DATAS SEGMENT
STR   DB 'Please input a character:$'
DAT1  DB ?
DAT2  DB ?
DAT3  DB ?
DAT4  DB ?
DAT5  DB ?
BUF1  DB 0AH,0DH,'IS A ALPHA$'
BUF2  DB 0AH,0DH,'IS A DIGITAL$'
BUF3  DB 0AH,0DH,'OTHER$'
BUF4  DB 0AH,0DH,'IT IS A SMALL LETTER$'
      DATAS ENDS

STACKS SEGMENT
       DB 200 DUP(?)
STACKS ENDS

CODES SEGMENT
    ASSUME CS:CODES,DS:DATAS,SS:STACKS
START:
       MOV AX,DATAS
       MOV DS,AX
      
       LEA DX,STR
       MOV AH,9
       INT 21H
      
    
       MOV AH,1
       INT 21H
      
       MOV DAT1,AL
       CMP AL,'0'
       JB  NEXT2
       CMP AL,'9'
       JNA NEXT1
      
       CMP AL,'A'
       JB  NEXT2
       CMP AL,'Z'
       JNA NEXT3
      
 
       CMP AL,'a'
       JB  NEXT2
       CMP AL,'z'
       JA  NEXT2
      
       SUB AL,20H
       MOV DAT2,AL
       MOV DL,0AH
       MOV AH,2
       INT 21H
       MOV DL,0DH
       MOV AH,2
       INT 21H
      
       MOV AL,DAT2
       MOV DL,AL
       MOV AH,2
       INT 21H
       LEA DX,BUF1
       MOV AH,9
       INT 21H
  
EXIT: MOV AH,4CH
       INT 21H

NEXT1: MOV DAT3,AL
       LEA DX,BUF2
       MOV AH,9
       INT 21H
       JMP EXIT

NEXT2: MOV DAT4,AL
       LEA DX,BUF3
       MOV AH,9
       INT 21H
       JMP EXIT

NEXT3: ADD AL,20H
       MOV DAT5,AL
      
       MOV AL,0AH
       MOV DL,AL
       MOV AH,2
       INT 21H
      
       MOV AL,0DH
       MOV DL,AL
       MOV AH,2
       INT 21H
      
       MOV AL,DAT5
       MOV DL,AL
       MOV AH,2
       INT 21H
      
       LEA DX,BUF4
       MOV AH,9
       INT 21H
       JMP EXIT       
  

CODES ENDS
    END START