ORG 1000H SDOMUL: MOV R0,#20H MOV A,@R0 ANL A,#80H MOV R3,A JZ L1 ACALL L0 L1: INC R0 INC R0 MOV A,@R0 ANL A,#80H MOV R2,A JZ L2 ACALL L0 L2: MOV A,R3 XRL A,R2 MOV 08H,A MOV R2,#4 MOV R0,#20H MOV R1,#07H L3: MOV A,@R0 MOV @R1,A INC R0 DEC R1 DJNZ R2,L3 MOV R0,#30H LCALL START MOV A,80H JNZ L4 SJMP L6 L4: CLR C MOV R0,#30H MOV R3,#3 MOV A,@R0 CPL A ADD A,#1 MOV @R0,A L5: INC R0 MOV A,@R0 CPL A ADDC A,#0 MOV @R0,A DJNZ R3,L5 L6: RET L0: CLR C INC R0 MOV A,@R0 CPL A ADD A,#1 MOV @R0,A DEC R0 MOV A,@R0 CPL A ADDC A,#0 MOV @R0,A RET