xref: /freebsd/lib/msun/src/s_csinhf.c (revision b1f92fa22938fe29ab7e53692ffe0ed7a0ecc4d0)
1 /*-
2  * Copyright (c) 2005 Bruce D. Evans and Steven G. Kargl
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice unmodified, this list of conditions, and the following
10  *    disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 /*
28  * Float version of csinh().  See s_csinh.c for details.
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <complex.h>
35 #include <math.h>
36 
37 #include "math_private.h"
38 
39 static const float huge = 0x1p127;
40 
41 float complex
42 csinhf(float complex z)
43 {
44 	float x, y, h;
45 	int32_t hx, hy, ix, iy;
46 
47 	x = crealf(z);
48 	y = cimagf(z);
49 
50 	GET_FLOAT_WORD(hx, x);
51 	GET_FLOAT_WORD(hy, y);
52 
53 	ix = 0x7fffffff & hx;
54 	iy = 0x7fffffff & hy;
55 
56 	if (ix < 0x7f800000 && iy < 0x7f800000) {
57 		if (iy == 0)
58 			return (CMPLXF(sinhf(x), y));
59 		if (ix < 0x41100000)	/* |x| < 9: normal case */
60 			return (CMPLXF(sinhf(x) * cosf(y), coshf(x) * sinf(y)));
61 
62 		/* |x| >= 9, so cosh(x) ~= exp(|x|) */
63 		if (ix < 0x42b17218) {
64 			/* x < 88.7: expf(|x|) won't overflow */
65 			h = expf(fabsf(x)) * 0.5F;
66 			return (CMPLXF(copysignf(h, x) * cosf(y), h * sinf(y)));
67 		} else if (ix < 0x4340b1e7) {
68 			/* x < 192.7: scale to avoid overflow */
69 			z = __ldexp_cexpf(CMPLXF(fabsf(x), y), -1);
70 			return (CMPLXF(crealf(z) * copysignf(1, x), cimagf(z)));
71 		} else {
72 			/* x >= 192.7: the result always overflows */
73 			h = huge * x;
74 			return (CMPLXF(h * cosf(y), h * h * sinf(y)));
75 		}
76 	}
77 
78 	if (ix == 0)			/* && iy >= 0x7f800000 */
79 		return (CMPLXF(x, y - y));
80 
81 	if (iy == 0)			/* && ix >= 0x7f800000 */
82 		return (CMPLXF(x + x, y));
83 
84 	if (ix < 0x7f800000)		/* && iy >= 0x7f800000 */
85 		return (CMPLXF(y - y, y - y));
86 
87 	if (ix == 0x7f800000) {
88 		if (iy >= 0x7f800000)
89 			return (CMPLXF(x, y - y));
90 		return (CMPLXF(x * cosf(y), INFINITY * sinf(y)));
91 	}
92 
93 	return (CMPLXF((x + x) * (y - y), (x * x) * (y - y)));
94 }
95 
96 float complex
97 csinf(float complex z)
98 {
99 
100 	z = csinhf(CMPLXF(cimagf(z), crealf(z)));
101 	return (CMPLXF(cimagf(z), crealf(z)));
102 }
103