adf and sbf did not work with 0.0

mach/proto/fp/adf4.c

@@ -18,6 +18,13 @@ _float	s1,s2;
 	EXTEND	e1,e2;
 	int	swap = 0;
 
+	if (s1 == (_float) 0) {
+		s1 = s2;
+		return s1;
+	}
+	if (s2 == (_float) 0) {
+		return s1;
+	}
 	extend((_double *)&s1,&e1,sizeof(SINGLE));
 	extend((_double *)&s2,&e2,sizeof(SINGLE));
 			/* if signs differ do subtraction	*/

mach/proto/fp/adf8.c

@@ -17,6 +17,15 @@ _double	s1,s2;
 {
 	EXTEND	e1,e2;
 	short	swap;
+
+	if (s1.__double[0] == 0 && s1.__double[1] == 0) {
+		s1 = s2;
+		return s1;
+	}
+	if (s2.__double[0] == 0 && s2.__double[1] == 0) {
+		return s1;
+	}
+
 	extend(&s1,&e1,sizeof(_double));
 	extend(&s2,&e2,sizeof(_double));
 #ifdef	PRT_EXT

mach/proto/fp/cmf8.c

@@ -22,25 +22,27 @@ _double	d1,d2;
 		 */
 	long	l1,l2;
 	int	sign1,sign2;
+	int	rv;
 
 	l1 = get4((char *)&d1);
 	l2 = get4((char *)&d2);
 	sign1 = SIGN(l1);
 	sign2 = SIGN(l2);
-	if (sign1 != sign2)
+	if (sign1 != sign2) {
 		return ((sign1 > 0) ? -1 : 1);
+	}
 	if (l1 != l2)	{	/* we can decide here */
-		return sign1 * (l1 < l2 ? 1 : -1) ;
+		rv = l1 < l2 ? 1 : -1;
 	}
 	else	{ 		/* decide in 2nd half */
 		l1 = get4(((char *)&d1 + 4));
 		l2 = get4(((char *)&d2 + 4));
 		if (l1 == l2)
 			return(0);
-		if (l1 < 0)
-			return l2 < 0 ? l2 > l1 : -1;
-		if (l2 < 0)
-			return 1;
-		return l2 > l1 ? 1 : -1;
+		if (l1 >= 0)
+			rv = l1 < l2 || l2 < 0 ? 1 : -1;
+		else if (l2 >= 0) rv = -1;
+		else rv = l1 < l2 ? 1 : -1;
 	}
+	return sign1 * rv;
 }

mach/proto/fp/sbf4.c

@@ -22,6 +22,9 @@ _float	s1,s2;
 				/*		s2 = -s2	*/
 	char unsigned *p;
 
+	if (s2 == (_float) 0) {
+		return s1;
+	}
 	p = (char unsigned *) &s2;
 	*p ^= 0x80;	/* change sign of s2 */
 	s1 = adf4(s2,s1);

mach/proto/fp/sbf8.c

@@ -25,6 +25,9 @@ _double	s1,s2;
 #ifdef	PRT_EXT
 	fprintf(stderr,"SBF8 ():\n");
 #endif
+	if (s2.__double[0] == 0 && s2.__double[1] == 0) {
+		return s1;
+	}
 	p = (char unsigned *) &s2;
 	*p ^= 0x80;	/* change sign of s2 */
 	s1 = adf8(s2,s1);	/* add and return result */