1 /* $NetBSD: cacos.c,v 1.1 2007/08/20 16:01:30 drochner Exp $ */
2
3 /*-
4 * Copyright (c) 2007 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software written by Stephen L. Moshier.
8 * It is redistributed by the NetBSD Foundation by permission of the author.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 *
31 * imported and modified include for newlib 2010/10/03
32 * Marco Atzeri <marco_atzeri@yahoo.it>
33 */
34
35 /*
36 FUNCTION
37 <<cacos>>, <<cacosf>>---complex arc cosine
38
39 INDEX
40 cacos
41 INDEX
42 cacosf
43
44 SYNOPSIS
45 #include <complex.h>
46 double complex cacos(double complex <[z]>);
47 float complex cacosf(float complex <[z]>);
48
49
50 DESCRIPTION
51 These functions compute the complex arc cosine of <[z]>,
52 with branch cuts outside the interval [-1, +1] along the real axis.
53
54 <<cacosf>> is identical to <<cacos>>, except that it performs
55 its calculations on <<floats complex>>.
56
57 RETURNS
58 @ifnottex
59 These functions return the complex arc cosine value, in the range
60 of a strip mathematically unbounded along the imaginary axis
61 and in the interval [0, pi] along the real axis.
62 @end ifnottex
63 @tex
64 These functions return the complex arc cosine value, in the range
65 of a strip mathematically unbounded along the imaginary axis
66 and in the interval [<<0>>, $\pi$] along the real axis.
67 @end tex
68
69 PORTABILITY
70 <<cacos>> and <<cacosf>> are ISO C99
71
72 QUICKREF
73 <<cacos>> and <<cacosf>> are ISO C99
74
75 */
76
77 #define _DEFAULT_SOURCE
78 #include <complex.h>
79 #include <math.h>
80
81 double complex
cacos(double complex z)82 cacos(double complex z)
83 {
84 double complex w;
85
86 /* FIXME: The original NetBSD code results in an ICE when trying to
87 build this function on ARM/Thumb using gcc 4.5.1. For now we use
88 a hopefully temporary workaround. */
89 #if 0
90 w = casin(z);
91 w = (M_PI_2 - creal(w)) - cimag(w) * (double complex) (double complex) I;
92 #else
93 double complex tmp0, tmp1;
94
95 tmp0 = casin(z);
96 tmp1 = M_PI_2 - creal(tmp0);
97 w = tmp1 - (cimag(tmp0) * (double complex) (double complex) I);
98 #endif
99 return w;
100 }
101
