sy8-8251.asm

汇编语言接口技术硬件实验中

        DATA  SEGMENT
        MESS  DB        'Please enter a charater:',0DH,0AH,'$'
        DATA  ENDS

        CODE  SEGMENT
              ASSUME    CS:CODE,DS:DATA
      START:
              MOV       BX,DATA
              MOV       DS,BX

              MOV       DX,0C403H
              MOV       AL,00010110B
              OUT       DX,AL
              MOV       DX,0C400H
              MOV       AL,34H
              OUT       DX,AL

              MOV       CX,03H
      LOOP1:  MOV       DX,0C439H
              MOV       AL,0
              OUT       DX,AL
              NOP
              NOP
              NOP
              NOP
              NOP
              LOOP      LOOP1

              MOV       DX,0C439H
              MOV       AL,01000000B
              OUT       DX,AL

              MOV       AL,11001110B
              OUT       DX,AL

              MOV       AL,00110111B
              OUT       DX,AL

              LEA       DX,MESS
              MOV       AH,09H
              INT       21H

         L0:  MOV       DX,0C439H
         L1:  IN        AL,DX

              TEST      AL,01H
              JZ        L1

              MOV       AH,01H
              INT       21H

              CMP       AL,1BH
              JZ        ENDD

              ADD       AL,1
              MOV       DX,0C438H
              OUT       DX,AL
              NOP
              NOP
              NOP
              NOP

              ;IN        AL,DX
              ;MOV       DL,AL
              ;MOV       AH,02H
              ;INT       21H

              MOV       DX,0C439H
         L2:  IN        AL,DX
	 
              TEST      AL,02H
              JZ        L2

              MOV       DX,0C438H
              IN        AL,DX

              MOV       DL,AL
              MOV       AH,02H
              INT       21H

              JMP       L0
       ENDD:
              MOV       AH,4CH
              INT       21H
        CODE  ENDS
              END       START