ORG	$7510
THERM	DC.L	0		; reserve and clear space for temperature
	ORG	$7520
LENNOX	DC.L	0		; reserve and clear space for on/off
	ORG	$6000
START	MOVE.B	#78,D1		; put 78 degrees as thermostat setting
	MOVE.B	#85,THERM	; put 85 degrees as current temperature
	MOVE.L	#50,D7		; set the loop counter
TLOOP	BSR	AIRCTRL
	BSR	STATUS		; show status
	BSR	DELAY1		; wait for a little time
	TST.B	LENNOX		; nudge temperature depending on AC status
	BNE	COOLIT
	ADDI.B	#1,THERM	; increase by 1 degree
	BRA	NEXT
COOLIT	SUBI.B	#1,THERM	; decrease by 1 degree
NEXT	SUBQ.W	#1,D7
	BGT	TLOOP		; loop a bunch of times
	TRAP	#9

	ORG	$6100
AIRCTRL	MOVEM.L	D0/D1,-(A7)	; AIRCTRL is main thermostat function
	MOVE.B	THERM,D0	; get current temperature
	ADDQ.B	#2,D1		; convert setting to upper limit
	CMP.B	D1,D0		; too hot?
	BGE	TURNON		; turn unit on
	SUBQ.B	#4,D1		; convert setting to lower limit
	CMP.B	D1,D0		; too cold?
	BLE	TURNOFF		; turn unit off
	BRA	AIRDONE
TURNON	MOVE.B	#1,LENNOX	; set on/off port to on
	BRA	AIRDONE
TURNOFF	MOVE.B	#0,LENNOX	; set on/off port to off
AIRDONE	MOVEM.L	(A7)+,D0/D1
	RTS

	ORG	$6200
STATUS	MOVEM.L	D0/A3,-(A7)	; STATUS prints temperature and AC on or off
	LEA.L	MSGTEMP,A3	; set a3 to display "temperature"
	TRAP	#3		; print it
	CLR.L	D0		; clear upper bytes
	MOVE.B	TEMP,D0		; get temperature as byte
	BSR	TOSTR		; print the temperature
	MOVE.B	LENNOX,D0	; get the air conditioner status
	BEQ	SAYOFF		; is it off?
	LEA.L	MSGON,A3	; set a3 to display "air is on"
	TRAP	#3
	MOVEM.L	(A7)+,D0/A3
	RTS
SAYOFF	LEA.L	MSGOFF,A3
	TRAP	#3
	MOVEM.L	(A7)+,D0/A3
	RTS
	ORG	$6300
MSGTEMP	DC.B	'  temperature is '
	DC.B	0
MSGON	DC.B	'  airconditioner is on'
	DC.B	13,0
MSGOFF	DC.B	'  airconditioner is off'
	DC.B	13,0,0

	ORG	$6400
DELAY1	MOVEM.L	D0-D2,-(A7)	; DELAY1 should use up a second of time
	MOVE.L	#30000,D0	; choose to get 1 second, but depends on PC speed
DLOOP	MOVE.L	#455,D1		; do some arbitrary divide to eat up time
	MOVE.L	#39,D2
	DIVS	D2,D1
	SUB.L	#1,D0
	BGT	DLOOP
	MOVEM.L	(A7)+,D0-D2
	RTS

	ORG	$7000
TOSTR	MOVEM.L	D0/A3,-(A7)	; TOSTR prints value in D0 as text
	LEA.L	SDATA,A3
SLOOP	TST.L	D0		; while not zero
	BEQ	SDONE
	DIVU	#10,D0		; next decimal character
	SWAP	D0		; get remainder
	ADDI.B	#'0',D0		; make it ascii
	MOVE.B	D0,-(A3)	; output to string
	CLR.B	D0		; zero out the remainder
	SWAP	D0		; restore value
	BRA	SLOOP
SDONE	TRAP	#3
	MOVEM.L	(A7)+,D0/A3
	RTS
	DS.B	8		; space for tostr output
SDATA	DC.B	13		; newline at end
	DC.B	0		; null termination
	END