xref: /titanic_41/usr/src/lib/libm/common/C/atan2pi.c (revision a9d3dcd5820128b4f34bf38f447e47aa95c004e8)
1*5b2ba9d3SPiotr Jasiukajtis /*
2*5b2ba9d3SPiotr Jasiukajtis  * CDDL HEADER START
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7*5b2ba9d3SPiotr Jasiukajtis  *
8*5b2ba9d3SPiotr Jasiukajtis  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9*5b2ba9d3SPiotr Jasiukajtis  * or http://www.opensolaris.org/os/licensing.
10*5b2ba9d3SPiotr Jasiukajtis  * See the License for the specific language governing permissions
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12*5b2ba9d3SPiotr Jasiukajtis  *
13*5b2ba9d3SPiotr Jasiukajtis  * When distributing Covered Code, include this CDDL HEADER in each
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15*5b2ba9d3SPiotr Jasiukajtis  * If applicable, add the following below this CDDL HEADER, with the
16*5b2ba9d3SPiotr Jasiukajtis  * fields enclosed by brackets "[]" replaced with your own identifying
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19*5b2ba9d3SPiotr Jasiukajtis  * CDDL HEADER END
20*5b2ba9d3SPiotr Jasiukajtis  */
21*5b2ba9d3SPiotr Jasiukajtis /*
22*5b2ba9d3SPiotr Jasiukajtis  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
23*5b2ba9d3SPiotr Jasiukajtis  */
24*5b2ba9d3SPiotr Jasiukajtis /*
25*5b2ba9d3SPiotr Jasiukajtis  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
26*5b2ba9d3SPiotr Jasiukajtis  * Use is subject to license terms.
27*5b2ba9d3SPiotr Jasiukajtis  */
28*5b2ba9d3SPiotr Jasiukajtis 
29*5b2ba9d3SPiotr Jasiukajtis /*
30*5b2ba9d3SPiotr Jasiukajtis  * atan2pi(x) = atan2(x)/pi
31*5b2ba9d3SPiotr Jasiukajtis  */
32*5b2ba9d3SPiotr Jasiukajtis 
33*5b2ba9d3SPiotr Jasiukajtis #include "libm.h"
34*5b2ba9d3SPiotr Jasiukajtis 
35*5b2ba9d3SPiotr Jasiukajtis static const double invpi = 0.3183098861837906715377675;
36*5b2ba9d3SPiotr Jasiukajtis 
37*5b2ba9d3SPiotr Jasiukajtis double
atan2pi(double y,double x)38*5b2ba9d3SPiotr Jasiukajtis atan2pi(double y, double x) {
39*5b2ba9d3SPiotr Jasiukajtis 	int	ix, iy;
40*5b2ba9d3SPiotr Jasiukajtis 
41*5b2ba9d3SPiotr Jasiukajtis 	if (x == 0.0 && y == 0.0) {
42*5b2ba9d3SPiotr Jasiukajtis 		ix = ((int *)&x)[HIWORD];
43*5b2ba9d3SPiotr Jasiukajtis 		iy = ((int *)&y)[HIWORD];
44*5b2ba9d3SPiotr Jasiukajtis 		if (ix >= 0)
45*5b2ba9d3SPiotr Jasiukajtis 			return (y);
46*5b2ba9d3SPiotr Jasiukajtis 		return ((iy >= 0)? 1.0 : -1.0);
47*5b2ba9d3SPiotr Jasiukajtis 	}
48*5b2ba9d3SPiotr Jasiukajtis 	return (atan2(y, x) * invpi);
49*5b2ba9d3SPiotr Jasiukajtis }
50