1 /* $NetBSD: catanf.c,v 1.1 2007/08/20 16:01:32 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 #include <complex.h>
36 #include <math.h>
37 #include "cephes_subrf.h"
38
39 #ifdef __weak_alias
__weak_alias(catanf,_catanf)40 __weak_alias(catanf, _catanf)
41 #endif
42
43 float complex
44 catanf(float complex z)
45 {
46 float complex w;
47 float a, t, x, x2, y;
48
49 x = crealf(z);
50 y = cimagf(z);
51
52 if ((x == 0.0f) && (y > 1.0f))
53 goto ovrf;
54
55 x2 = x * x;
56 a = 1.0f - x2 - (y * y);
57
58 t = 0.5f * atan2f(2.0f * x, a);
59 w = _redupif(t);
60
61 t = y - 1.0f;
62 a = x2 + (t * t);
63 if (a == 0.0f)
64 goto ovrf;
65
66 t = y + 1.0f;
67 a = (x2 + (t * t))/a;
68 w = w + (0.25f * logf(a)) * I;
69 return w;
70
71 ovrf:
72 #if 0
73 mtherr ("catan", OVERFLOW);
74 #endif
75 w = HUGE_VALF + HUGE_VALF * I;
76 return w;
77 }
78
