assume cs:code code segment start: mov ax,cs mov ds,ax mov si,offset do0 mov ax,0 mov es,ax mov di,200h mov cx,offset do0end-offset do0 cld rep movsb mov ax,0 mov es,ax mov word ptr es:[0*4],200h mov word ptr es:[0*4+2],0 mov ax,4c00h int 21h do0: jmp short do0start db "overflow!" do0start: push cx mov ax,cs mov ds,ax mov si,202h mov ax,0b800h mov es,ax mov di,12*160+36*2 mov cx,9 s: mov al,[si] mov es:[di],al mov al,2 mov es:[di+1],al inc si add di,2 loop s pop cx mov ax,4c00h int 21h do0end: nop code ends end start