阅读下面程序段，指出它的功能。 DATA SEGMENT ASCII DB 30H, 31H, 32H, 33H ,34H ,35H, 36H, 37H, 38H, 39H HEX DB 04H DATA ENDS CODE SEGMENT ASSUME CS:CODE, DS: DATA START: MOV AX, DATA MOV DS, AX MOV BX,OFFSET ASCII MOV AL,HEX AND AL,0FH MOV AH,0 ADD BX,AX MOV AL,[BX] MOV DL,AL MOV AH,2 INT 21H MOV AH,4CH INT 21H CODE ENDS END START