Games that use decimal mode

Discuss emulation of the Nintendo Entertainment System and Famicom.

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NewRisingSun
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Games that use decimal mode

Post by NewRisingSun »

There are at least two Famicom games that require decimal mode: the original Bit Corp. releases of Duck Maze and Othello. These games must have been developed on a Famiclone with a decimal-mode-bearing CPU. When run on an original Nintendo console, or an accurate emulator, these games glitch whenever a digit crosses the 10 mark. Here is an example: https://youtu.be/uCOt5GVpBc4
The Australian HES releases of these two games were updated to no longer require decimal mode, as HES must have insisted that these games run on original Nintendo consoles.

As for emulator support, one could just add an "Allow Decimal Mode" option in the emulator's settings, and insist that users enable it by themselves, just as they have to choose input devices by themselves. Theoretically, one could also somehow put this into the NES header, possibly as a Mapper or Submapper to Mapper 0, since both games use simple NROM boards. Using any other bits of the header just for two games would be rather wasteful.
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Bregalad
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Re: Games that use decimal mode

Post by Bregalad »

I'm pretty sure the emulator REW incorrectly simulates a 6502 with decimal mode available. Also, it's one of the least accurate emus arround (*), probably worse than even Nesticle, but it can be fun to see how games turn out running on this.

(*) Not counting emus targetting small devices such as the GBA or NDS.
zzo38
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Re: Games that use decimal mode

Post by zzo38 »

NewRisingSun wrote:As for emulator support, one could just add an "Allow Decimal Mode" option in the emulator's settings, and insist that users enable it by themselves, just as they have to choose input devices by themselves. Theoretically, one could also somehow put this into the NES header, possibly as a Mapper or Submapper to Mapper 0, since both games use simple NROM boards. Using any other bits of the header just for two games would be rather wasteful.
A mapper or submapper is inappropriate in my opinion. I think that a setting that the user can enable/disable by themself is best, so that you can emulate it both ways.
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rainwarrior
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Re: Games that use decimal mode

Post by rainwarrior »

Well, it's just not something that a mapper can do.

An option in an emulator is perfectly fine. I think you'd meet a lot of resistance if you proposed to add a bit for it to the iNES format. These just aren't really NES/Famicom games to begin with?

TBH the much easier thing to do is just patch the ROM. Or in the Duck Maze case just use the Australian version (I didn't even know there was this different broken version out there?)... or play the better game that it was based on instead: Penguin Land on the SMS.
MLX
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Re: Games that use decimal mode

Post by MLX »

I'm not sure if patching is compatible with the preservation of commercial releases (even through they were sold in tiny quantities). As for Duck (醜小鴨), the original version that made use of the decimal mode was dumped only this year (30 years after its release, it's something).
I mean, Duck is the first commercial unlicensed Famicom title if you ignore Maruo that could be obtained by mail order. So it's nice to have the original ROM around.
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rainwarrior
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Re: Games that use decimal mode

Post by rainwarrior »

?? A patch has nothing to do with preservation. You can preserve it any way you like whether or not a patch exists.
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FrankenGraphics
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Re: Games that use decimal mode

Post by FrankenGraphics »

The angry cinema nerd has a thing to say about that.

https://www.youtube.com/watch?v=XfVj7RtsYxw

Well, he doesn't say it outright, but there might be cases where the preservation of a variant feeds the demise of another.
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AskaJ
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Re: Games that use decimal mode

Post by AskaJ »

rainwarrior wrote:?? A patch has nothing to do with preservation. You can preserve it any way you like whether or not a patch exists.
No man.
I just testing it and I did not get anything done :x
Can be problem in emulator? :?:
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