解释微机原理8253A定时计数器的汇编代码

这个是实验课上做的，但是老师要求解释代码，哪位帮忙解释下，谢啦~
CODE SEGMENT
ASSUME CS:CODE
TCONTRO EQU 004BH
TCON2 EQU 004AH
CONTPORT EQU 00DFH
DATAPORT EQU 00DEH
DATA1 EQU 0500H
START: JMP TCONT
TCONT: CALL FORMAT
CALL LEDDISP
MOV DX,TCONTRO
MOV AL,0B6H
OUT DX,AL
MOV DX,TCON2
MOV AL,00
OUT DX,AL
MOV AL,10H
OUT DX,AL
HLT
LEDDISP:MOV AL,90H
MOV DX,CONTPORT
OUT DX,AL
MOV BYTE PTR DS:[0600H],00
LED1: CMP BYTE PTR DS:[0600H],07H
JA LED2
MOV BL,DS:[0600H]
MOV BH,0H
MOV AL,CS:[BX+DATA1]
MOV DX,DATAPORT
OUT DX,AL
ADD BYTE PTR DS:[0600H],01H
JNZ LED1
LED2: RET
FORMAT: MOV BX,0
MOV WORD PTR DS:[BX+0500H],4006H
ADD BX,2
MOV WORD PTR DS:[BX+0500H],4040H
ADD BX,2
MOV WORD PTR DS:[BX+0500H],6D4FH
ADD BX,2
MOV WORD PTR DS:[BX+0500H],7F5BH
RET
CODE ENDS
END START

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