alpha/gen/flt_rounds.c

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