77 lines
2.5 KiB
C
77 lines
2.5 KiB
C
/* Install given floating-point environment.
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Copyright (C) 1997 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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <fenv.h>
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#include <assert.h>
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void
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fesetenv (const fenv_t *envp)
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{
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fenv_t temp;
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/* The memory block used by fstenv/fldenv has a size of 28 bytes. */
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assert (sizeof (fenv_t) == 28);
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/* Install the environment specified by ENVP. But there are a few
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values which we do not want to come from the saved environment.
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Therefore, we get the current environment and replace the values
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we want to use from the environment specified by the parameter. */
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__asm__ ("fnstenv %0" : "=m" (*&temp));
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if (envp == FE_DFL_ENV)
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{
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temp.control_word |= FE_ALL_EXCEPT;
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temp.control_word &= ~FE_TOWARDSZERO;
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temp.status_word &= ~FE_ALL_EXCEPT;
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temp.eip = 0;
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temp.cs_selector = 0;
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temp.opcode = 0;
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temp.data_offset = 0;
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temp.data_selector = 0;
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}
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else if (envp == FE_NOMASK_ENV)
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{
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temp.control_word &= ~(FE_ALL_EXCEPT | FE_TOWARDSZERO);
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temp.status_word &= ~FE_ALL_EXCEPT;
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temp.eip = 0;
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temp.cs_selector = 0;
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temp.opcode = 0;
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temp.data_offset = 0;
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temp.data_selector = 0;
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}
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else
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{
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temp.control_word &= ~(FE_ALL_EXCEPT | FE_TOWARDSZERO);
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temp.control_word |= (envp->control_word
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& (FE_ALL_EXCEPT | FE_TOWARDSZERO));
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temp.status_word &= ~FE_ALL_EXCEPT;
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temp.status_word |= envp->status_word & FE_ALL_EXCEPT;
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temp.eip = envp->eip;
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temp.cs_selector = envp->cs_selector;
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temp.opcode = envp->opcode;
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temp.data_offset = envp->data_offset;
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temp.data_selector = envp->data_selector;
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}
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__asm__ ("fldenv %0" : : "m" (temp));
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}
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