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53 lines
1.5 KiB
C
53 lines
1.5 KiB
C
/* Set current rounding direction.
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Copyright (C) 1997-2015 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 <unistd.h>
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#include <ldsodefs.h>
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#include <dl-procinfo.h>
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int
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fesetround (int round)
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{
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unsigned short int cw;
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if ((round & ~0xc00) != 0)
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/* ROUND is no valid rounding mode. */
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return 1;
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__asm__ ("fnstcw %0" : "=m" (*&cw));
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cw &= ~0xc00;
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cw |= round;
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__asm__ ("fldcw %0" : : "m" (*&cw));
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/* If the CPU supports SSE we set the MXCSR as well. */
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if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
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{
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unsigned int xcw;
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__asm__ ("stmxcsr %0" : "=m" (*&xcw));
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xcw &= ~0x6000;
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xcw |= round << 3;
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__asm__ ("ldmxcsr %0" : : "m" (*&xcw));
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}
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return 0;
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}
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libm_hidden_def (fesetround)
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