Microprocessor 8086 assembly-First and last character to uppercase

Microprocessor 8086 assembly-First and last character to uppercase

MODEL SMALL
.STACK 100H
.DATA
MSG1 DB "ENTER THE STRING :$"
MSG2 DB 0AH,0DH,"THE RESULT IS :$"
STRING DB 50 DUP('$')
.CODE
MAIN PROC
MOV AX,@DATA
MOV DS,AX

LEA DX,MSG1
CALL MESSAGE

LEA SI,STRING

LOOP1:
CALL INPUT
MOV BL,AL
MOV [SI],BL
CMP BL,0DH
JZ DOWN1
INC SI
JNE LOOP1

DOWN1:
LEA DX,MSG2
CALL MESSAGE
LEA SI,STRING

LOOP2:
MOV BL,[SI]
SUB BL,32
MOV [SI],BL
INC SI

DOWN2:
MOV BL,[SI]
CMP BL,0DH
JZ DOWN3
MOV DI,SI
INC SI
JNE DOWN2


DOWN3:
MOV SI,DI
MOV BL,[SI]
SUB BL,32
MOV [SI],BL
LEA DX,STRING
CALL MESSAGE

MOV AH,4CH
INT 21H
MAIN ENDP

MESSAGE PROC
MOV AH,09H
INT 21H
RET
MESSAGE ENDP

INPUT PROC
MOV AH,01H
INT 21H
RET
INPUT ENDP

END MAIN

Output
ENTER THE STRING :anandhu
THE RESULT IS :AnandhU