BITS 16

mov bl, 0xFA

.repeat:

in al, 0x60
cmp al, bl
je .repeat
mov bl, al

cmp al, 0x1E
je .a

jmp .repeat

.a

mov cl, 0x41
jmp .print

.print

mov al, cl
mov ah, 0x0E
int 0x10
jmp .repeat

times 510-($-$$) db 0
dw 0xAA55