Mappers that Emulators forgot about

Discuss emulation of the Nintendo Entertainment System and Famicom.

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Great Hierophant
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Mappers that Emulators forgot about

Post by Great Hierophant » Tue Apr 26, 2005 6:39 am

The simple question is, what is the proper mapper number for the Maxi-15 and Super Mario Bros+Tetris+Nintendo World Cup carts? I don't know if there is any "recognized" number for these carts, but there should be. Unlike other newer dumps, as these games use unusual mappers (the Maxi-15 mapper being documented only recently.) I get no luck with using mapper 47 for the SMB multi or 231 for the Maxi-15 on most emulators.

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Quietust
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Post by Quietust » Tue Apr 26, 2005 10:28 am

Maxi-15 is mapper 234, not 231 (and the mapper info has been available for at least 3 years now, if not longer)

SMB+Tetris+NWC, on the other hand, was never assigned a proper mapper.
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Great Hierophant
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Post by Great Hierophant » Tue Apr 26, 2005 8:25 pm

Well, that fixes Maxi-15 on the emulators that support it properly, (like FCE Ultra, VirtuaNES and Nintendulator.) But I suppose that also means that the SMB+Tetris+NWC can't really be emulated consistently as it has no mapper number. (VirtuaNES does emulate it properly with mapper 47 assigned as does Nestopia which uses its own database.)

Of the 255 mapper numbers available in the iNES format, surely there is one number free to use. Its not like the hardware that is in the cartridge is much more complicated than mapper 4 or 47. Why should they be "reserved" for pirate cartridges and the like rather than used for true Nintendo hardware? If Squeedo ever sees a release, then a number may be designated for that, provided its PIC controller can be feasibly emulated. Couldn't UNIF help here, designate its board name and go from there.

tepples
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Post by tepples » Tue Apr 26, 2005 8:56 pm

Great Hierophant wrote:But I suppose that also means that the SMB+Tetris+NWC can't really be emulated consistently as it has no mapper number.
Do we forget UNIF already?
Its not like the hardware that is in the cartridge is much more complicated than mapper 4 or 47.
Isn't Tetris an MMC1 game? Or is it mapper-hacked for MMC3 in order to be compatible with N World Cup?
If Squeedo ever sees a release, then a number may be designated for that, provided its PIC controller can be feasibly emulated. Couldn't UNIF help here, designate its board name and go from there.
Darn right. We haven't forgotten UNIF.

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Post by Josh » Tue Apr 26, 2005 10:00 pm

In my opinion, until a more coherent NES file format like UNIF is adopted, the best way to handle emulation of mappers is simply to use a big fucking CRC32 database containing data for all known dumps. Quite a few NES emulators already do this. That way, it doesn't matter if the ROM still has "DISKDUDE!!!" in the header, or someone set the mirroring wrong, or any of that crap. Users could be prompted to select the correct board info for games that are not in the database. For hacks, the user could have an option to take the board/mirroring/other info from an existing ROM CRC entry.

We really, really, really need to kill the iNES file format. I've been working on an idea for this - I don't think we're ever going to get rid of iNES as long as our replacement format is not backward-compatible. So I'm working on a draft specification of a backward-compatible format that will enable sophisticated ROM identification by using a tag on the end of an iNES-format file. That way, existing emulators will use the legacy header, and new emulators will use the tag to obtain UNIF-like accuracy.

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Post by tepples » Wed Apr 27, 2005 7:13 am

Easy way: Make the stuff on the end a proper UNIF file but without the prg and chr chunks. Then emulators can reuse their existing UNIF loaders, and IPS patches continue to work.

Great Hierophant
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Post by Great Hierophant » Wed Apr 27, 2005 8:22 pm

I thnk we should ask the question, what exactly is the hardware inside one of these carts? Can anyone open one up and tell the rest of us the board name and whether it uses discrete components or glop tops? It may be a glop-top board like the other Nintendo multis. Could there be an MMC1 and an MMC3 on the board? I don't know why Tetris needs an MMC1 when all it has is 32KB of PRG ROM and 16KB of CHR ROM. A CNROM cart would do just as well. Mirroring control doesn't seem to be much of a concern when the screen doesn't scroll. It doesn't use battery backed RAM.

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Post by tepples » Wed Apr 27, 2005 10:04 pm

Great Hierophant wrote:I don't know why Tetris needs an MMC1 when all it has is 32KB of PRG ROM and 16KB of CHR ROM. A CNROM cart would do just as well.
MMC1, unlike CNROM, can bankswitch two independent 4 KB CHR banks. I think the ending screens for a high score in A-type and completing B-type use this.

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Post by Great Hierophant » Tue May 10, 2005 3:14 pm

Can anyone tell me the proper mapper number for Death Race? FCE Ultra uses 144 but no other emulator seems to support that one. 11 gives Bad Op code in Nintendulator and Undefined Order in VirtuaNES.

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Post by Nessie » Tue May 10, 2005 11:34 pm

Death Race uses #144, it's almost identical to #11:

http://www.tripoint.org/kevtris/mappers ... /agci.html

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