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#include "libm.h"
30
31static const double invpi = 0.3183098861837906715377675;
32
33float
34atan2pif(float y, float x) {
35	int	ix, iy, hx, hy;
36
37	ix = *(int *)&x;
38	iy = *(int *)&y;
39	hx = ix & ~0x80000000;
40	hy = iy & ~0x80000000;
41	if (hx > 0x7f800000 || hy > 0x7f800000) /* x or y is nan */
42		return (x * y);
43	if ((hx | hy) == 0) {
44		/* x and y are both zero */
45		if (ix == 0)
46			return (y);
47		return ((iy == 0)? 1.0f : -1.0f);
48	}
49	return ((float)(invpi * atan2((double)y, (double)x)));
50}
51