dp_simple.c

来自「广州斯道2410普及版II的源代码」· C语言 代码 · 共 67 行

/* IEEE754 floating point arithmetic
 * double precision: common utilities
 */
/*
 * MIPS floating point support
 * Copyright (C) 1994-2000 Algorithmics Ltd.  All rights reserved.
 * http://www.algor.co.uk
 *
 * ########################################################################
 *
 *  This program is free software; you can distribute it and/or modify it
 *  under the terms of the GNU General Public License (Version 2) as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * ########################################################################
 */


#include "ieee754dp.h"

int ieee754dp_finite(ieee754dp x)
{
	return DPBEXP(x) != DP_EMAX + 1 + DP_EBIAS;
}

ieee754dp ieee754dp_copysign(ieee754dp x, ieee754dp y)
{
	CLEARCX;
	DPSIGN(x) = DPSIGN(y);
	return x;
}


ieee754dp ieee754dp_neg(ieee754dp x)
{
	CLEARCX;

	if (ieee754dp_isnan(x))	/* but not infinity */
		return ieee754dp_nanxcpt(x, "neg", x);

	/* quick fix up */
	DPSIGN(x) ^= 1;
	return x;
}


ieee754dp ieee754dp_abs(ieee754dp x)
{
	CLEARCX;

	if (ieee754dp_isnan(x))	/* but not infinity */
		return ieee754dp_nanxcpt(x, "abs", x);

	/* quick fix up */
	DPSIGN(x) = 0;
	return x;
}