanhf(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}
116