Capcom Classics Mini Mix

Discuss emulation of the Nintendo Entertainment System and Famicom.

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NewRisingSun
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Capcom Classics Mini Mix

Post by NewRisingSun » Sat Feb 13, 2021 3:35 am

The collection Capcom Classics: Mini Mix for Game Boy Advance includes a modified build of PocketNES to run three NES games. The ROM data has been modified for protection purposes: they use normally-unused opcodes with non-standard meaning.

Is it worth adding a NES 2.0 Console Type just for these three games extracted from that collection, to account for a CPU having these nonstandard opcodes? If it were some bootleg collection, I would immediately say "HELL no", but since this is a licensed collection, I am not sure.

tepples
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Re: Capcom Classics Mini Mix

Post by tepples » Sat Feb 13, 2021 9:06 am

If I remember correctly, the Nintendo 3DS Virtual Console version of the Pokémon games also uses undefined SM83 opcodes to mean emulator-specific things. In my opinion, the proper form for this package is a 3DS ROM, not an NES ROM. Adding a console type for an emulator would be like adding an "Emulate NESticle quirks" console type.

As an aside: What's the evidence that Capcom Classics: Mini Mix uses PocketNES, not some other emulator?

ArcticCircleSystem
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Re: Capcom Classics Mini Mix

Post by ArcticCircleSystem » Sat Feb 13, 2021 10:15 am

tepples wrote:
Sat Feb 13, 2021 9:06 am
If I remember correctly, the Nintendo 3DS Virtual Console version of the Pokémon games also uses undefined SM83 opcodes to mean emulator-specific things. In my opinion, the proper form for this package is a 3DS ROM, not an NES ROM. Adding a console type for an emulator would be like adding an "Emulate NESticle quirks" console type.

As an aside: What's the evidence that Capcom Classics: Mini Mix uses PocketNES, not some other emulator?
The Capcom collection is for the Nintendo GBA, and we were able to dump the three ROMs using a tool designed for PocketNES, so that certainly supports it. ~Charlie
Last edited by ArcticCircleSystem on Sat Feb 13, 2021 9:06 pm, edited 1 time in total.

calima
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Re: Capcom Classics Mini Mix

Post by calima » Sat Feb 13, 2021 11:21 am

What's the point? The modification's purpose is expressly against that. Documenting it just means the next project will change it.

ArcticCircleSystem
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Re: Capcom Classics Mini Mix

Post by ArcticCircleSystem » Sat Feb 13, 2021 4:34 pm

calima wrote:
Sat Feb 13, 2021 11:21 am
What's the point? The modification's purpose is expressly against that. Documenting it just means the next project will change it.
I highly doubt they'll change their copy protection's behavior based on a DS game composed of three rereleased NES games being emulated after 17 years. If they do adopt a new copy protection method for one of their retro releases after this, chances are they were going to do it no matter what. ~Charlie

lidnariq
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Re: Capcom Classics Mini Mix

Post by lidnariq » Sat Feb 13, 2021 4:37 pm

Another related point is that NRS has already assigned 12 of the 16 possible values for that field, and that's getting uncomfortably close to running out.

NewRisingSun
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Re: Capcom Classics Mini Mix

Post by NewRisingSun » Sat Feb 13, 2021 4:43 pm

We still have four more bits to broaden the field. :twisted:

ArcticCircleSystem
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Re: Capcom Classics Mini Mix

Post by ArcticCircleSystem » Sat Feb 13, 2021 5:55 pm

Yeah, and again, this is a licensed release. From Capcom. Also the fact that it was Capcom that did this should not surprise anyone, just look at the Capcom Suicide Battery and the fact that NewRisingSun had to define a whole new input type because Capcom did something weird to the inputs on their plug n' play as a form of copy protection. ~Red

lidnariq
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Re: Capcom Classics Mini Mix

Post by lidnariq » Sat Feb 13, 2021 7:25 pm

For my own curiosity, what's the changes in behavior of these rereleases? Are they different from the original games? Or are the new instructions just to get in the way of extracting the ROMs and using them in a general purpose emulator?

ArcticCircleSystem
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Re: Capcom Classics Mini Mix

Post by ArcticCircleSystem » Sat Feb 13, 2021 8:41 pm

lidnariq wrote:
Sat Feb 13, 2021 7:25 pm
For my own curiosity, what's the changes in behavior of these rereleases? Are they different from the original games? Or are the new instructions just to get in the way of extracting the ROMs and using them in a general purpose emulator?
Unclear. Might have some changes to dates, but in any case, they are official releases and thus should probably be emulated. ~Red

lidnariq
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Re: Capcom Classics Mini Mix

Post by lidnariq » Sat Feb 13, 2021 9:02 pm

On the one hand, yes.

On the other hand, they can already be emulated as a DS game. And they never existed in a form that could run on an actual physical console containing a 6502 core. And there's literally an infinite number of variations that could be made at the emulator level to quickly exhaust our ability to encode them. By requiring a physical hardware release on a physical famiclone, we can at least move the scope to something that requires a significant hardware investment by those publishing things.

But personally, my opinion really comes down to: are these interestingly different, or are they just the original releases with DRM added?

ArcticCircleSystem
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Re: Capcom Classics Mini Mix

Post by ArcticCircleSystem » Sat Feb 13, 2021 9:06 pm

lidnariq wrote:
Sat Feb 13, 2021 9:02 pm
On the one hand, yes.

On the other hand, they can already be emulated as a DS game. And they never existed in a form that could run on an actual physical console containing a 6502 core. And there's literally an infinite number of variations that could be made at the emulator level to quickly exhaust our ability to encode them. By requiring a physical hardware release on a physical famiclone, we can at least move the scope to something that requires a significant hardware investment by those publishing things.

But personally, my opinion really comes down to: are these interestingly different, or are they just the original releases with DRM added?
For some reason I said DS when I meant GBA, sorry about that. We're not entirely sure, but again, these are official releases that are meant to be run unmodified. If this were some bootleg bullshit, obviously that'd be another story. ~Red

lidnariq
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Re: Capcom Classics Mini Mix

Post by lidnariq » Sat Feb 13, 2021 9:48 pm

But it's really not. "Official commercial release" has never been the metric for whether something is a NES game. Especially when it can't run on a NES or an existing famiclone without being patched first.

ArcticCircleSystem
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Re: Capcom Classics Mini Mix

Post by ArcticCircleSystem » Sat Feb 13, 2021 10:57 pm

lidnariq wrote:
Sat Feb 13, 2021 9:48 pm
But it's really not. "Official commercial release" has never been the metric for whether something is a NES game. Especially when it can't run on a NES or an existing famiclone without being patched first.
I mean... They are NES ROMs. Officially released. By Capcom. In an emulator in a GBA cart. An NES emulator that runs the ROMs without any runtime patching. ~Red

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tokumaru
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Re: Capcom Classics Mini Mix

Post by tokumaru » Sun Feb 14, 2021 12:18 am

I'm with lidnariq here...
ArcticCircleSystem wrote:
Sat Feb 13, 2021 10:57 pm
They are NES ROMs. Officially released. By Capcom. In an emulator in a GBA cart. An NES emulator that runs the ROMs without any runtime patching.
They're modified NES programs that don't work on real NES hardware anymore... at this point they could be considered just data files required by the GBA game, which's emulating a machine similar to the NES, but not quite. Being an official GBA release doesn't automatically make its data files official standalone releases, specially if they only work with the particular emulator they came packaged with.

I personally wouldn't waste precious NES 2.0 resources with hacks that don't work on real NES/Famicom hardware and don't bring anything new gameplay-wise.

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