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 /*
  23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  24  */
  25 
  26 /*
  27  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
  28  * Use is subject to license terms.
  29  */
  30 
  31 #pragma weak __carg = carg
  32 
  33 #include <math.h>                 /* atan2 */
  34 #include "complex_wrapper.h"
  35 
  36 static const double pi = 3.14159265358979311600e+00,
  37         pi_lo = 1.22464679914735320717e-16;
  38 
  39 double
  40 carg(dcomplex z)
  41 {
  42         int ix, iy;
  43 
  44         ix = ((int *)&(D_RE(z)))[HIWORD];
  45         iy = ((int *)&(D_IM(z)))[HIWORD];
  46 
  47         if ((((ix | iy) & ~0x80000000) | ((int *)&(D_RE(z)))[LOWORD] |
  48             ((int *)&(D_IM(z)))[LOWORD]) == 0) {
  49                 /* x and y are both zero */
  50                 if (ix == 0)
  51                         return (D_IM(z));
  52 
  53                 return ((iy == 0) ? pi + pi_lo : -pi - pi_lo);
  54         }
  55 
  56         return (atan2(D_IM(z), D_RE(z)));
  57 }