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70 lines
2.1 KiB
C
70 lines
2.1 KiB
C
/* Set FP exception mask and rounding mode. Mach/Alpha version.
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Copyright (C) 2002 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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <fpu_control.h>
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#define FPCR_DYN_SHIFT 58 /* first dynamic rounding mode bit */
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#define FPCR_DYN_CHOPPED (0x0UL << FPCR_DYN_SHIFT) /* towards 0 */
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#define FPCR_DYN_MINUS (0x1UL << FPCR_DYN_SHIFT) /* towards -INF */
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#define FPCR_DYN_NORMAL (0x2UL << FPCR_DYN_SHIFT) /* towards nearest */
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#define FPCR_DYN_PLUS (0x3UL << FPCR_DYN_SHIFT) /* towards +INF */
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#define FPCR_DYN_MASK (0x3UL << FPCR_DYN_SHIFT)
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static inline unsigned long
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rdfpcr (void)
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{
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unsigned long fpcr;
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asm ("excb; mf_fpcr %0" : "=f"(fpcr));
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return fpcr;
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}
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static inline void
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wrfpcr (unsigned long fpcr)
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{
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asm volatile ("mt_fpcr %0; excb" : : "f"(fpcr));
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}
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void
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__setfpucw (fpu_control_t fpu_control)
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{
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unsigned long fpcr;
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if (!fpu_control)
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fpu_control = _FPU_DEFAULT;
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/* first, set dynamic rounding mode: */
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fpcr = rdfpcr();
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fpcr &= ~FPCR_DYN_MASK;
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switch (fpu_control & 0xc00)
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{
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case _FPU_RC_NEAREST: fpcr |= FPCR_DYN_NORMAL; break;
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case _FPU_RC_DOWN: fpcr |= FPCR_DYN_MINUS; break;
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case _FPU_RC_UP: fpcr |= FPCR_DYN_PLUS; break;
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case _FPU_RC_ZERO: fpcr |= FPCR_DYN_CHOPPED; break;
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}
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wrfpcr(fpcr);
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/* XXX trap bits? */
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__fpu_control = fpu_control; /* update global copy */
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}
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