5261 libm should stop using synonyms.h

          --- old/usr/src/lib/libm/common/C/logb.c
          +++ new/usr/src/lib/libm/common/C/logb.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 logb = __logb
  31      -#pragma weak _logb = __logb
       30 +#pragma weak __logb = logb
       31 +#pragma weak _logb = logb
  32   32  
  33   33  #include "libm.h"
  34   34  #include "xpg6.h"       /* __xpg6 */
  35   35  #define _C99SUSv3_logb  _C99SUSv3_logb_subnormal_is_like_ilogb
  36   36  
  37   37  #if defined(__x86)
  38   38  static const double two52 = 4503599627370496.0;
  39   39  #else
  40   40  /*
  41   41   * v: high part of a non-zero subnormal |x|; w: low part of |x|

  42   42   */
  43   43  static int
  44   44  ilogb_subnormal(unsigned v, unsigned w) {
  45   45          int r = -1022 - 52;
  46   46  
  47   47          if (v)
  48   48                  r += 32;
  49   49          else
  50   50                  v = w;
  51   51          if (v & 0xffff0000)
  52   52                  r += 16, v >>= 16;
  53   53          if (v & 0xff00)
  54   54                  r += 8, v >>= 8;
  55   55          if (v & 0xf0)
  56   56                  r += 4, v >>= 4;
  57   57          v <<= 1;
  58   58          return (r + ((0xffffaa50 >> v) & 0x3));
  59   59  }
  60   60  #endif  /* defined(__x86) */
  61   61  
  62   62  double
  63   63  logb(double x) {
  64   64          int *px = (int *) &x, k = px[HIWORD] & ~0x80000000;
  65   65  
  66   66          if (k < 0x00100000) {
  67   67                  if ((px[LOWORD] | k) == 0)
  68   68                          return (_SVID_libm_err(x, x, 45));
  69   69                  else if ((__xpg6 & _C99SUSv3_logb) != 0) {
  70   70  #if defined(__x86)
  71   71                          x *= two52;
  72   72                          return ((double) (((px[HIWORD] & 0x7ff00000) >> 20)
  73   73                                  - 1075));
  74   74  #else
  75   75                          return ((double) ilogb_subnormal(k, px[LOWORD]));
  76   76  #endif
  77   77                  } else
  78   78                          return (-1022.0);
  79   79          } else if (k < 0x7ff00000)
  80   80                  return ((double) ((k >> 20) - 1023));
  81   81          else
  82   82                  return (x * x);
  83   83  }

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