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79 lines
2.4 KiB
C
79 lines
2.4 KiB
C
/* Install given floating-point environment and raise exceptions.
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Copyright (C) 1997-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#include <fenv.h>
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#include <fpu_control.h>
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#include <arm-features.h>
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int
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__feupdateenv (const fenv_t *envp)
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{
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fpu_control_t fpscr, new_fpscr, updated_fpscr;
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int excepts;
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/* Fail if a VFP unit isn't present. */
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if (!ARM_HAVE_VFP)
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return 1;
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_FPU_GETCW (fpscr);
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excepts = fpscr & FE_ALL_EXCEPT;
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if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV))
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{
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/* Merge current exception flags with the saved fenv. */
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new_fpscr = envp->__cw | excepts;
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/* Write new FPSCR if different (ignoring NZCV flags). */
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if (((fpscr ^ new_fpscr) & ~_FPU_MASK_NZCV) != 0)
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_FPU_SETCW (new_fpscr);
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/* Raise the exceptions if enabled in the new FP state. */
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if (excepts & (new_fpscr >> FE_EXCEPT_SHIFT))
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return __feraiseexcept (excepts);
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return 0;
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}
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/* Preserve the reserved FPSCR flags. */
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new_fpscr = fpscr & (_FPU_RESERVED | FE_ALL_EXCEPT);
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new_fpscr |= (envp == FE_DFL_ENV) ? _FPU_DEFAULT : _FPU_IEEE;
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if (((new_fpscr ^ fpscr) & ~_FPU_MASK_NZCV) != 0)
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{
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_FPU_SETCW (new_fpscr);
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/* Not all VFP architectures support trapping exceptions, so
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test whether the relevant bits were set and fail if not. */
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_FPU_GETCW (updated_fpscr);
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if (new_fpscr & ~updated_fpscr)
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return 1;
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}
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/* Raise the exceptions if enabled in the new FP state. */
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if (excepts & (new_fpscr >> FE_EXCEPT_SHIFT))
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return __feraiseexcept (excepts);
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return 0;
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}
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libm_hidden_def (__feupdateenv)
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weak_alias (__feupdateenv, feupdateenv)
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libm_hidden_weak (feupdateenv)
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