1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2011 David Schultz
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice unmodified, this list of conditions, and the following
12 *    disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/*
30 * Hyperbolic tangent of a complex argument z.  See s_ctanh.c for details.
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD$");
35
36#include <complex.h>
37#include <math.h>
38
39#include "math_private.h"
40
41float complex
42ctanhf(float complex z)
43{
44	volatile float x, y;
45	float t, beta, s, rho, denom;
46	uint32_t hx, ix;
47
48	x = crealf(z);
49	y = cimagf(z);
50
51	GET_FLOAT_WORD(hx, x);
52	ix = hx & 0x7fffffff;
53
54	if (ix >= 0x7f800000) {
55		if (ix & 0x7fffff)
56			return (CMPLXF(nan_mix(x, y),
57			    y == 0 ? y : nan_mix(x, y)));
58		SET_FLOAT_WORD(x, hx - 0x40000000);
59		return (CMPLXF(x,
60		    copysignf(0, isinf(y) ? y : sinf(y) * cosf(y))));
61	}
62
63	if (!isfinite(y))
64		return (CMPLXF(ix ? y - y : x, y - y));
65
66	if (ix >= 0x41300000) {	/* |x| >= 11 */
67		float exp_mx = expf(-fabsf(x));
68		return (CMPLXF(copysignf(1, x),
69		    4 * sinf(y) * cosf(y) * exp_mx * exp_mx));
70	}
71
72	t = tanf(y);
73	beta = 1.0 + t * t;
74	s = sinhf(x);
75	rho = sqrtf(1 + s * s);
76	denom = 1 + beta * s * s;
77	return (CMPLXF((beta * rho * s) / denom, t / denom));
78}
79
80float complex
81ctanf(float complex z)
82{
83
84	z = ctanhf(CMPLXF(cimagf(z), crealf(z)));
85	return (CMPLXF(cimagf(z), crealf(z)));
86}
87
88