sysdeps/alpha/fpu/fesetround.c

   1 /* Set current rounding direction.
   2    Copyright (C) 1997-2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Richard Henderson <rth@tamu.edu>, 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_libc.h>
  21
  22 int
  23 __fesetround (int round)
  24 {
  25   unsigned long fpcr;
  26
  27   if (round & ~3)
  28     return 1;
  29
  30   /* Get the current state.  */
  31   __asm__ __volatile__("excb; mf_fpcr %0" : "=f"(fpcr));
  32
  33   /* Set the relevant bits.  */
  34   fpcr = ((fpcr & ~FPCR_ROUND_MASK)
  35           | ((unsigned long)round << FPCR_ROUND_SHIFT));
  36
  37   /* Put the new state in effect.  */
  38   __asm__ __volatile__("mt_fpcr %0; excb" : : "f"(fpcr));
  39
  40   return 0;
  41 }
  42 libm_hidden_def (__fesetround)
  43 weak_alias (__fesetround, fesetround)
  44 libm_hidden_weak (fesetround)