small to capital assembly language

.MODEL SMALL
.STACK 100H
.DATA
MSG1 DW "SMALL LETTER- $"
MSG2 DW "CAPITAL LETTER- $"

.CODE
MAIN PROC

   MOV AX,@DATA
   MOV DS,AX

   ;MSG1
   LEA DX,MSG1
   MOV AH,9
   INT 21H

   ;SCAN
   MOV AH,1
   INT 21H
   MOV BL,AL
   SUB BL,32

   ;NEW LINE
   MOV AH,2
   MOV DL,0DH
   INT 21H
   MOV DL,0AH
   INT 21H

   ;MSG2
   LEA DX,MSG2
   MOV AH,9
   INT 21H

   ;PRINT
   MOV AH,2
   MOV DL,BL
   INT 21H

   MAIN ENDP
END MAIN