xref: /illumos-gate/usr/src/lib/libm/common/C/atan2pi.c (revision ddc0e0b5)
1*25c28e83SPiotr Jasiukajtis /*
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8*25c28e83SPiotr Jasiukajtis  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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13*25c28e83SPiotr Jasiukajtis  * When distributing Covered Code, include this CDDL HEADER in each
14*25c28e83SPiotr Jasiukajtis  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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21*25c28e83SPiotr Jasiukajtis /*
22*25c28e83SPiotr Jasiukajtis  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
23*25c28e83SPiotr Jasiukajtis  */
24*25c28e83SPiotr Jasiukajtis /*
25*25c28e83SPiotr Jasiukajtis  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
26*25c28e83SPiotr Jasiukajtis  * Use is subject to license terms.
27*25c28e83SPiotr Jasiukajtis  */
28*25c28e83SPiotr Jasiukajtis 
29*25c28e83SPiotr Jasiukajtis /*
30*25c28e83SPiotr Jasiukajtis  * atan2pi(x) = atan2(x)/pi
31*25c28e83SPiotr Jasiukajtis  */
32*25c28e83SPiotr Jasiukajtis 
33*25c28e83SPiotr Jasiukajtis #include "libm.h"
34*25c28e83SPiotr Jasiukajtis 
35*25c28e83SPiotr Jasiukajtis static const double invpi = 0.3183098861837906715377675;
36*25c28e83SPiotr Jasiukajtis 
37*25c28e83SPiotr Jasiukajtis double
atan2pi(double y,double x)38*25c28e83SPiotr Jasiukajtis atan2pi(double y, double x) {
39*25c28e83SPiotr Jasiukajtis 	int	ix, iy;
40*25c28e83SPiotr Jasiukajtis 
41*25c28e83SPiotr Jasiukajtis 	if (x == 0.0 && y == 0.0) {
42*25c28e83SPiotr Jasiukajtis 		ix = ((int *)&x)[HIWORD];
43*25c28e83SPiotr Jasiukajtis 		iy = ((int *)&y)[HIWORD];
44*25c28e83SPiotr Jasiukajtis 		if (ix >= 0)
45*25c28e83SPiotr Jasiukajtis 			return (y);
46*25c28e83SPiotr Jasiukajtis 		return ((iy >= 0)? 1.0 : -1.0);
47*25c28e83SPiotr Jasiukajtis 	}
48*25c28e83SPiotr Jasiukajtis 	return (atan2(y, x) * invpi);
49*25c28e83SPiotr Jasiukajtis }
50