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 __ctanhl = ctanhl
31
32#include "libm.h"	/* expl/expm1l/fabsl/isinfl/isnanl/sincosl/sinl/tanhl */
33#include "complex_wrapper.h"
34#include "longdouble.h"
35
36/* INDENT OFF */
37static const long double four = 4.0L, two = 2.0L, one = 1.0L, zero = 0.0L;
38/* INDENT ON */
39
40ldcomplex
41ctanhl(ldcomplex z) {
42	long double r, u, v, t, x, y, S, C;
43	int hx, ix, hy, iy;
44	ldcomplex ans;
45
46	x = LD_RE(z);
47	y = LD_IM(z);
48	hx = HI_XWORD(x);
49	ix = hx & 0x7fffffff;
50	hy = HI_XWORD(y);
51	iy = hy & 0x7fffffff;
52	x = fabsl(x);
53	y = fabsl(y);
54
55	if (y == zero) {	/* ctanh(x,0) = (x,0) for x = 0 or NaN */
56		LD_RE(ans) = tanhl(x);
57		LD_IM(ans) = zero;
58	} else if (iy >= 0x7fff0000) {	/* y is inf or NaN */
59		if (ix < 0x7fff0000)	/* catanh(finite x,inf/nan) is nan */
60			LD_RE(ans) = LD_IM(ans) = y - y;
61		else if (isinfl(x)) {	/* x is inf */
62			LD_RE(ans) = one;
63			LD_IM(ans) = zero;
64		} else {
65			LD_RE(ans) = x + y;
66			LD_IM(ans) = y - y;
67		}
68	} else if (ix >= 0x4004e000) {
69		/* INDENT OFF */
70		/*
71		 * |x| > 60 = prec/2 (14,28,34,60)
72		 * ctanh z ~ 1 + i (sin2y)/(exp(2x))
73		 */
74		/* INDENT ON */
75		LD_RE(ans) = one;
76		if (iy < 0x7ffe0000)	/* t = sin(2y) */
77			S = sinl(y + y);
78		else {
79			(void) sincosl(y, &S, &C);
80			S = (S + S) * C;
81		}
82		if (ix >= 0x7ffe0000) {	/* |x| > max/2 */
83			if (ix >= 0x7fff0000) {	/* |x| is inf or NaN */
84				if (isnanl(x))	/* x is NaN */
85					LD_RE(ans) = LD_IM(ans) = x + y;
86				else
87					LD_IM(ans) = zero * S;	/* x is inf */
88			} else
89				LD_IM(ans) = S * expl(-x);	/* underflow */
90		} else
91			LD_IM(ans) = (S + S) * expl(-(x + x));
92							/* 2 sin 2y / exp(2x) */
93	} else {
94		/* INDENT OFF */
95		/*
96		 *                        t*t+2t
97		 *    ctanh z = ---------------------------
98		 *               t*t+[4(t+1)(cos y)](cos y)
99		 *
100		 *                  [4(t+1)(cos y)]*(sin y)
101		 *              i --------------------------
102		 *                t*t+[4(t+1)(cos y)](cos y)
103		 */
104		/* INDENT ON */
105		sincosl(y, &S, &C);
106		t = expm1l(x + x);
107		r = (four * C) * (t + one);
108		u = t * t;
109		v = one / (u + r * C);
110		LD_RE(ans) = (u + two * t) * v;
111		LD_IM(ans) = (r * S) * v;
112	}
113	if (hx < 0)
114		LD_RE(ans) = -LD_RE(ans);
115	if (hy < 0)
116		LD_IM(ans) = -LD_IM(ans);
117	return (ans);
118}
119