usr/src/lib/libm/common/complex/ccos.c

   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  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  27  * Use is subject to license terms.
  28  */
  29
  30 #pragma weak __ccos = ccos
  31
  32 /* INDENT OFF */
  33 /*
  34  * dcomplex ccos(dcomplex z);
  35  *
  36  * z := x+iy; since ccos(iz) = cosh(z), we have
  37  * ccos(z)      = ccos((-1)*(-z)) = ccos(i*i*(-z))
  38  *              = ccosh(i*(-z)) = ccosh(i*(-x-yi))
  39  *              = ccosh(y-ix)
  40  */
  41 /* INDENT ON */
  42
  43 #include "libm.h"
  44 #include "complex_wrapper.h"
  45
  46 dcomplex
  47 ccos(dcomplex z) {
  48         double x, y;
  49
  50         x = D_RE(z);
  51         y = D_IM(z);
  52         D_RE(z) = y;
  53         D_IM(z) = -x;
  54         return (ccosh(z));
  55 }