sysdeps/powerpc/q_feq.c

   1 /* 128-bit floating point unordered equality.
   2    Copyright (C) 1997 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <fenv_libc.h>
  21
  22 /* int _q_feq(const long double *a, const long double *b);
  23    Returns nonzero if a==b, 0 otherwise.
  24
  25    Special cases:
  26    NaNs are never equal to anything;
  27    -0 == +0;
  28    If either argument is a SNaN, we set FPSCR_VXSNAN to cause an
  29    'invalid operation' exception.
  30    */
  31
  32 int
  33 __q_feq(const unsigned a[4], const unsigned b[4])
  34 {
  35   unsigned a0, b0;
  36
  37   a0 = a[0]; b0 = b[0];
  38
  39   if ((a0 >> 16  &  0x7fff) != 0x7fff &&
  40       (b0 >> 16  &  0x7fff) != 0x7fff)
  41     {
  42       unsigned a3,b3,a2,b2,a1,b1;
  43       unsigned z, result;
  44
  45       a3 = a[3]; b3 = b[3]; a2 = a[2];
  46       b2 = b[2]; a1 = a[1]; b1 = b[1];
  47       result = ~(a3 ^ b3);
  48       result &= ~(a2 ^ b2);
  49       result &= ~(a1 ^ b1);
  50       z = a3 | a2;
  51       z |= a1;
  52       z = (z >> 1 | z | a0) & 0x7fffffff;
  53       /* 'z' is 0 iff a==0.0, otherwise between 1 and 0x7fffffff */
  54       return (result & ~(a0^b0 & ~(-z & 0x80000000)))+1;
  55     }
  56   else
  57     {
  58       /* Deal with SNaNs */
  59       if (((a0|b0) & 0x8000) == 0)
  60         {
  61           set_fpscr_bit(FPSCR_VXSNAN);
  62         }
  63       return 0;
  64     }
  65 }