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JMP $2
TIMER0:

PUSH PSW
PUSH A
PUSH B
PUSH DPH
PUSH DPL
MOV TH0,#>(65536-5000)
MOV TL0,#<(65536-5000)
CALL DISPLAY
CALL CHECK_KEY
CALL CHANGE_DISPLAY
POP DPL
POP DPH
POP B
POP A
POP PSW
RETI
TAKE_DISPLAYCODE:
INC A
MOVC A,@A+PC
RET
DB C0H,F9H,A4H,B0H
DB 99H,92H,82H,F8H
DB 80H,90H,88H,83H
DB C6H,A1H,86H,8EH
SHIFT_BUFFER:
MOV A,KEYBUF0
MOV R0,#BUFFER
MOV R1,#04H
$1:
XCH A,@R0
INC R0
DJNZ R1,$1
RET
DISPLAY:
MOV P0,#00H
MOV A,COUNTER
ORL A,#01111000B