sysdeps/unix/sysv/linux/i386/setfpucw.c

   1 /* Copyright (C) 1993 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3 Contributed by Olaf Flebbe.
   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
  17 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18 Boston, MA 02111-1307, USA.  */
  19
  20 #include <fpu_control.h>
  21
  22 void
  23 __setfpucw (fpu_control)
  24      unsigned short fpu_control;
  25 {
  26   volatile unsigned short cw;
  27
  28   /* If user supplied _fpu_control, use it ! */
  29   if (!fpu_control)
  30   {
  31     /* use linux defaults */
  32     fpu_control = _FPU_DEFAULT;
  33   }
  34   /* Get Control Word */
  35   __asm__ volatile ("fnstcw %0" : "=m" (cw) : );
  36
  37   /* mask in */
  38   cw &= _FPU_RESERVED;
  39   cw = cw | (fpu_control & ~_FPU_RESERVED);
  40
  41   /* set cw */
  42   __asm__ volatile ("fldcw %0" :: "m" (cw));
  43 }