DV31: CLR C MOV A,R3 SUBB A,R7 JC DV30 SETB OV RET DV30: MOV R2,#10H DM23: CLR C MOV A,R5 RLC A MOV R5,A MOV A,R4 RLC A MOV R4,A MOV A,R3 RLC A MOV R3,A MOV F0,C CLR C SUBB A,R7 ANL C,/F0 JC DM24 MOV R3,A INC R5 DM24: DJNZ R2,DM23 MOV A,R3 ADD A,R3 JC DM25 SUBB A,R7 JC DM26 DM25: INC R5 MOV A,R5 JNZ DM26 INC R4 DM26: CLR OV RET