1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2005 Bruce D. Evans and Steven G. Kargl
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 sine of a complex argument z = x + i y.
31 *
32 * sinh(z) = sinh(x+iy)
33 *         = sinh(x) cos(y) + i cosh(x) sin(y).
34 *
35 * Exceptional values are noted in the comments within the source code.
36 * These values and the return value were taken from n1124.pdf.
37 * The sign of the result for some exceptional values is unspecified but
38 * must satisfy both sinh(conj(z)) == conj(sinh(z)) and sinh(-z) == -sinh(z).
39 */
40
41#include <complex.h>
42#include <math.h>
43
44#include "math_private.h"
45
46static const double huge = 0x1p1023;
47
48double complex
49csinh(double complex z)
50{
51	double x, y, h;
52	int32_t hx, hy, ix, iy, lx, ly;
53
54	x = creal(z);
55	y = cimag(z);
56
57	EXTRACT_WORDS(hx, lx, x);
58	EXTRACT_WORDS(hy, ly, y);
59
60	ix = 0x7fffffff & hx;
61	iy = 0x7fffffff & hy;
62
63	/* Handle the nearly-non-exceptional cases where x and y are finite. */
64	if (ix < 0x7ff00000 && iy < 0x7ff00000) {
65		if ((iy | ly) == 0)
66			return (CMPLX(sinh(x), y));
67		if (ix < 0x40360000)	/* |x| < 22: normal case */
68			return (CMPLX(sinh(x) * cos(y), cosh(x) * sin(y)));
69
70		/* |x| >= 22, so cosh(x) ~= exp(|x|) */
71		if (ix < 0x40862e42) {
72			/* x < 710: exp(|x|) won't overflow */
73			h = exp(fabs(x)) * 0.5;
74			return (CMPLX(copysign(h, x) * cos(y), h * sin(y)));
75		} else if (ix < 0x4096bbaa) {
76			/* x < 1455: scale to avoid overflow */
77			z = __ldexp_cexp(CMPLX(fabs(x), y), -1);
78			return (CMPLX(creal(z) * copysign(1, x), cimag(z)));
79		} else {
80			/* x >= 1455: the result always overflows */
81			h = huge * x;
82			return (CMPLX(h * cos(y), h * h * sin(y)));
83		}
84	}
85
86	/*
87	 * sinh(+-0 +- I Inf) = +-0 + I dNaN.
88	 * The sign of 0 in the result is unspecified.  Choice = same sign
89	 * as the argument.  Raise the invalid floating-point exception.
90	 *
91	 * sinh(+-0 +- I NaN) = +-0 + I d(NaN).
92	 * The sign of 0 in the result is unspecified.  Choice = same sign
93	 * as the argument.
94	 */
95	if ((ix | lx) == 0)		/* && iy >= 0x7ff00000 */
96		return (CMPLX(x, y - y));
97
98	/*
99	 * sinh(+-Inf +- I 0) = +-Inf + I +-0.
100	 *
101	 * sinh(NaN +- I 0)   = d(NaN) + I +-0.
102	 */
103	if ((iy | ly) == 0)		/* && ix >= 0x7ff00000 */
104		return (CMPLX(x + x, y));
105
106	/*
107	 * sinh(x +- I Inf) = dNaN + I dNaN.
108	 * Raise the invalid floating-point exception for finite nonzero x.
109	 *
110	 * sinh(x + I NaN) = d(NaN) + I d(NaN).
111	 * Optionally raises the invalid floating-point exception for finite
112	 * nonzero x.  Choice = don't raise (except for signaling NaNs).
113	 */
114	if (ix < 0x7ff00000)		/* && iy >= 0x7ff00000 */
115		return (CMPLX(y - y, y - y));
116
117	/*
118	 * sinh(+-Inf + I NaN)  = +-Inf + I d(NaN).
119	 * The sign of Inf in the result is unspecified.  Choice = same sign
120	 * as the argument.
121	 *
122	 * sinh(+-Inf +- I Inf) = +-Inf + I dNaN.
123	 * The sign of Inf in the result is unspecified.  Choice = same sign
124	 * as the argument.  Raise the invalid floating-point exception.
125	 *
126	 * sinh(+-Inf + I y)   = +-Inf cos(y) + I Inf sin(y)
127	 */
128	if (ix == 0x7ff00000 && lx == 0) {
129		if (iy >= 0x7ff00000)
130			return (CMPLX(x, y - y));
131		return (CMPLX(x * cos(y), INFINITY * sin(y)));
132	}
133
134	/*
135	 * sinh(NaN1 + I NaN2) = d(NaN1, NaN2) + I d(NaN1, NaN2).
136	 *
137	 * sinh(NaN +- I Inf)  = d(NaN, dNaN) + I d(NaN, dNaN).
138	 * Optionally raises the invalid floating-point exception.
139	 * Choice = raise.
140	 *
141	 * sinh(NaN + I y)     = d(NaN) + I d(NaN).
142	 * Optionally raises the invalid floating-point exception for finite
143	 * nonzero y.  Choice = don't raise (except for signaling NaNs).
144	 */
145	return (CMPLX(((long double)x + x) * (y - y),
146	    ((long double)x * x) * (y - y)));
147}
148
149double complex
150csin(double complex z)
151{
152
153	/* csin(z) = -I * csinh(I * z) = I * conj(csinh(I * conj(z))). */
154	z = csinh(CMPLX(cimag(z), creal(z)));
155	return (CMPLX(cimag(z), creal(z)));
156}
157