ORG	$6000		; Subroutine version of STRLEN
	LEA.L	DATA,A1		; get address of string
	BSR	STRLEN		; call strlen subroutine
	TRAP	#9		; done, go back to monitor
STRLEN	MOVEM.L	A1,-(A7)	; save original contents
	CLR.L	D0		; init count to 0
LOOP	CMPI.B	#0,(A1)+	; is it the NULL char?
	BEQ	DONE		; if yes, we are done
	ADDQ.W	#1,D0		; else add 1 to count
	BRA	LOOP		; repeat for next char
DONE	MOVEM.L	(A7)+,A1	; restore oringal contents
	RTS			; ReTurn from Subroutine
DATA	DC.B	'alabama and tennessee'
	DC.B	0		; here DATA is after code
	END