title: How to convert the uppercase to lowercase character in assembly language 8086
body: <p>Mam/Sir Somebody can help me!!!!</p>
  
  <p>I did the format that displayed of the horizontal position after input the single character and so that is a requirement of the output</p>
  
  <p>So this is a expected output</p>
  
  <p>The output should be like this:
  EVEN EVEN</p>
  
  <p>Input: X</p>
  
  <p>xyz</p>
  
  <p>The requirement should be one input character, first problem is, i didn't not displayed of the lowercase letter when you inputting the uppercase letter, and the last problem is validation instead of the typing the single lowercase it converts to displayed of the uppercase, The validation it should be type the uppercase and it converts to displayed the lowercase, when you type the single lowercase letter it should be not displayed the output this is one of the problem!!!!</p>
  
  <p>Here is my code</p>
  
  <pre><code>.model small
  .stack
  .data
      input db "Input: $"
  .code
  org 100h
  
  start:
  
      main proc
  
          mov ax,03
          int 10h
  
          mov ax,@data
          mov ds,ax   
  
          mov ah,9     
          lea dx, input
          int 21h
  
          mov ah,01
          int 21h
  
          mov dh,al
                  mov ah,02
                  mov dl,9
                  int 21h
                  mov dl,13
                  int 21h
  
          mov cx,11
          W:
              mov dl,10
              int 21h
              LOOP W
  
          mov al,dh
  
          mov bl,al
  
          cmp bl, 'a'
          jb main
          cmp bl, 'z'
          ja main
  
          mov dl,al
          sub dl,20h
  
          mov ah,02
          int 21h
  
          mov cx,26
          mov dh,dl
  
              letters:
  
                   mov bx,cx
  
                   mov dl,dh
  
                   cmp dl,'Z'
                   je exit
  
                   inc dl
                   int 21h
                   mov dh,dl
                   mov cx,bx
  
              loop letters
  
  
  
          mov ah,4ch
          int 21h
      main endp
  
      down proc
                  mov dl,13
                  int 21h
                  mov dl,10
                  int 21h
                  ret
              down endp
  
              exit proc
  
          mov cx,12
          Q:
              call down
              LOOP Q
              mov ah, 9
  
                  mov ah,4ch
                  int 21h
              exit endp
  
  end start
  </code></pre>