5261 libm should stop using synonyms.h
5298 fabs is 0-sized, confuses dis(1) and others
Reviewed by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Approved by: Gordon Ross <gwr@nexenta.com>
5262 libm needs to be carefully unifdef'd
5268 libm doesn't need to hide symbols which are already local
Reviewed by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com>
Reviewed by: Gordon Ross <gwr@nexenta.com>
Approved by: Gordon Ross <gwr@nexenta.com>

          --- old/usr/src/lib/libm/common/Q/tanhl.c
          +++ new/usr/src/lib/libm/common/Q/tanhl.c

   1    1  /*
   2    2   * CDDL HEADER START
   3    3   *
   4    4   * The contents of this file are subject to the terms of the
   5    5   * Common Development and Distribution License (the "License").
   6    6   * You may not use this file except in compliance with the License.
   7    7   *
   8    8   * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9    9   * or http://www.opensolaris.org/os/licensing.
  10   10   * See the License for the specific language governing permissions
  11   11   * and limitations under the License.
  12   12   *
  13   13   * When distributing Covered Code, include this CDDL HEADER in each
  14   14   * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15   15   * If applicable, add the following below this CDDL HEADER, with the
  16   16   * fields enclosed by brackets "[]" replaced with your own identifying
  17   17   * information: Portions Copyright [yyyy] [name of copyright owner]
  18   18   *
  19   19   * CDDL HEADER END

  20   20   */
  21   21  
  22   22  /*
  23   23   * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  24   24   */
  25   25  /*
  26   26   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  27   27   * Use is subject to license terms.
  28   28   */
  29   29  
  30      -#if defined(ELFOBJ)
  31      -#pragma weak tanhl = __tanhl
  32      -#endif
       30 +#pragma weak __tanhl = tanhl
  33   31  
  34   32  /*
  35   33   * tanhl(x) returns the hyperbolic tangent of x
  36   34   *
  37   35   * Method :
  38   36   *      1. reduce x to non-negative:  tanhl(-x) = - tanhl(x).
  39   37   *      2.
  40   38   *        0      <  x <=  small    :  tanhl(x) := x
  41   39   *                                                -expm1l(-2x)
  42   40   *        small  <  x <=  1        :  tanhl(x) := --------------

  43   41   *                                               expm1l(-2x) + 2
  44   42   *                                                        2
  45   43   *        1      <= x <= threshold :  tanhl(x) := 1 -  ---------------
  46   44   *                                                    expm1l(2x) + 2
  47   45   *     threshold <  x <= INF       :  tanhl(x) := 1.
  48   46   *
  49   47   * where
  50   48   *      single :        small = 1.e-5           threshold = 11.0
  51   49   *      double :        small = 1.e-10          threshold = 22.0
  52   50   *      quad   :        small = 1.e-20          threshold = 45.0
  53   51   *
  54   52   * Note: threshold was chosen so that
  55   53   *              fl(1.0+2/(expm1(2*threshold)+2)) == 1.
  56   54   *
  57   55   * Special cases:
  58   56   *      tanhl(NaN) is NaN;
  59   57   *      only tanhl(0.0)=0.0 is exact for finite argument.
  60   58   */
  61   59  
  62   60  #include "libm.h"
  63   61  #include "longdouble.h"
  64   62  
  65   63  static const long double small = 1.0e-20L, one = 1.0, two = 2.0,
  66   64  #ifndef lint
  67   65          big = 1.0e+20L,
  68   66  #endif
  69   67          threshold = 45.0L;
  70   68  
  71   69  long double
  72   70  tanhl(long double x) {
  73   71          long double t, y, z;
  74   72          int signx;
  75   73          volatile long double dummy;
  76   74  
  77   75          if (isnanl(x))
  78   76                  return (x + x);         /* x is NaN */
  79   77          signx = signbitl(x);
  80   78          t = fabsl(x);
  81   79          z = one;
  82   80          if (t <= threshold) {
  83   81                  if (t > one)
  84   82                          z = one - two / (expm1l(t + t) + two);
  85   83                  else if (t > small) {
  86   84                          y = expm1l(-t - t);
  87   85                          z = -y / (y + two);
  88   86                  } else {
  89   87  #ifndef lint
  90   88                          dummy = t + big;
  91   89                                                          /* inexact if t != 0 */
  92   90  #endif
  93   91                          return (x);
  94   92                  }
  95   93          } else if (!finitel(t))
  96   94                  return (copysignl(one, x));
  97   95          else
  98   96                  return (signx ? -z + small * small : z - small * small);
  99   97          return (signx ? -z : z);
 100   98  }

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