123.asm

这是一个利用汇编语言编写的存储器扩展实验的应用

                       DATA SEGMENT
            OK DB 'THIS IS A 8259A INTERRUPT',0AH,0DH,'$'
            OCW1 DB ?
            DATA ENDS
            CODE SEGMENT
            ASSUME CS:CODE,DS:DATA

            START:MOV AX,DATA
                  MOV DS,AX
                  CLI
                  MOV AX,350FH
                  INT 21H
                  PUSH BX
                  PUSH ES
                  PUSH DS
                  MOV AH,40H
                  MOV CX,0510H
                  MOV DX,2065H
                  MOV BH,07H
                  MOV AL,1
                  INT 10H
                  MOV AX,SEG FUWU
                  MOV DS,AX
                  MOV DX,OFFSET FUWU
                  MOV AX,250FH
                  INT 21H
                  POP DS
                  IN AL,21H
                  MOV OCW1,AL
                  AND AL,7FH
                  OUT 21H,AL
                   MOV BX,10
                  STI
            NEXT:
                 JZ NEXT
                 MOV AL,OCW1
                 OR AL,80H
                 OUT 21H,AL
                 POP DS
                 POP DX
                 MOV AX,250FH
                 INT 21H
                 MOV AH,4CH
                 INT 21H

            FUWU PROC FAR
                 PUSH AX
                 PUSH BX
                 PUSH DS
                 PUSH DX
                 STI
                 MOV AX,DATA
                 MOV DS,AX

                 MOV DX,OFFSET OK
                 MOV AH,9
                 INT 21H
                 INC DH
                 MOV AL,20H
                 OUT 20H,AL
                 POP DX
                 POP DS
                 POP BX
                 POP AX
                 IRET
            FUWU ENDP
            CODE ENDS
                 END START