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/exp2l.c
          +++ new/usr/src/lib/libm/common/Q/exp2l.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 exp2l = __exp2l
       30 +#pragma weak __exp2l = exp2l
  31   31  
  32   32  #include "libm.h"
  33   33  #include "longdouble.h"
  34   34  
  35   35  /*
  36   36   *      exp2l(x) = 2**x = 2**((x-anint(x))+anint(x))
  37   37   *               = 2**anint(x)*2**(x-anint(x))
  38   38   *               = 2**anint(x)*exp((x-anint(x))*ln2)
  39   39   */
  40   40  

  41   41  #define TINY    1.0e-20L        /* single: 1e-5, double: 1e-10, quad: 1e-20 */
  42   42  #define OVFLEXP 16400           /* single: 130,  double  1030,  quad: 16400 */
  43   43  #define UNFLEXP -16520          /* single:-155,  double -1080,  quad:-16520 */
  44   44  
  45   45  static const long double
  46   46          zero = 0.0L,
  47   47          tiny = TINY * TINY,
  48   48          half = 0.5L,
  49   49          ln2 = 6.931471805599453094172321214581765680755e-0001L,
  50   50          one = 1.0L;
  51   51  
  52   52  static const int
  53   53          ovflexp = OVFLEXP,
  54   54          unflexp = UNFLEXP;
  55   55  
  56   56  long double
  57   57  exp2l(long double x) {
  58   58          long double t;
  59   59  
  60   60          if (!finitel(x)) {
  61   61                  if (isnanl(x) || x > zero)
  62   62                          return (x + x);
  63   63                  else
  64   64                          return (zero);
  65   65          }
  66   66          t = fabsl(x);
  67   67          if (t < half) {
  68   68                  if (t < tiny)
  69   69                          return (one + x);
  70   70                  else
  71   71                          return (expl(ln2 * x));
  72   72          }
  73   73          t = anintl(x);
  74   74          if (t < ovflexp) {
  75   75                  if (t >= unflexp)
  76   76                          return (scalbnl(expl(ln2 * (x - t)), (int) t));
  77   77                  else
  78   78                          return (scalbnl(one, unflexp)); /* underflow */
  79   79          } else
  80   80                  return (scalbnl(one, ovflexp)); /* overflow  */
  81   81  }

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