> > Hi,
> > I've built a disassembler for the NES roms to test the 6502 cpu of my nes
> > emulator. However the disassembler showed many FF opcodes (mostly chained in
> > long groups of FF op's). I used other NES disassemblers to compare the output
> so
> > to rule out errors and I also looked at the binary data directly. So I would
> > like to know why there are so many FF opcodes in Nes roms (e.g. zelda, SMB2,
> > Ninja Gaiden)?
> >
> > Thanks
> >
>
> It's not an opcode -- it's just meaningless data you're looking at. Long runs of
> 0xFF usually mean that part of the ROM has not been programmed with anything.
>
>
> ----
> Bart
>

So why do they have these "gaps" in the program? Why isn't the whole program (game) burnt on the ROM without them (i.e as one big chunk)?