47 lines
1.2 KiB
NASM
Executable File
47 lines
1.2 KiB
NASM
Executable File
DATA SEGMENT
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T DW 0FFH
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DATA ENDS
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CODE SEGMENT
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ASSUME CS:CODE, DS:DATA
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START:
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MOV AX, DATA
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MOV DS, AX
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MOV DX, 283H ; 命令口
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MOV AL, 10010000B ; 1|00(A组0方式)|1(PA输入)|0(PC4-7输出)|0(B组0方式)|0(PB输出)|0(PC0-3输出)
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OUT DX, AL
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MOV DX, 281H ; B口
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MOV AL, 00H ; LED全置0
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OUT DX, AL
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MOV DX, 280H ; A口
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IN AL, DX ; 读入到AL
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MOV DX, 281H ; B口
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LP:
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OUT DX, AL ; 从B口输出AL
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CALL DELAY ; 延时
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ROR AL, 1 ; ROR(Rotate Right)把AL向右移1位，移出的位补到左边，实现走马灯
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JMP LP ; 无限循环
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DELAY PROC
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PUSH BX
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PUSH AX
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MOV BX, T
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MOV AX, T
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DL1:
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DL2:
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DEC BX
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JNZ DL1
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DEC AX
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JNZ DL2
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POP AX
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POP BX
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RET
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DELAY ENDP
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CODE ENDS
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END START |