sysdeps/x86_64/fpu/fegetround.c

   1 /* Return current rounding direction.
   2    Copyright (C) 1997-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <fenv.h>
  21
  22 int
  23 __fegetround (void)
  24 {
  25   int cw;
  26   /* We only check the x87 FPU unit.  The SSE unit should be the same
  27      - and if it's not the same there's no way to signal it.  */
  28
  29   __asm__ ("fnstcw %0" : "=m" (*&cw));
  30
  31   return cw & 0xc00;
  32 }
  33 libm_hidden_def (__fegetround)
  34 weak_alias (__fegetround, fegetround)
  35 libm_hidden_weak (fegetround)