minix/lib/libc/arch/alpha/gen/flt_rounds.c

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/* $NetBSD: flt_rounds.c,v 1.9 2011/06/12 05:44:36 matt Exp $ */
/*
* Copyright (c) 1995 Christopher G. Demetriou
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed for the
* NetBSD Project. See http://www.NetBSD.org/ for
* information about NetBSD.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: flt_rounds.c,v 1.9 2011/06/12 05:44:36 matt Exp $");
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <machine/ieeefp.h>
#include <machine/float.h>
/*
* These come from <float.h> defintion
*/
#define FLT_ROUND_MAP \
( (0 << (FP_RZ*2)) /* round to zero */ \
| (1 << (FP_RN*2)) /* round to nearest */ \
| (3 << (FP_RM*2)) /* round to negative infinity */ \
| (2 << (FP_RP*2))) /* round to positive infinity */
int
__flt_rounds(void)
{
union {
double d;
uint64_t u64;
} fpcrval;
uint64_t old;
__asm("excb; mf_fpcr %0; excb" : "=f" (fpcrval.d));
old = (fpcrval.u64 >> 58) & 3;
return (FLT_ROUND_MAP >> (old << 1)) & 3;
}