glibc/sysdeps/x86_64/fpu/fedisblxcpt.c

46 lines
1.4 KiB
C

/* Disable floating-point exceptions.
Copyright (C) 2001-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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
fedisableexcept (int excepts)
{
unsigned short int new_exc, old_exc;
unsigned int new;
excepts &= FE_ALL_EXCEPT;
/* Get the current control word of the x87 FPU. */
__asm__ ("fstcw %0" : "=m" (*&new_exc));
old_exc = (~new_exc) & FE_ALL_EXCEPT;
new_exc |= excepts;
__asm__ ("fldcw %0" : : "m" (*&new_exc));
/* And now the same for the SSE MXCSR register. */
__asm__ ("stmxcsr %0" : "=m" (*&new));
/* The SSE exception masks are shifted by 7 bits. */
new |= excepts << 7;
__asm__ ("ldmxcsr %0" : : "m" (*&new));
return old_exc;
}