MCS-51单片机应用子程序：1.5.2 双字节开方

DUSQR: MOV R2,#00H LP: MOV A,R2 ADD A, R2 MOV R7, #00H XCH A, R7 ADDC A, #00H XCH A, R7 ADD A, #01H XCH A, R7 ADDC A, #00H XCH A, R7 MOV R6, A CLR C MOV A, R5 SUBB A, R6 MOV R5, A MOV A, R4 SUBB A, R7 MOV R4, A JC RETURN INC R2 SJMP LP RETURN: RET