11175 libm should use signbit() correctly
11188 c99 math macros should return strictly backward compatible values

          --- old/usr/src/lib/libm/common/LD/__rem_pio2l.c
          +++ new/usr/src/lib/libm/common/LD/__rem_pio2l.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      -/* __rem_pio2l(x,y)
       30 +/*
       31 + * __rem_pio2l(x,y)
  31   32   *
  32   33   * return the remainder of x rem pi/2 in y[0]+y[1]
  33   34   * by calling __rem_pio2m
  34   35   */
  35   36  
  36   37  #include "libm.h"
  37   38  #include "longdouble.h"
  38   39  
  39   40  extern const int _TBL_ipio2l_inf[];
  40   41  

  41   42  static const long double
  42   43      two24l = 16777216.0L,
  43   44      pio4   = 0.7853981633974483096156608458198757210495L;
  44   45  
  45   46  int
  46   47  __rem_pio2l(long double x, long double *y)
  47   48  {
  48   49          long double     z, w;
  49   50          double          t[3], v[5];
  50   51          int             e0, i, nx, n, sign;
  51   52  
  52   53          sign = signbitl(x);
  53   54          z = fabsl(x);
  54   55          if (z <= pio4) {
  55   56                  y[0] = x;
  56   57                  y[1] = 0;
  57   58                  return (0);
  58   59          }
  59   60          e0 = ilogbl(z) - 23;
  60   61          z = scalbnl(z, -e0);
  61   62          for (i = 0; i < 3; i++) {
  62   63                  t[i] = (double)((int)(z));

  63   64                  z = (z - (long double)t[i]) * two24l;
  64   65          }
  65   66          nx = 3;
  66   67          while (t[nx-1] == 0.0)
  67   68                  nx--;   /* omit trailing zeros */
  68   69          n = __rem_pio2m(t, v, e0, nx, 2, _TBL_ipio2l_inf);
  69   70          z = (long double)v[1];
  70   71          w = (long double)v[0];
  71   72          y[0] = z + w;
  72   73          y[1] = z - (y[0] - w);
  73      -        if (sign == 1) {
       74 +        if (sign != 0) {
  74   75                  y[0] = -y[0];
  75   76                  y[1] = -y[1];
  76   77                  return (-n);
  77   78          }
  78   79          return (n);
  79   80  }
    

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX