xref: /titanic_51/usr/src/lib/libm/common/R/atan2pif.c (revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8)
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  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
23  */
24 /*
25  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
26  * Use is subject to license terms.
27  */
28 
29 #pragma weak atan2pif = __atan2pif
30 
31 #include "libm.h"
32 
33 static const double invpi = 0.3183098861837906715377675;
34 
35 float
36 atan2pif(float y, float x) {
37 	int	ix, iy, hx, hy;
38 
39 	ix = *(int *)&x;
40 	iy = *(int *)&y;
41 	hx = ix & ~0x80000000;
42 	hy = iy & ~0x80000000;
43 	if (hx > 0x7f800000 || hy > 0x7f800000) /* x or y is nan */
44 		return (x * y);
45 	if ((hx | hy) == 0) {
46 		/* x and y are both zero */
47 		if (ix == 0)
48 			return (y);
49 		return ((iy == 0)? 1.0f : -1.0f);
50 	}
51 	return ((float)(invpi * atan2((double)y, (double)x)));
52 }
53