decback macro				;converts ascii to decimal

					;A0 = Source, must end with an
					;     illegal char. eg 0

					;D0 = Answer
	moveq #0,d0
	moveq #0,d1
.\@hloop
	move.b (a0)+,d1
	sub.b #"0",d1
	cmp.b #10,d1
	bcc .\@decinok
	mulu #10,d0
	add.b d1,d0
	bra .\@hloop
.\@decinok

	endm