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 asinhl = __asinhl
  31 
  32 #include "libm.h"
  33 
  34 static const long double
  35         ln2     = 6.931471805599453094172321214581765680755e-0001L,
  36         one     = 1.0L,
  37         big     = 1.0e+20L,
  38         tiny    = 1.0e-20L;
  39 
  40 long double
  41 asinhl(long double x) {
  42         long double t, w;
  43 #ifndef lint
  44         volatile long double dummy;
  45 #endif
  46 
  47         w = fabsl(x);
  48         if (isnanl(x))
  49                 return (x + x); /* x is NaN */
  50         if (w < tiny) {
  51 #ifndef lint
  52                 dummy = x + big;        /* inexact if x != 0 */
  53 #endif
  54                 return (x);     /* tiny x */
  55         } else if (w < big) {
  56                 t = one / w;
  57                 return (copysignl(log1pl(w + w / (t + sqrtl(one + t * t))), x));
  58         } else
  59                 return (copysignl(logl(w) + ln2, x));
  60 }