glibc/sysdeps/i386/fpu/fesetround.c

39 lines
1.2 KiB
C

/* Set current rounding direction.
Copyright (C) 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <fenv.h>
int
fesetround (int round)
{
unsigned short int cw;
if ((round & ~0xc00) != 0)
/* ROUND is no valid rounding mode. */
return 1;
__asm__ ("fnstcw %0" : "=m" (*&cw));
cw &= ~0xc00;
cw |= round;
__asm__ ("fldcw %0" : : "m" (*&cw));
return 0;
}