cmf4.c

minux的源代码,一个非常小的操作系统

/*
  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
  See the copyright notice in the ACK home directory, in the file "Copyright".
*/

/* $Header: cmf4.c,v 1.6 93/01/05 12:04:14 ceriel Exp $ */

/*
	COMPARE	SINGLES (CMF 4)
*/

#include	"FP_types.h"
#include	"get_put.h"

int
cmf4(f1,f2)
SINGLE	f1,f2;
{
		/*
		 * return ((f1 < f2) ? 1 : (f1 - f2))
		 */
#define SIGN(x) (((x) < 0) ? -1 : 1)
        int	sign1,sign2;
	long	l1,l2;

	l1 = get4((char *) &f1);
	l2 = get4((char *) &f2);

	if (l1 == l2) return 0;

        sign1 = SIGN(l1);
        sign2 = SIGN(l2);
        if (sign1 != sign2) {
		if ((l1 & 0x7fffffff) == 0 &&
		    (l2 & 0x7fffffff) == 0) return 0;
                return ((sign1 > 0) ? -1 : 1);
	}

	return (sign1 * ((l1 < l2) ? 1 : -1));
}