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/* Install given floating-point control modes. x86_64 version.
Copyright (C) 2016-2021 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
<https://www.gnu.org/licenses/>. */
#include <fenv.h>
#include <fpu_control.h>
/* All exceptions, including the x86-specific "denormal operand"
exception. */
#define FE_ALL_EXCEPT_X86 (FE_ALL_EXCEPT | __FE_DENORM)
int
fesetmode (const femode_t *modep)
{
fpu_control_t cw;
unsigned int mxcsr;
__asm__ ("stmxcsr %0" : "=m" (mxcsr));
/* Preserve SSE exception flags but restore other state in
MXCSR. */
mxcsr &= FE_ALL_EXCEPT_X86;
if (modep == FE_DFL_MODE)
{
cw = _FPU_DEFAULT;
/* Default MXCSR state has all bits zero except for those
masking exceptions. */
mxcsr |= FE_ALL_EXCEPT_X86 << 7;
}
else
{
cw = modep->__control_word;
mxcsr |= modep->__mxcsr & ~FE_ALL_EXCEPT_X86;
}
_FPU_SETCW (cw);
__asm__ ("ldmxcsr %0" : : "m" (mxcsr));
return 0;
}
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