http://devdocs.inightmare.org/x86-assembly-dos-fil e-inputoutput/
toto proste musi fungovat (OFFSET tam mozes pridat to zavisi od compilera):
filename db "smth.txt",0
mov ah, 0x3Dh
mov al, 2 ; open attribute: 0 - read-only, 1 - write-only, 2 -read&write
mov dx, filename ; ASCIIZ filename to open
int 21h