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Eric
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Codemaster's Memory Architecture
Post Posted: Tue Sep 07, 1999 4:11 pm
I assume the problems with dumping and emulating Codemaster's games is related to a unique paging scheme used in their cartridges.

It seems that Codemaster's could create any paging scheme they wanted, limited only by the predefined area reserved for RAM. Does anyone have any information about how paging works in Codemaster's games?

Specifically, are pages still 16K? Are the paging registers still at 0xFFFC-0xFFFF?

Thanks.

Eric
 
  • Joined: 24 Jun 1999
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  • Location: Paris, France
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Post Posted: Tue Sep 07, 1999 5:36 pm
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> I assume the problems with dumping and emulating Codemaster's games is related to a unique paging scheme used in their cartridges.
> It seems that Codemaster's could create any paging scheme they wanted, limited only by the predefined area reserved for RAM. Does anyone have any information about how paging works in Codemaster's games?
> Specifically, are pages still 16K? Are the paging registers still at 0xFFFC-0xFFFF?

Basically, it seems to be the same except that paging is done via writing to 0x0000, 0x4000 and 0x8000. But of course there is Murphy's Law around, and dumping a rom and emulating it that way won't work.
Fantastic Dizzy also use a stretched video mode (no vertical scrolling, but the whole vertical area is shown).

I can send you the first 32 kb of the ROM which are definitively a good dump, so you can try disassembling the game and figuring more =)
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Eric
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Post Posted: Tue Sep 07, 1999 6:39 pm
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> > I assume the problems with dumping and emulating Codemaster's games is related to a unique paging scheme used in their cartridges.
> > It seems that Codemaster's could create any paging scheme they wanted, limited only by the predefined area reserved for RAM. Does anyone have any information about how paging works in Codemaster's games?
> > Specifically, are pages still 16K? Are the paging registers still at 0xFFFC-0xFFFF?

> Basically, it seems to be the same except that paging is done via writing to 0x0000, 0x4000 and 0x8000. But of course there is Murphy's Law around, and dumping a rom and emulating it that way won't work.
> Fantastic Dizzy also use a stretched video mode (no vertical scrolling, but the whole vertical area is shown).

> I can send you the first 32 kb of the ROM which are definitively a good dump, so you can try disassembling the game and figuring more =)

I'd be happy to. You can e-mail it to the e-quinn@elnet.com
 
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