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/tanl.c
          +++ new/usr/src/lib/libm/common/Q/tanl.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   30  /*
  31   31   * tanl(x)
  32   32   * Table look-up algorithm by K.C. Ng, November, 1989.
  33   33   *
  34   34   * kernel function:
  35   35   *      __k_tanl        ... tangent function on [-pi/4,pi/4]
  36   36   *      __rem_pio2l     ... argument reduction routine
  37   37   *
  38   38   * Method.
  39   39   *      Let S and C denote the sin and cos respectively on [-PI/4, +PI/4].
  40   40   *      1. Assume the argument x is reduced to y1+y2 = x-k*pi/2 in
  41   41   *         [-pi/2 , +pi/2], and let n = k mod 4.
  42   42   *      2. Let S=S(y1+y2), C=C(y1+y2). Depending on n, we have
  43   43   *
  44   44   *          n        sin(x)      cos(x)        tan(x)
  45   45   *     ----------------------------------------------------------
  46   46   *          0          S           C             S/C
  47   47   *          1          C          -S            -C/S
  48   48   *          2         -S          -C             S/C
  49   49   *          3         -C           S            -C/S
  50   50   *     ----------------------------------------------------------

  51   51   *
  52   52   * Special cases:
  53   53   *      Let trig be any of sin, cos, or tan.
  54   54   *      trig(+-INF)  is NaN, with signals;
  55   55   *      trig(NaN)    is that NaN;
  56   56   *
  57   57   * Accuracy:
  58   58   *      computer TRIG(x) returns trig(x) nearly rounded.
  59   59   */
  60   60  
  61      -#pragma weak tanl = __tanl
       61 +#pragma weak __tanl = tanl
  62   62  
  63   63  #include "libm.h"
  64   64  #include "longdouble.h"
  65   65  
  66   66  long double
  67   67  tanl(long double x) {
  68   68          long double y[2], z = 0.0L;
  69   69          int n, ix;
  70   70  
  71   71          ix = *(int *) &x;               /* High word of x */
  72   72          ix &= 0x7fffffff;
  73   73          if (ix <= 0x3ffe9220)           /* |x| ~< pi/4 */
  74   74                  return (__k_tanl(x, z, 0));
  75   75          else if (ix >= 0x7fff0000)      /* trig(Inf or NaN) is NaN */
  76   76                  return (x - x);
  77   77          else {                          /* argument reduction needed */
  78   78                  n = __rem_pio2l(x, y);
  79   79                  return (__k_tanl(y[0], y[1], (n & 1)));
  80   80          }
  81   81  }
    

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