SBCDM:
MOV R0,#20H
MOV A,@R0
MOV R1,A
MOV R7,#03H
CLR A
MOV @R0,A
LOOP0:
MOV R0,#20H
XCHD A,@R0
MOV R4,A
MOV A,@R0
RR A
RR A
RR A
RR A
MOV @R0,A
INC R0
MOV A,R4
XCHD A,@R0
MOV R2,A
MOV A,@R0
RR A
RR A
RR A
RR A
MOV @R0,A
MOV A,R2
JZ A,LOOP3
DEC R0
MOV A,@R0
MOV R3,#00h
LOOP1:
CLR C
ADD A,R1
DA A
JNC LOOP2
INC R3
LOOP2:
DJNZ R2,LOOP1
MOV @R0,A
MOV A,R3
LOOP3:
DJNZ R7,LOOP0
RET