1/* Enable floating-point exceptions.
2 Copyright (C) 2001-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the 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 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <fenv.h>
20
21int
22feenableexcept (int excepts)
23{
24 unsigned short int new_exc, old_exc;
25 unsigned int new;
26
27 excepts &= FE_ALL_EXCEPT;
28
29 /* Get the current control word of the x87 FPU. */
30 __asm__ ("fstcw %0" : "=m" (*&new_exc));
31
32 old_exc = (~new_exc) & FE_ALL_EXCEPT;
33
34 new_exc &= ~excepts;
35 __asm__ ("fldcw %0" : : "m" (*&new_exc));
36
37 /* And now the same for the SSE MXCSR register. */
38 __asm__ ("stmxcsr %0" : "=m" (*&new));
39
40 /* The SSE exception masks are shifted by 7 bits. */
41 new &= ~(excepts << 7);
42 __asm__ ("ldmxcsr %0" : : "m" (*&new));
43
44 return old_exc;
45}
46