Nhap xuat Thap luc phan

.MODEL
.STACK
.DATA
    TBAO1 DB 13,10,"NHAP SO THAP LUC PHAN (TOI DA 4 KY SO) : $"
    TBAO2 DB 13,10,"XUAT SO THAP LUC PHAN : $"
    LOI DB 13,10,"BAN NHAP SAI$"
.CODE
   MOV AX,@DATA
   MOV DS,AX

   LEA DX,TBAO1
   MOV AH,9
   INT 21H

   XOR BX,BX
   MOV AH, 1
   MOV CL,4
   FOR1:
       INT 21H

       CMP AL, 0DH
       JE  END_FOR

       CMP AL, 30H
       JB NHAPSAI

       CMP AL,'9'
       JBE NUMBER

       CMP AL,'A'
       JB NHAPSAI

       CMP AL,'F'
       JBE LETTER

       JMP NHAPSAI

       NUMBER:
       SUB AL, 48
       JMP SHIFT

       LETTER:
           SUB AL, 37H
       SHIFT:
           SHL BX, 4
           OR BL, AL
           JMP LAP
       LAP:
           LOOP FOR1
           JMP END_FOR
       NHAPSAI:
           MOV AH,9
           LEA DX,LOI
           INT 21H
           JMP KETTHUC

   END_FOR:
       MOV AH,9
       LEA DX,TBAO2
       INT 21H
   PRINTN:
       MOV CX, 4
       MOV AH, 2

   FOR:
       MOV DL, BH
       SHR DL, 4

       CMP DL, 10
       JB NUM
       JAE LETTER2

       NUM:
       ADD DL , 48
       INT 21H
       JMP END_OF_LOOP2

       LETTER2:
       ADD DL , 55
       INT 21H


       END_OF_LOOP2:
       ROL BX,4
    LOOP FOR

   KETTHUC:
    MOV AH , 4CH
    INT 21H
END