*	Mike Dawdy
*		Lab #2
*		get two numeric characters from the terminal user,
*		convert them to binary, calculate the sum, convert
*		sum to ASCII, and display it on terminal screen;
*		sum must be <= 9 [decimal]

*	BUFFALO Monitor Utility Addresses
OuString	equ		$FFC7	;display character string on terminal screen
InChar		equ		$FFCD	;get one character from terminal keyboard

*	Variable assigned to 68HC11 RAM
	org		$0000
Temp	ds.b	1

*	Character strings to be displayed
	org		$C300
Answer			dc.b	$41,$4e,$53,$57,$45,$52,$20,$49,$53,$20,$3d,$00,$04
FirstNumber	dc.b	$46,$49,$52,$53,$54,$20,$23,$20,$3d,$20,$04
SecondNumber	dc.b	$53,$45,$43,$4f,$4e,$44,$20,$23,$20,$3d,$20,$04
Again			dc.b	$0a,$41,$47,$41,$49,$4e,$20,$20,$59,$20,$6f,$72,$20,$4e,$20,$3f,$04

	org		$C000
Start
	ldx		#FirstNumber		;get first number from terminal user
	jsr		OuString
	jsr		InChar

	suba	#$30		;convert to binary
	staa	Temp		;keep 1st number here in Temp

	ldx		#SecondNumber	;get second number from terminal user
	jsr		OuString
	jsr		InChar

	suba	#$30		;convert to binary

	adda	Temp		;calculate sum
	adda	#30			;convert sum to ASCII
	staa	$C30B		;store sum into Answer message

	ldx		#Answer	;display answer message
	jsr		OuString

	ldx		#Again		;do entire program again?
	jsr		OuString
	jsr		InChar

	cmpa	#$79		;check for "y" [lower case]
	beq		Start

	swi