xref: /src/lib/libc/arch/powerpc/gen/flt_rounds.c

/*	$NetBSD: flt_rounds.c,v 1.12 2015/03/19 21:22:59 joerg Exp $	*/

/*
 * Copyright (c) 1996 Mark Brinicombe
 * 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 by Mark Brinicombe
 *	for the NetBSD Project.
 * 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.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: flt_rounds.c,v 1.12 2015/03/19 21:22:59 joerg Exp $");
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"
#include <ieeefp.h>
#include <float.h>
#include <stdint.h>
#include <powerpc/fpu.h>

static const int map[] = {
	1,	/* round to nearest */
	0,	/* round to zero */
	2,	/* round to positive infinity */
	3	/* round to negative infinity */
};

int
__flt_rounds(void)
{
#ifdef _SOFT_FLOAT
	return map[fpgetround()];
#else
	union {
		double u_d;
		uint64_t u_fpscr;
	} ud;

	__asm volatile("mffs %0" : "=f"(ud.u_d));
	return map[((uint32_t)ud.u_fpscr & FPSCR_RN)];
#endif
}