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

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/* $NetBSD: fpsetround.c,v 1.12 2012/03/21 20:07:52 he 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: fpsetround.c,v 1.12 2012/03/21 20:07:52 he Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/types.h>
#include <ieeefp.h>
#ifdef __weak_alias
__weak_alias(fpsetround,_fpsetround)
#endif
fp_rnd
fpsetround(fp_rnd rnd_dir)
{
union {
double d;
uint64_t u64;
} fpcrval;
fp_rnd old;
__asm("excb; mf_fpcr %0; excb" : "=f" (fpcrval.d));
old = (fp_rnd)(fpcrval.u64 >> 58) & 0x3;
rnd_dir ^= old;
fpcrval.u64 ^= (long)rnd_dir << 58;
__asm("excb; mt_fpcr %0; excb" : : "f" (fpcrval.d));
return old;
}