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46 lines
1.8 KiB
C
46 lines
1.8 KiB
C
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/* 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 Richard Henderson <rth@tamu.edu>, 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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void
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fesetenv (const fenv_t *envp)
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{
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unsigned long fpcr;
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fenv_t env;
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/* Magic encoding of default values: high bit set (never possible for a
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user-space address) is not indirect. And we don't even have to get
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rid of it since we mask things around just below. */
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if ((long)envp >= 0)
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env = *envp;
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else
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env = (unsigned long)envp;
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/* Reset the rounding mode with the hardware fpcr. Note that the following
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system call is an implied trap barrier for our modification. */
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__asm__ __volatile__("excb; mf_fpcr %0" : "=f"(fpcr));
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fpcr = (fpcr & ~(3UL << 58)) | (env & (3UL << 58));
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__asm__ __volatile__("mt_fpcr %0" : : "f"(fpcr));
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/* Reset the exception status and mask with the kernel's FP code. */
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__ieee_set_fp_control(env & (FE_ALL_EXCEPT | 0x3e));
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}
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