82 lines
3 KiB
C
82 lines
3 KiB
C
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/* $NetBSD: flt_rounds.c,v 1.4 2007/01/17 23:24:22 hubertf Exp $ */
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/*
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* Copyright (c) 1996 Mark Brinicombe
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Mark Brinicombe
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* for the NetBSD Project.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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__RCSID("$NetBSD: flt_rounds.c,v 1.4 2007/01/17 23:24:22 hubertf Exp $");
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#endif /* LIBC_SCCS and not lint */
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#include <sys/types.h>
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#include <ieeefp.h>
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static const int map[] = {
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1, /* round to nearest */
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2, /* round to positive infinity */
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3, /* round to negative infinity */
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0 /* round to zero */
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};
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/*
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* Return the current FP rounding mode
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*
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* Returns:
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* 0 - round to zero
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* 1 - round to nearest
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* 2 - round to postive infinity
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* 3 - round to negative infinity
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*
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* ok all we need to do is get the current FP rounding mode
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* index our map table and return the appropriate value.
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*
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* HOWEVER:
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* The ARM FPA codes the rounding mode into the actual FP instructions
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* so there is no such thing as a global rounding mode.
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* The default is round to nearest if rounding is not explicitly specified.
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* FP instructions generated by GCC will not explicitly specify a rounding
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* mode.
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*
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* So the best we can do it to return the rounding mode FP instructions
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* use if rounding is not specified which is round to nearest.
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*
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* This could change in the future with new floating point emulators or
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* soft float FP libraries.
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*/
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extern int __flt_rounds __P((void));
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int
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__flt_rounds()
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{
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return(map[fpgetround()]);
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}
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