1/* Set floating-point environment exception handling.
2 Copyright (C) 2001-2020 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#include <math.h>
21
22int
23fesetexceptflag (const fexcept_t *flagp, int excepts)
24{
25 fenv_t temp;
26 unsigned int mxcsr;
27
28 /* XXX: Do we really need to set both the exception in both units?
29 Shouldn't it be enough to set only the SSE unit? */
30
31 /* Get the current x87 FPU environment. We have to do this since we
32 cannot separately set the status word. */
33 __asm__ ("fnstenv %0" : "=m" (*&temp));
34
35 temp.__status_word &= ~(excepts & FE_ALL_EXCEPT);
36 temp.__status_word |= *flagp & excepts & FE_ALL_EXCEPT;
37
38 /* Store the new status word (along with the rest of the environment.
39 Possibly new exceptions are set but they won't get executed unless
40 the next floating-point instruction. */
41 __asm__ ("fldenv %0" : : "m" (*&temp));
42
43 /* And now the same for SSE. */
44 __asm__ ("stmxcsr %0" : "=m" (*&mxcsr));
45
46 mxcsr &= ~(excepts & FE_ALL_EXCEPT);
47 mxcsr |= *flagp & excepts & FE_ALL_EXCEPT;
48
49 __asm__ ("ldmxcsr %0" : : "m" (*&mxcsr));
50
51 /* Success. */
52 return 0;
53}
54