BITS 16
SECTION .text
ORG 0h
_start
sti
mov	ax,0xb800
mov	es,ax
mov	ax,0720h
mov	di,0
mov 	cx,2000
rep	stosw
mov	dx,_buf
mov	ah,3fh
mov	bx,0
mov	cx,20
sti
int	21h
mov	ax,0xb800
mov	es,ax
mov	si,_buf
mov	di,0
.l
lodsb
jz	.exit
stosw
loop	.l
.exit
hlt

SECTION .data
_buf	 db 'questa frase verra` sovrascritta',0