Notes

.model small
.stack 100h
.data
msg_title db 0Ah,0Dh, '=== PALINDROME CHECKER ===$'
prompt db 0Ah,0Dh, 'Enter a word: $'
is_pal db 0Ah,0Dh, 'Result: The word is a palindrome.$'
not_pal db 0Ah,0Dh, 'Result: The word is NOT a palindrome.$'
newline db 0Ah,0Dh, '$'
buffer db 50 dup('$') ; space for input
len dw 0 ; to store string length

.code
main proc
mov ax, @data
mov ds, ax

; ===== DISPLAY TITLE =====
mov ah, 9
lea dx, msg_title
int 21h

; ===== ASK FOR INPUT =====
mov ah, 9
lea dx, prompt
int 21h

; ===== READ STRING =====
lea dx, buffer
mov ah, 0Ah
int 21h

; Get string length (first byte = max len, second byte = actual len)
mov al, [buffer+1]
mov ah, 0
mov len, ax ; save length in len

; ===== PALINDROME CHECK =====
mov cx, len
mov si, offset buffer + 2 ; start of string
mov bx, si
add bx, cx
dec bx ; end of string

check_loop:
cmp si, bx
jge done_check ; done if start >= end

mov al, [si]
mov dl, [bx]
cmp al, dl
jne not_palindrome ; mismatch ? not palindrome

inc si
dec bx
jmp check_loop

done_check:
; if we reach here, it’s a palindrome
mov ah, 9
lea dx, is_pal
int 21h
jmp exit_program

not_palindrome:
mov ah, 9
lea dx, not_pal
int 21h

exit_program:
mov ah, 4Ch
int 21h
main endp
end main