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