common/C/atan2pi.c

	atan2pi.c revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma weak atan2pi = __atan2pi

/*
 * atan2pi(x) = atan2(x)/pi
 */

#include "libm.h"

static const double invpi = 0.3183098861837906715377675;

double
atan2pi(double y, double x) {
    int ix, iy;

    if (x == 0.0 && y == 0.0) {
        ix = ((int *)&x)[HIWORD];
        iy = ((int *)&y)[HIWORD];
        if (ix >= 0)
            return (y);
        return ((iy >= 0)? 1.0 : -1.0);
    }
    return (atan2(y, x) * invpi);
}