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broken?
 
Category: ROM data
Reference: 2811
Closed (rejected) by: root.
kshin98 » 2010-02-04 16:33:45

The following nes roms from the newest no-intro NES set seem to be wrong:

Galaxian (Japan).nes
Galaxian (Japan)(Rev A).nes


The dat reports these roms to have a size of 16k, which is an impossible size for the nes rom.
A normal Nes catridge has minimum of 16k bytes of PRE rom + 8k bytes of CHR rom, which leaves us the minimum of 24k bytes at least.

The dat's roms seem to missing the CHR rom portion or inappropriatly crapped.
And of course, none of these work with neither nestopia or fceux.
kazumi213 » 2010-02-04 22:30:45

Correct PRG-ROM size in both revisions is 8 kbyte. The game not working on emu is a iNES header limitation, can't handle such PRG size.
kshin98 » 2010-02-05 03:00:45

Hmm... Then, it must be mirrored 4 times over 8000h ~ FFFFh, which is 32k ROM region of NES hardware.
(6502 requires the rom to be addressable at FFFBh ~ FFFFh)

I guess we can assign a new mapper number to these 8k PRG roms, and ask emulator author to support it. These are easy to emulate, which can be as simple as mirroring an address range 4 times. There are, as you know, a lot of spare iNes mapper numbers.

The only problem is that there is nobody who's in charge of standardizing iNes mapper numbers.
I don't know but MESS team may do this?
(But don't count on me asking them, though :(. I'm too shy for this. )