1 /* Store current floating-point environment and clear exceptions.
2    Copyright (C) 1997-2022 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
__feholdexcept(fenv_t * envp)25 __feholdexcept (fenv_t *envp)
26 {
27   /* Store the environment.  Recall that fnstenv has a side effect of
28      masking all exceptions.  Then clear all exceptions.  */
29   __asm__ volatile ("fnstenv %0; fnclex" : "=m" (*envp));
30 
31   /* If the CPU supports SSE we set the MXCSR as well.  */
32   if (CPU_FEATURE_USABLE (SSE))
33     {
34       unsigned int xwork;
35 
36       /* Get the current control word.  */
37       __asm__ ("stmxcsr %0" : "=m" (envp->__eip));
38 
39       /* Set all exceptions to non-stop and clear them.  */
40       xwork = (envp->__eip | 0x1f80) & ~0x3f;
41 
42       __asm__ ("ldmxcsr %0" : : "m" (*&xwork));
43     }
44 
45   return 0;
46 }
47 libm_hidden_def (__feholdexcept)
48 weak_alias (__feholdexcept, feholdexcept)
49 libm_hidden_weak (feholdexcept)
50