MOV A,R6 CPL ACC.7 MOV R6,A JC DAB2 NSUB: MOV A,R4 SUB A,R7 MOV R4,A MOV A,R3 SUBB A,R6 MOV R3,A MOV A,R3 JB ACC.7,DABE DAB1: MOV C,SR0 MOV ACC.7,C MOV R3,A CLR OV RET DABE: SETB OV RET DAB2: LCALL NSUB MOV A,R3 JNB ACC.7,DAB1 LCALL CMPT CPL SR0 SJMP DAB1 RET