A.XCHG AX,DI B.XCHG BX,[SI+3] C.XCHG AL,20H D.XCHG NUM,DX
A.MOV AX,1234H B.MOV BX,[1234H] C.MOV DS,AX D.MOV 2000H,AX
A.直接尋址 B.立即尋址 C.寄存器尋址 D.寄存器間接尋址