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63 lines
2.1 KiB
C
63 lines
2.1 KiB
C
/* Install given floating-point environment.
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Copyright (C) 1997-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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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<https://www.gnu.org/licenses/>. */
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#include <fenv.h>
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int
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__fesetenv (const fenv_t *envp)
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{
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union { unsigned long long buf[4]; fenv_t env; } temp;
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unsigned long long *bufptr;
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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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bufptr = temp.buf;
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__asm__ (
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"fstd %%fr0,0(%1)\n"
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: "=m" (temp) : "r" (bufptr) : "%r0");
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temp.env.__status_word &= ~(FE_ALL_EXCEPT
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| (FE_ALL_EXCEPT << 27)
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| FE_DOWNWARD);
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if (envp == FE_DFL_ENV)
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temp.env.__status_word = 0;
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else if (envp == FE_NOMASK_ENV)
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temp.env.__status_word |= FE_ALL_EXCEPT;
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else
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temp.env.__status_word |= (envp->__status_word
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& (FE_ALL_EXCEPT
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| FE_DOWNWARD
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| (FE_ALL_EXCEPT << 27)));
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/* Load the new environment. We use bufptr again since the
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initial asm has modified the value of the register and here
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we take advantage of that to load in reverse order so fr0
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is loaded last and T-Bit is enabled. */
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__asm__ (
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"fldd 0(%1),%%fr0\n"
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: : "m" (temp), "r" (bufptr) : "%r0" );
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/* Success. */
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return 0;
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}
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libm_hidden_def (__fesetenv)
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weak_alias (__fesetenv, fesetenv)
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libm_hidden_weak (fesetenv)
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