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/*
30 * atan2pi(x) = atan2(x)/pi
31 */
32
33#include "libm.h"
34
35static const double invpi = 0.3183098861837906715377675;
36
37double
38atan2pi(double y, double x) {
39	int	ix, iy;
40
41	if (x == 0.0 && y == 0.0) {
42		ix = ((int *)&x)[HIWORD];
43		iy = ((int *)&y)[HIWORD];
44		if (ix >= 0)
45			return (y);
46		return ((iy >= 0)? 1.0 : -1.0);
47	}
48	return (atan2(y, x) * invpi);
49}
50