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SubjectRe: NES rom FF opcode Reply to this message
Posted byBart T.
Posted on07/05/08 02:07 PM



> 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.


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Bart

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Entire Thread
Subject  Posted byPosted On
*NES rom FF opcode  KMDK07/05/08 08:07 AM
..Re: NES rom FF opcode  Bart T.07/05/08 02:07 PM
..*Re: NES rom FF opcode  KMDK07/06/08 09:30 AM
...*Re: NES rom FF opcode  Bart T.07/06/08 03:37 PM
....*Re: NES rom FF opcode  smf07/31/08 05:54 PM