glibc/sysdeps/x86_64/fpu/feholdexcpt.c

42 lines
1.4 KiB
C

/* Store current floating-point environment and clear exceptions.
Copyright (C) 2001-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <fenv.h>
int
__feholdexcept (fenv_t *envp)
{
unsigned int mxcsr;
/* Store the environment. Recall that fnstenv has a side effect of
masking all exceptions. Then clear all exceptions. */
__asm__ ("fnstenv %0\n\t"
"stmxcsr %1\n\t"
"fnclex"
: "=m" (*envp), "=m" (envp->__mxcsr));
/* Set the SSE MXCSR register. */
mxcsr = (envp->__mxcsr | 0x1f80) & ~0x3f;
__asm__ ("ldmxcsr %0" : : "m" (*&mxcsr));
return 0;
}
libm_hidden_def (__feholdexcept)
weak_alias (__feholdexcept, feholdexcept)
libm_hidden_weak (feholdexcept)