xref: /titanic_41/usr/src/lib/libm/common/complex/ccos.c (revision ae240eb822cbf8b22955d3c6f3facf160df9e04a)
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 __ccos = ccos
31 
32 /* INDENT OFF */
33 /*
34  * dcomplex ccos(dcomplex z);
35  *
36  * z := x+iy; since ccos(iz) = cosh(z), we have
37  * ccos(z)	= ccos((-1)*(-z)) = ccos(i*i*(-z))
38  *		= ccosh(i*(-z)) = ccosh(i*(-x-yi))
39  *		= ccosh(y-ix)
40  */
41 /* INDENT ON */
42 
43 #include "libm.h"
44 #include "complex_wrapper.h"
45 
46 dcomplex
47 ccos(dcomplex z) {
48 	double x, y;
49 
50 	x = D_RE(z);
51 	y = D_IM(z);
52 	D_RE(z) = y;
53 	D_IM(z) = -x;
54 	return (ccosh(z));
55 }
56