glibc/sysdeps/i386/fpu/feenablxcpt.c

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/* Enable floating-point exceptions.
Copyright (C) 1999, 2000, 2003 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Andreas Jaeger <aj@suse.de>, 1999.
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>
#include <unistd.h>
#include <ldsodefs.h>
#include <dl-procinfo.h>
int
feenableexcept (int excepts)
{
unsigned short int new_exc;
unsigned short int old_exc;
/* Get the current control word. */
__asm__ ("fstcw %0" : "=m" (*&new_exc));
excepts &= FE_ALL_EXCEPT;
old_exc = (~new_exc) & FE_ALL_EXCEPT;
new_exc &= ~excepts;
__asm__ ("fldcw %0" : : "m" (*&new_exc));
/* If the CPU supports SSE we set the MXCSR as well. */
if ((GL(dl_hwcap_mask) & HWCAP_I386_XMM) != 0)
{
unsigned int xnew_exc;
/* Get the current control word. */
__asm__ ("ldmxcsr %0" : "=m" (*&xnew_exc));
xnew_exc &= ~excepts;
__asm__ ("stmxcsr %0" : : "m" (*&xnew_exc));
}
return old_exc;
}