chengxu_01_05_02.asm

响铃程序（从键盘接收输入字符

DATAS SEGMENT 
     
    MESSAGE DB 'PLEASE INPUT A NUMBER TO RING$'   
DATAS ENDS 

STACKS SEGMENT 
    STACKS ENDS 

CODES SEGMENT 
    ASSUME CS:CODES,DS:DATAS,SS:STACKS 
START: 
    MOV AX,DATAS 
    MOV DS,AX 
    PRINT:  MOV AL,9 
        LEA DX,MESSAGE 
        INT 21 
         
        MOV AH,01H   
        INT 21H 
         
        CMP AL,3AH   
        JGE PRINT        
          
         CMP AL,30H       
        JL PRINT       
         
        MOV CX,0000H 
        AND AX,00FFH 
        MOV CL,AL 
        SUB CX,30H 
        MOV DL,01H 
AGAIN:  MOV AH,02H 
        INT 21H 
        LOOP AGAIN 
     
     
    MOV AH,4CH 
    INT 21H 
CODES ENDS 
    END START