339 lines
9.9 KiB
NASM
Executable File
339 lines
9.9 KiB
NASM
Executable File
DATA SEGMENT
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A8255A EQU 280H
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A8255B EQU 281H
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A8255C EQU 282H
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A8255COM EQU 283H
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A8254A EQU 288H
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A8254B EQU 289H
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A8254COM EQU 28BH
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OLD_OFF DW 0
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OLD_SEG DW 0
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TMP1 DB 0
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TMP2 DB 0
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LED DB 3FH, 06H, 5BH, 4FH, 66H, 6DH, 7DH, 07H, 7FH, 6FH, 77H, 7CH, 39H, 5EH, 79H, 71H
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WAITING DB 40H ; 等待状态的字节码
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FAULT DB 71H ; 违规状态的字节码
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SUCCESS DB 6DH ; 抢答成功状态的字节码
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ZERO DB 3FH ; 数码管显示0的字节码
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DATA ENDS
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CODE SEGMENT
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ASSUME DS:DATA, CS:CODE
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; 1. 程序逻辑
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; 1.1. 当K7为0时，K0-6都必须为0，否则为1的违规，数码管显示违规选手 && 扬声器鸣叫
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; 1.2. 当K7为1时，当K0-6中有一个为1时，停止检测，为1的按键对应的选手抢答成功，数码管显示抢答成功选手
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; 2. 程序设计
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; 2.1. 2个PROC
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; 2.1.1. PROC1扫描到 K7为0 && K0-6中存在1的按键时进入，K0-6全为0时退出
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; 进入PROC1后蜂鸣器响起，不断扫描K0-7，数码管显示违规选手。
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; 当全为0时蜂鸣器关闭，退出PROC1
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; 2.1.2. PROC2扫描到K7为1时进入，K7为0时退出
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; 进入PROC2后循环扫描K0-7，K0-6存在1后数码管显示抢答成功选手
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; 继续循环扫描，但只看K7，K7为0时退出
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; 进入PROC2后进行计时，4秒后若无变化，触发中断，退出PROC
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; 2.2. 主程序 循环扫描K0-7
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; 2.2.1. K7为0 && K0-6按键全0时不变，继续循环
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; 2.2.2. K7为0 && K0-6中存在1的按键时进入PROC1
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; 2.2.2. K7为1时进入PROC2
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START:
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MOV AX, DATA
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MOV DS, AX
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CLI ; 关中断，防止中断干扰
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; 保存旧的中断向量
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MOV AX, 350BH
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INT 21H
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MOV OLD_OFF, BX
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MOV BX, ES
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MOV OLD_SEG, BX
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; 设置新的中断向量
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MOV AX, 250BH
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MOV DX, SEG TIMEOUT
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MOV DS, DX
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MOV DX, OFFSET TIMEOUT
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INT 21H
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STI
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; 恢复数据段
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MOV AX, DATA
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MOV DS, AX
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; 初始化8255
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MOV AX, 10001001B ; A口输出段码，B口输出位码，C口输入拨动开关
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MOV DX, A8255COM
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OUT DX, AL
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; 使用8254 A口将1MHz降频为1kHz，为8254 B口提供时钟源
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MOV DX, A8254COM
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MOV AL, 00110110B
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OUT DX, AL
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MOV DX, A8254A
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MOV AL, 11101000B
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OUT DX, AL
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MOV AL, 00000011B
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OUT DX, AL
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; 主程序
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MAIN:
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MOV DX, A8255C
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IN AL, DX
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MOV SI, 0 ; 中断标志位
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; K7为0 && K0-6按键全0时不变，继续循环
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CMP AL, 0 ; 比较AL寄存器的值与0
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JE MAIN ; 如果相等，则跳转到MAIN
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; K7为0 && K0-6中存在1的按键时进入PROC1
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AND AL, 10000000B ; 将AL寄存器的值与10000000B进行按位与操作
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CMP AL, 0 ; 比较AL寄存器的值与0，即判断第7位是否为0
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JNE P2 ; 如果不相等，则跳转到P2
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CALL PROC1 ; 调用PROC1子程序
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; K7为1时进入PROC2
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P2:
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CALL PROC2 ; 调用PROC2子程序
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JMP MAIN ; 无条件跳转到MAIN
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FINISH:
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CLI ; 关中断，防止中断干扰
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MOV AX, 250BH ; 恢复原来的中断向量
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MOV DX, OLD_OFF
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MOV DS, DX
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MOV DS, OLD_SEG
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INT 21H
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MOV AX, 4C00H
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INT 21H
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PROC1 PROC NEAR
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; K7为0 && K0-6中存在1的按键时进入，K0-6全为0时退出
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; 进入PROC1后蜂鸣器响起，不断扫描K0-7，数码管显示违规选手。
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; 当全为0时，蜂鸣器关闭，退出PROC1
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PUSH DX
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PUSH CX
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LOOP1:
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MOV DX, A8255C
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IN AL, DX
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MOV TMP1, AL
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CMP AL, 0
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JE RETURN1
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MOV CX, 8
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MOV TMP2, 10000000B ; 位码
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LOOP2:
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ROR TMP2, 1
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JMP OUTPUT1
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BACK1:
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LOOP LOOP2
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JMP LOOP1
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; 在数码管上输出
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OUTPUT1:
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CALL CLEAR
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MOV AL, TMP1
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AND AL, TMP2
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CMP AL, TMP2
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JE FAULT1
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MOV AL, WAITING
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JMP DISPLAY1
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FAULT1:
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MOV AL, FAULT
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DISPLAY1:
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MOV DX, A8255A
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OUT DX, AL
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MOV DX, A8255B
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MOV AL, TMP2
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OUT DX, AL
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CALL DELAY
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JMP BACK1
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RETURN1:
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CALL CLEAR
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POP CX
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POP DX
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RET
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PROC1 ENDP
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PROC2 PROC NEAR
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; 进入PROC2后循环扫描K0-7，K0-6存在1后数码管显示抢答成功选手
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; 继续循环扫描，但只看K7，K7为0时退出PROC2
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PUSH DX
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PUSH CX
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MOV SI, 0 ; 时间到退出抢答标志
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; 开始计时，1000Hz * 4000 = 4s后输出低电平，取反后用于触发中断
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MOV DX, A8254COM
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MOV AL, 10111000B
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OUT DX, AL
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MOV DX, A8254B
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MOV AL, 10100000B
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OUT DX, AL
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MOV AL, 00001111B
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OUT DX, AL
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; 设置中断屏蔽
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CLI
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IN AL, 21H
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AND AL, 11110111B
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OUT 21H, AL
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STI
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LOOP3:
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CMP SI, 1
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JE RETURN2
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MOV DX, A8255C
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IN AL, DX
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MOV TMP1, AL
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AND AL, 10000000B ; 位码
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CMP AL, 0
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JE RETURN2
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MOV AL, TMP1
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AND AL, 01111111B
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MOV TMP1, AL
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CMP AL, 0
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JE LOOP3
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; 检测到有变化，恢复中断屏蔽，取消中断
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CLI
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IN AL, 21H
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OR AL, 00001000B
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OUT 21H, AL
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STI
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LOOP4:
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MOV DX, A8255C
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IN AL, DX
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AND AL, 10000000B
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CMP AL, 0
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JE RETURN2
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MOV CX, 7
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MOV TMP2, 10000000B ; 位码
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LOOP5:
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ROR TMP2, 1
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JMP OUTPUT2
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BACK2:
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LOOP LOOP5
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JMP LOOP4
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OUTPUT2:
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CALL CLEAR
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MOV AL, TMP1
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AND AL, TMP2
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CMP AL, TMP2
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JE SUCCESS2
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MOV AL, WAITING
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JMP DISPLAY2
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SUCCESS2:
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MOV AL, SUCCESS
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DISPLAY2:
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MOV DX, A8255A
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OUT DX, AL
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MOV DX, A8255B
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MOV AL, TMP2
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OUT DX, AL
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CALL DELAY
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JMP BACK2
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RETURN2:
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CALL CLEAR
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; 恢复中断屏蔽
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CLI
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IN AL, 21H
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OR AL, 00001000B
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OUT 21H, AL
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STI
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POP CX
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POP DX
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RET
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PROC2 ENDP
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TIMEOUT PROC FAR
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CLI
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PUSH CX
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PUSH BX
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MOV SI, 1
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CALL CLEAR
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MOV BX, 0FH
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LOOP6:
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MOV CX, 8
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MOV TMP1, 00000001B ; 位码
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LOOP7:
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ROR TMP1, 1
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JMP OUTPUT3
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BACK3:
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LOOP LOOP7
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DEC BX
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JZ RETURN3
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JMP LOOP6
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OUTPUT3:
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MOV AL, ZERO
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MOV DX, A8255A
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OUT DX, AL
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MOV DX, A8255B
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MOV AL, TMP1
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OUT DX, AL
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CALL DELAY
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JMP BACK3
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RETURN3:
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MOV AL, 20H ; 发送EOI指令
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OUT 20H, AL
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POP BX
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POP CX
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STI
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IRET
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TIMEOUT ENDP
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CLEAR PROC NEAR
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PUSH DX
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PUSH AX
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MOV DX, A8255A
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MOV AL, 00000000B
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OUT DX, AL
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MOV DX, A8255B
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MOV AL, 0
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OUT DX, AL
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POP AX
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POP DX
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RET
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CLEAR ENDP
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DELAY PROC NEAR
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PUSH CX
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PUSH BX
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MOV CX, 0FFFFH
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LOOP8:
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MOV BX, 2
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LOOP9:
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DEC BX
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JNZ LOOP9
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DEC CX
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JNZ LOOP8
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POP BX
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POP CX
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RET
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DELAY ENDP
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END START
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CODE ENDS |