glibc/sysdeps/x86_64/fpu/fegetround.c

36 lines
1.2 KiB
C

/* Return current rounding direction.
Copyright (C) 1997-2020 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, see
<https://www.gnu.org/licenses/>. */
#include <fenv.h>
int
__fegetround (void)
{
int cw;
/* We only check the x87 FPU unit. The SSE unit should be the same
- and if it's not the same there's no way to signal it. */
__asm__ ("fnstcw %0" : "=m" (*&cw));
return cw & 0xc00;
}
libm_hidden_def (__fegetround)
weak_alias (__fegetround, fegetround)
libm_hidden_weak (fegetround)