L3:     PUSH ACC
        PUSH PSW
        MOV TL0,#18H
        MOV TH0,#0FDH
        JB 20H.0,H1
        MOV A,61H
        CLR P2.4
        MOV DPTR,#TAB
        MOVC A,@A+DPTR
        MOV P0,A
        SETB 20H.0
        LJMP H4
H1:    JB 20H.1,H2
       MOV A,62H
       CLR P2.5
       MOV DPTR,#TAB
       MOVC A,@A+DPTR
       MOV P0,A
       SETB 20H.1
       LJMP H4
H2:    JB 20H.2,H3
       MOV A,63H
       CLR P2.6
       MOV DPTR,#TAB
       MOVC A,@A+DPTR
       MOV P0,A
       SETB 20H.2
       AJMP H4
H3:    JB 20H.3,H4
       MOV A,64H
       CLR P2.7
       MOV DPTR,#TAB
       MOVC A,@A+DPTR
       MOV P0,A
       SETB 20H.3
H4:    POP PSW
       POP ACC
       RETI
TAB:DB 0C0H,0F9H,0A4H,0B0H,99H,92H,82H,0F8H,80H,90H