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70 lines
2.2 KiB
C
70 lines
2.2 KiB
C
/* Set given exception flags. i386 version.
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Copyright (C) 2016-2024 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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#include <ldsodefs.h>
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int
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fesetexcept (int excepts)
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{
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/* The flags can be set in the 387 unit or in the SSE unit. To set a flag,
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it is sufficient to do it in the SSE unit, because that is guaranteed to
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not trap. However, on i386 CPUs that have only a 387 unit, set the flags
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in the 387, as long as this cannot trap. */
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excepts &= FE_ALL_EXCEPT;
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if (CPU_FEATURE_USABLE (SSE))
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{
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/* Get the control word of the SSE unit. */
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unsigned int mxcsr;
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__asm__ ("stmxcsr %0" : "=m" (*&mxcsr));
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/* Set relevant flags. */
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mxcsr |= excepts;
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/* Put the new data in effect. */
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__asm__ ("ldmxcsr %0" : : "m" (*&mxcsr));
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}
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else
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{
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fenv_t temp;
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/* Note: fnstenv masks all floating-point exceptions until the fldenv
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or fldcw below. */
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__asm__ ("fnstenv %0" : "=m" (*&temp));
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/* Set relevant flags. */
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temp.__status_word |= excepts;
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if ((~temp.__control_word) & excepts)
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{
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/* Setting the exception flags may trigger a trap (at the next
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floating-point instruction, but that does not matter).
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ISO C23 (7.6.4.4) does not allow it. */
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__asm__ volatile ("fldcw %0" : : "m" (*&temp.__control_word));
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return -1;
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}
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/* Store the new status word (along with the rest of the environment). */
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__asm__ ("fldenv %0" : : "m" (*&temp));
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}
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return 0;
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}
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