xref: /titanic_44/usr/src/lib/libm/common/complex/cacosh.c (revision 48a4016cae8aa2b8b3d8b258eb22e0c781912bed)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
24  */
25 /*
26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
27  * Use is subject to license terms.
28  */
29 
30 #pragma weak __cacosh = cacosh
31 
32 /* INDENT OFF */
33 /*
34  * dcomplex cacosh(dcomplex z);
35  *	cacosh z = +-i cacos z .
36  * In order to make conj(cacosh(z))=cacosh(conj(z)),
37  * we define
38  *	cacosh z = sign(Im(z))*i cacos z .
39  *
40  */
41 /* INDENT ON */
42 
43 #include "libm.h"	/* fabs/isnan/isinf/signbit */
44 #include "complex_wrapper.h"
45 
46 /* need to work on special cases according to spec */
47 
48 dcomplex
49 cacosh(dcomplex z) {
50 	dcomplex w, ans;
51 	double x, y;
52 
53 	w = cacos(z);
54 	x = D_RE(z);
55 	y = D_IM(z);
56 	if (isnan(y)) {
57 		D_IM(ans) = y + y;
58 		if (isinf(x))
59 			D_RE(ans) = fabs(x);
60 		else
61 			D_RE(ans) = y;
62 	} else if (signbit(y) == 0) {
63 		D_RE(ans) = -D_IM(w);
64 		D_IM(ans) = D_RE(w);
65 	} else {
66 		D_RE(ans) = D_IM(w);
67 		D_IM(ans) = -D_RE(w);
68 	}
69 	return (ans);
70 }
71