za4.asm

小键盘与数码管 利用小键盘输入数字

        DATA  SEGMENT
       ADINT  DB        'THIS IS A 8259A INTERRUPT!',0AH,0DH,'$'
       DATA1  DB        0
        DATA  ENDS
        CODE  SEGMENT
              ASSUME    CS:CODE,DS:DATA
      START:
              MOV       AX,SEG INT2
              MOV       DS,AX
              MOV       DX,OFFSET INT2
              MOV       AX,350BH
              INT       21H         ;置中断向量表
              PUSH      ES
              PUSH      BX          ;保存中断向量
              PUSH      DX
              MOV       AX,250BH
              INT       21H         ;设置新中断向量
              POP       DS
              CLI                   ;关中断
              IN        AL,21H      ;读中断屏蔽寄存器
              AND       AL,0F7H
              OUT       21H,AL      ;允许IRQ2中断
              STI
              MOV       AX,SEG DATA1
              MOV       DS,AX
      LOOP2:  MOV       AL,DATA1
              CMP       AL,10
              JB        LOOP2
              CLI
              IN        AL,21H
              OR        AL,08H      ;屏蔽IRQ2中断
              OUT       21H,AL
              STI
              MOV       AL,0
              MOV       AH,4CH
              INT       21H
       INT2:  PUSH      AX          ;中断处理程序
              PUSH      DS
              PUSH      DX
              STI
              MOV       AX,DATA
              MOV       DS,AX
              MOV       DX,OFFSET ADINT
              MOV       AH,09
              INT       21H
              MOV       AL,20H
              OUT       20H,AL
              INC       BYTE PTR DATA1
              POP       DX
              POP       DS
              POP       AX
              IRET
        CODE  ENDS
              END       START