usr/src/lib/libm/common/LD/asinhl.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 __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         volatile long double dummy;
  44
  45         w = fabsl(x);
  46         if (isnanl(x))
  47                 return (x + x); /* x is NaN */
  48         if (w < tiny) {
  49                 dummy = x + big;        /* inexact if x != 0 */
  50                 return (x);     /* tiny x */
  51         } else if (w < big) {
  52                 t = one / w;
  53                 return (copysignl(log1pl(w + w / (t + sqrtl(one + t * t))), x));
  54         } else
  55                 return (copysignl(logl(w) + ln2, x));
  56 }