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>

          --- old/usr/src/lib/libm/common/Q/coshl.c
          +++ new/usr/src/lib/libm/common/Q/coshl.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      -#pragma weak coshl = __coshl
       30 +#pragma weak __coshl = coshl
  31   31  
  32   32  #include "libm.h"
  33   33  #include "longdouble.h"
  34   34  
  35   35  
  36   36  /*
  37   37   * coshl(X)
  38   38   * RETURN THE HYPERBOLIC COSINE OF X
  39   39   *
  40   40   * Method :

  41   41   *      1. Replace x by |x| (coshl(x) = coshl(-x)).
  42   42   *      2.
  43   43   *                                                     [ expl(x) - 1 ]^2
  44   44   *          0        <= x <= 0.3465 : coshl(x) := 1 + -------------------
  45   45   *                                                          2*expl(x)
  46   46   *
  47   47   *                                                expl(x) + 1/expl(x)
  48   48   *          0.3465   <= x <= thresh : coshl(x) := -------------------
  49   49   *                                                         2
  50   50   *          thresh   <= x <= lnovft : coshl(x) := expl(x)/2
  51   51   *          lnovft   <= x <  INF    : coshl(x) := scalbnl(expl(x-1024*ln2),1023)
  52   52   *
  53   53   * here
  54   54   *      thr1            a number that is near one half of ln2.
  55   55   *      thr2            a number such that
  56   56   *                              expl(thresh)+expl(-thresh)=expl(thresh)
  57   57   *      lnovft:         logrithm of the overflow threshold
  58   58   *                      = MEP1*ln2 chopped to machine precision.
  59   59   *      ME              maximum exponent
  60   60   *      MEP1            maximum exponent plus 1
  61   61   *
  62   62   * Special cases:
  63   63   *      coshl(x) is |x| if x is +INF, -INF, or NaN.
  64   64   *      only coshl(0)=1 is exact for finite x.
  65   65   */
  66   66  
  67   67  #define ME      16383
  68   68  #define MEP1    16384
  69   69  #define LNOVFT  1.135652340629414394949193107797076342845e+4L
  70   70                  /* last 32 bits of LN2HI is zero */
  71   71  #define LN2HI   6.931471805599453094172319547495844850203e-0001L
  72   72  #define LN2LO   1.667085920830552208890449330400379754169e-0025L
  73   73  #define THR1    0.3465L
  74   74  #define THR2    45.L
  75   75  
  76   76  static const long double
  77   77          half    = 0.5L,
  78   78          tinyl   = 7.5e-37L,
  79   79          one     = 1.0L,
  80   80          ln2hi   = LN2HI,
  81   81          ln2lo   = LN2LO,
  82   82          lnovftL = LNOVFT,
  83   83          thr1    = THR1,
  84   84          thr2    = THR2;
  85   85  
  86   86  long double
  87   87  coshl(long double x) {
  88   88          long double t, w;
  89   89  
  90   90          w = fabsl(x);
  91   91          if (!finitel(w))
  92   92                  return (w + w);         /* x is INF or NaN */
  93   93          if (w < thr1) {
  94   94                  t = w < tinyl ? w : expm1l(w);
  95   95                  w = one + t;
  96   96                  if (w != one)
  97   97                          w = one + (t * t) / (w + w);
  98   98                  return (w);
  99   99          } else if (w < thr2) {
 100  100                  t = expl(w);
 101  101                  return (half * (t + one / t));
 102  102          } else if (w <= lnovftL)
 103  103                  return (half * expl(w));
 104  104          else {
 105  105                  return (scalbnl(expl((w - MEP1 * ln2hi) - MEP1 * ln2lo), ME));
 106  106          }
 107  107  }

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