mov ah, 0x0e ; enable TTY

mov al, "1"
int 0x10
mov al, the_secret
int 0x10

mov al, "2"
int 0x10
mov al, [the_secret]
int 0x10

mov al, "3"
int 0x10
mov bx, the_secret
add bx, 0x7c00
mov al, [bx]
int 0x10

jmp $ ; infinite loop

the_secret:
    ; store 0x58 'X' right before zeropad
    db "X"

times 510-($-$$) db 0
dw 0xaa55