1 /* Disable floating-point exceptions.
2    Copyright (C) 1999-2022 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 <unistd.h>
21 #include <ldsodefs.h>
22 #include <dl-procinfo.h>
23 
24 int
fedisableexcept(int excepts)25 fedisableexcept (int excepts)
26 {
27   unsigned short int new_exc, old_exc;
28 
29   /* Get the current control word.  */
30   __asm__ ("fstcw %0" : "=m" (*&new_exc));
31 
32   old_exc = (~new_exc) & FE_ALL_EXCEPT;
33 
34   excepts &= FE_ALL_EXCEPT;
35 
36   new_exc |= excepts;
37   __asm__ ("fldcw %0" : : "m" (*&new_exc));
38 
39   /* If the CPU supports SSE we set the MXCSR as well.  */
40   if (CPU_FEATURE_USABLE (SSE))
41     {
42       unsigned int xnew_exc;
43 
44       /* Get the current control word.  */
45       __asm__ ("stmxcsr %0" : "=m" (*&xnew_exc));
46 
47       xnew_exc |= excepts << 7;
48 
49       __asm__ ("ldmxcsr %0" : : "m" (*&xnew_exc));
50     }
51 
52   return old_exc;
53 }
54