1 /* Set floating-point environment exception handling.
2 Copyright (C) 2001-2017 Free Software Foundation, Inc.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
17
18 #include <fenv.h>
19 #include <math.h>
20
21 int
fesetexceptflag(const fexcept_t * flagp,int excepts)22 fesetexceptflag (const fexcept_t *flagp, int excepts)
23 {
24 fenv_t temp;
25 unsigned int mxcsr;
26
27 /* XXX: Do we really need to set both the exception in both units?
28 Shouldn't it be enough to set only the SSE unit? */
29
30 /* Get the current x87 FPU environment. We have to do this since we
31 cannot separately set the status word. */
32 __asm__ ("fnstenv %0" : "=m" (*&temp));
33
34 temp.__status_word &= ~(excepts & FE_ALL_EXCEPT);
35 temp.__status_word |= *flagp & excepts & FE_ALL_EXCEPT;
36
37 /* Store the new status word (along with the rest of the environment.
38 Possibly new exceptions are set but they won't get executed unless
39 the next floating-point instruction. */
40 __asm__ ("fldenv %0" : : "m" (*&temp));
41
42 /* And now the same for SSE. */
43 __asm__ ("stmxcsr %0" : "=m" (*&mxcsr));
44
45 mxcsr &= ~(excepts & FE_ALL_EXCEPT);
46 mxcsr |= *flagp & excepts & FE_ALL_EXCEPT;
47
48 __asm__ ("ldmxcsr %0" : : "m" (*&mxcsr));
49
50 /* Success. */
51 return 0;
52 }
53