Question

Assembly code

Write an assembly program that converts all uppercase letters to their corresponding lower cases. meanwhile all characters that are not upper case letters should remain unchanged.

Hint: ASCII: a = 97, z = 122, A = 65, Z = 90

String : "Riders On The Storm - The Doors"

Answer 1

.MODEL SMALL
        .DATA

                MSG  DB  0DH,0AH, \' ENTER THE STRING :-----> :  $\'
                MSG2 DB  0DH,0AH, \' YOUR STRING IS  :-----> :  $\'
                STR1 DB  255 DUP(?)
                ONE  DB ?
                TWO  DB ?
          .CODE

BEGIN:
          MOV AX,@DATA
          MOV DS,AX

          LEA DX,MSG
          MOV AH,09H
          INT 21H

          LEA SI,STR1
          MOV AH,01H

READ:
          INT 21H
          MOV BL,AL

          CMP AL,0DH
          JE  DISPLAY

          XOR AL,20H
          MOV [SI],AL
          INC SI

          ;CMP BL,0DH
          JMP READ



DISPLAY:

          MOV AL,\'$\'
          MOV [SI],AL

          LEA DX,MSG2
          MOV AH,09H
          INT 21H


          LEA DX,STR1
          MOV AH,09H
          INT 21H



         ; MOV AH,4CH
         ; INT 21H
          .EXIT



END BEGIN