xref: /src/sys/arch/m68k/fpe/fpu_getexp.c

/*	$NetBSD: fpu_getexp.c,v 1.5 2011/07/18 07:44:30 isaki Exp $	*/

/*
 * Copyright (c) 1995  Ken Nakata
 *	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. Neither the name of the author nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
 *
 *	@(#)fpu_getexp.c	10/8/95
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: fpu_getexp.c,v 1.5 2011/07/18 07:44:30 isaki Exp $");

#include <sys/types.h>

#include "fpu_emulate.h"

struct fpn *
fpu_getexp(struct fpemu *fe)
{
	struct fpn *fp = &fe->fe_f2;

	fe->fe_fpsr &= ~FPSR_EXCP; /* clear all exceptions */

	if (fp->fp_class == FPC_INF) {
		fp = fpu_newnan(fe);
		fe->fe_fpsr |= FPSR_OPERR;
	} else if (fp->fp_class == FPC_NUM) { /* a number */
		fpu_explode(fe, &fe->fe_f3, FTYPE_LNG, &fp->fp_exp);
		fp = &fe->fe_f3;
	} else if (fp->fp_class == FPC_SNAN) { /* signaling NaN */
		fe->fe_fpsr |= FPSR_SNAN;
	} /* else if fp == zero or fp == quiet NaN, return itself */
	return fp;
}

struct fpn *
fpu_getman(struct fpemu *fe)
{
	struct fpn *fp = &fe->fe_f2;

	fe->fe_fpsr &= ~FPSR_EXCP; /* clear all exceptions */

	if (fp->fp_class == FPC_INF) {
		fp = fpu_newnan(fe);
		fe->fe_fpsr |= FPSR_OPERR;
	} else if (fp->fp_class == FPC_NUM) { /* a number */
		fp->fp_exp = 0;
	} else if (fp->fp_class == FPC_SNAN) { /* signaling NaN */
		fe->fe_fpsr |= FPSR_SNAN;
	} /* else if fp == zero or fp == quiet NaN, return itself */
	return fp;
}