bin:	ld	b,0		; ANSWER := 0;
binloop:call	get		; A := INPUT [character];
	cp	'0'		; is A LT '0'?
	ret	c		; if so then return;
	cp	'2'		; is A LT '2'?
	ret	nc		; if not then return;
	rra			; CARRY := A0;
	ld	a,b		; A := ANSWER;
	rla			; rotate carry into A;
	ret	c		; overflow: if CARRY = 1 then return;
	ld	b,a		; ANSWER := A;
	jp	binloop		; reiterate for next bit;