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 2006 Sun Microsystems, Inc.  All rights reserved.
  28  * Use is subject to license terms.
  29  */
  30 
  31 #pragma weak __cacosh = cacosh
  32 
  33 
  34 /*
  35  * dcomplex cacosh(dcomplex z);
  36  *      cacosh z = +-i cacos z .
  37  * In order to make conj(cacosh(z))=cacosh(conj(z)),
  38  * we define
  39  *      cacosh z = sign(Im(z))*i cacos z .
  40  *
  41  */
  42 
  43 #include "libm.h"                       /* fabs/isnan/isinf/signbit */
  44 #include "complex_wrapper.h"
  45 
  46 /* need to work on special cases according to spec */
  47 
  48 dcomplex
  49 cacosh(dcomplex z)
  50 {
  51         dcomplex w, ans;
  52         double x, y;
  53 
  54         w = cacos(z);
  55         x = D_RE(z);
  56         y = D_IM(z);
  57 
  58         if (isnan(y)) {
  59                 D_IM(ans) = y + y;
  60 
  61                 if (isinf(x))
  62                         D_RE(ans) = fabs(x);
  63                 else
  64                         D_RE(ans) = y;
  65         } else if (signbit(y) == 0) {
  66                 D_RE(ans) = -D_IM(w);
  67                 D_IM(ans) = D_RE(w);
  68         } else {
  69                 D_RE(ans) = D_IM(w);
  70                 D_IM(ans) = -D_RE(w);
  71         }
  72 
  73         return (ans);
  74 }