怎么读懂这个程序A8254 EQU 06C0HB8254 EQU 06C2HC8254 EQU 06C4HCON8254 EQU 06C6HSSTACK   SEGMENT STACK                 DW 32 DUP(?)SSTACK   ENDSCODE  SEGMENT ASSUME CS:CODESTART: MOV DX,CON8254 MOV AL, 36H OUT DX, AL MOV DX, A8254 MOV AL, OE8H OUT DX, AL MOV AL, 03H OUT DX, ALAA1:JMP AA1CODE   ENDS     END START