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/* Install given floating-point environment and raise exceptions.
Copyright (C) 1997-2022 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>
#include <arm-features.h>
int
__feupdateenv (const fenv_t *envp)
{
fpu_control_t fpscr, new_fpscr, updated_fpscr;
int excepts;
/* Fail if a VFP unit isn't present. */
if (!ARM_HAVE_VFP)
return 1;
_FPU_GETCW (fpscr);
excepts = fpscr & FE_ALL_EXCEPT;
if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV))
{
/* Merge current exception flags with the saved fenv. */
new_fpscr = envp->__cw | excepts;
/* Write new FPSCR if different (ignoring NZCV flags). */
if (((fpscr ^ new_fpscr) & ~_FPU_MASK_NZCV) != 0)
_FPU_SETCW (new_fpscr);
/* Raise the exceptions if enabled in the new FP state. */
if (excepts & (new_fpscr >> FE_EXCEPT_SHIFT))
return __feraiseexcept (excepts);
return 0;
}
/* Preserve the reserved FPSCR flags. */
new_fpscr = fpscr & (_FPU_RESERVED | FE_ALL_EXCEPT);
new_fpscr |= (envp == FE_DFL_ENV) ? _FPU_DEFAULT : _FPU_IEEE;
if (((new_fpscr ^ fpscr) & ~_FPU_MASK_NZCV) != 0)
{
_FPU_SETCW (new_fpscr);
/* Not all VFP architectures support trapping exceptions, so
test whether the relevant bits were set and fail if not. */
_FPU_GETCW (updated_fpscr);
if (new_fpscr & ~updated_fpscr)
return 1;
}
/* Raise the exceptions if enabled in the new FP state. */
if (excepts & (new_fpscr >> FE_EXCEPT_SHIFT))
return __feraiseexcept (excepts);
return 0;
}
libm_hidden_def (__feupdateenv)
weak_alias (__feupdateenv, feupdateenv)
libm_hidden_weak (feupdateenv)
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