单片机汇编语言实现20秒倒计时程序，要求用动态显示，跪求大神！！！！！

ORG   0000H
JMP   BEGIN
ORG	000BH
LJMP	T0INT
ORG	001BH
LJMP	T1INT
LEDD	EQU	30H
LEDC	EQU 36H
SECC	EQU 37H
TCNT	EQU 3AH
ORG 0030H
;---------------------------------------
TABLE:      ; 共阴极数码管显示代码表
DB 0FCH	;"0"	00H
DB 60H	;"1"	01H
DB 0DAH	;"2"	02H
DB 0F2H	;"3"	03H
DB 66H	;"4"	04H
DB 0B6H	;"5"	05H
DB 0BEH	;"6"	06H
DB 0E0H	;"7"	07H
DB 0FEH	;"8"	08H
DB 0F6H	;"9"	09H
DB 0EEH	;"A"	0AH
DB 3EH	;"B"	0BH
DB 9CH	;"C"	0CH
DB 7AH	;"D"	0DH
DB 9EH	;"E"	0EH
DB 8EH	;"F"	0FH
DB 00H	;" "	10H
;          DB    3FH,06H,5BH,4FH,66H ;12345
;          DB    6DH,7DH,07H,7FH,     ;6789
;---------------------------------------
DELAY:  
MOV   R6,#25
DLY01:  
MOV   R7,#100
DJNZ  R7,$
DJNZ  R6,DLY01
RET
;---------------------------------------
BEGIN:  
MOV SP,#5FH
MOV TMOD,#11H
MOV TH0,#3CH
MOV TL0,#0B0H
MOV TH1,#0F4H
MOV TL1,#48H
MOV LEDC,#6
MOV R0,#LEDD
CLR A
INIT:
MOV @R0,A
INC R0
DJNZ LEDC,INIT
SETB ET1
SETB TR1
MOV P2,#0
MOV TCNT,#0
MOV SECC,#0
SETB ET0
SETB EA
MOV SECC,#20
LCALL DISSEC
SETB TR0
SETB TR1
LOOP:
SJMP $
;---------------------------------------
T1INT:
PUSH ACC
CLR TR1
MOV TH1,#0F4H
MOV TL1,#48H
SETB TR1
MOV DPTR,#TABLE
MOV R0,#LEDD
MOV A,LEDC
T1INT0:
JNZ T1INT1
MOV P2,#01H
MOV A,@R0
MOVC A,@A+DPTR
CPL A
MOV P0,A
SJMP T1INTD
T1INT1:
MOV P2,#02H
INC R0
MOV A,@R0
MOVC A,@A+DPTR
CPL A
MOV P0,A
T1INTD:
INC LEDC
MOV A,LEDC
CJNE A,#2,T1INT6
T1INT6:
JC T1INTE
MOV LEDC,#0
T1INTE:
POP ACC
RETI
;---------------------------------------
HBCD:
MOV B,#10
DIV AB 
SWAP A 
ORL A,B
RET 
;---------------------------------------
T0INT:
PUSH ACC
CLR TR0
MOV TH0,#3CH
MOV TL0,#0B0H
SETB TR0
INC TCNT
MOV A,TCNT
CJNE A,#20,T0INT1
T0INT1:
JC T0INTE
MOV TCNT,#0
MOV A,SECC
DEC A
MOV SECC,A
JNZ T0INT2
MOV SECC,#60
T0INT2:
LCALL DISSEC
T0INTE:
POP ACC
RETI
;---------------------------------------
DISSEC:
MOV A,SECC
LCALL HBCD
PUSH ACC
ANL A,#0FH
MOV 30H,A
POP ACC
SWAP A
ANL A,#0FH
MOV 31H,A
RET
;---------------------------------------
END