Loading SNES games off a Gameboy cartridge?

[Ami_]

Gameboy cartridges can be played on a SNES using the Super Gameboy, and sometimes include additional features when doing so. There has been a GB cartridge which contains an entire SNES game (Space Invaders).

My question is: could it be possible to take an existing SNES rom hack, wrap it in GB code, and load it off a GB cartridge through a Super Gameboy?

 

[Kwyjor]

All games running on SGB fo use both CPUs, including the space invaders mode you love so much.

The game in SNES mode uses a resolution and transparencies that the Game Boy is fundamentally incapable of. It's hardly a matter of "red arrows and clicks".
https://blog.loveconquersallgames.com/post/2424872085/fuck-the-super-game-boy-now-youre-playing-with

 

[Deleted member 194275]

The game in SNES mode uses a resolution and transparencies that the Game Boy is fundamentally incapable of. It's hardly a matter of "red arrows and clicks".
https://blog.loveconquersallgames.com/post/2424872085/fuck-the-super-game-boy-now-youre-playing-with

That's 100% true. What is also true, and that's my whole point, is that every single Super Game Boy enhanced game do the same, witch it using some capabilities of SNES to enhance gameboy games, like some that use controller port 2 to play 2 player games, or the colorization of many games, those are all modes that Super Game Boy deliveries.

What is 100% false, is that there is a tiny snes game hidden in a game boy cartridge. That's the click bait on youtube that made people magically forget that running Space Invaders with background and colors is not the same as run a SNES rom.

Come on, you can't even bypass the super gameboy sound chip for fuck sake. Everything that the Super Gameboy runs, is running on the super game boy, why it is so hard to understand?

Some dudes are talking like the SGB is magically bypassing itself and becoming a SNES Flashcard. I wonder is those people ever touched on a SGB or on a SNES before.

 

[SylverReZ]

Try disassembling the Game Boy ROM in an emulator to find the routines on how the SGB process the SNES code into memory. Then you'll get an idea on how it could be possible to inject your own SNES code.

 

[KleinesSinchen]

That's 100% true. What is also true, and that's my whole point, is that every single Super Game Boy enhanced game do the same, witch it using some capabilities of SNES to enhance gameboy games, like some that use controller port 2 to play 2 player games, or the colorization of many games, those are all modes that Super Game Boy deliveries.

What is 100% false, is that there is a tiny snes game hidden in a game boy cartridge. That's the click bait on youtube that made people magically forget that running Space Invaders with background and colors is not the same as run a SNES rom.

Come on, you can't even bypass the super gameboy sound chip for fuck sake. Everything that the Super Gameboy runs, is running on the super game boy, why it is so hard to understand?

Some dudes are talking like the SGB is magically bypassing itself and becoming a SNES Flashcard. I wonder is those people ever touched on a SGB or on a SNES before.

I really don't know why you seem to be so aggressive about this.
The screenshot alone doesn't look like a Super Game Boy enhanced game running at 160*144 pixels.

Finally, I'll quote/link nocash here:
http://problemkaputt.de/pandocs.htm#sgbfunctions

Taking Control of the SNES CPU
Finally, it is possible to write program code or data into SNES memory, and to execute such program code by using the SNES CPU.

 

[SylverReZ]

"Finally, it is possible to write program code or data into SNES memory, and to execute such program code by using the SNES CPU." - there's no screenshots or any other proof from what I could tell to show this claim.

 

[torrent_get]

The super famicom SNES is shown here.

transition gb to sfc timestamp 9m37s.

 

[KleinesSinchen]

"Finally, it is possible to write program code or data into SNES memory, and to execute such program code by using the SNES CPU." - there's no screenshots or any other proof from what I could tell to show this claim.

Let's say it that way: I know it is a possible logical fallacy "argumentum ab auctoritate" and not a proof.

I trust nocash's documentation. I believe he knows what he does and writes in his documentation.
=======

Lacking all abilities in this regard, I can't do reverse engineering myself. Maybe somebody with such abilities could confirm machine code for two different CPUs to end this discussion.

 

[SylverReZ]

Let's say it that way: I know it is a possible logical fallacy "argumentum ab auctoritate" and not a proof.

I trust nocash's documentation. I believe he knows what he does and writes in his documentation.
=======

Lacking all abilities in this regard, I can't do reverse engineering myself. Maybe somebody with such abilities could confirm machine code for two different CPUs to end this discussion.

Yes, he has done many many amazing things - such as the NO$ series of emulators that I have used for years.

 

[Ami_]

Try disassembling the Game Boy ROM in an emulator to find the routines on how the SGB process the SNES code into memory. Then you'll get an idea on how it could be possible to inject your own SNES code.

I tried to do that, but I don't personally have a good enough understanding to reverse engineer this.

 

[SylverReZ]

I tried to do that, but I don't personally have a good enough understanding to reverse engineer this.

http://problemkaputt.de/pandocs.htm#sgbfunctions

 

[Kwyjor]

I found a link at https://archive.nes.science/nesdev-forums/f20/t8307.xhtml that says something about "i replaced the rom in the Europen gameboy version of Space invaders with the euro snes version", whatever that means.

Come on, you can't even bypass the super gameboy sound chip for fuck sake.

Isn't that exactly what happens with an SGB game with an enhanced soundtrack? Like in the link I posted?

 

[PhyChris]

That's rather ambiguous. Isn't everything "custom code"?

What exactly would be the obstacle in overwriting the SNES code in the Space Invaders ROM with some arbitrary homebrew? Presumably there's some checksum somewhere, but aside from that?

?? I meant homebrew.

Edit: You could do some cool stuff that used both CPUs and the SNES PPUs

 

[SylverReZ]

I found a link at https://archive.nes.science/nesdev-forums/f20/t8307.xhtml that says something about "i replaced the rom in the Europen gameboy version of Space invaders with the euro snes version", whatever that means.

That literally doesn't show anything that this is the case.

 

[skawo]

There is definitely something resembling a SNES ROM in there. The game is a modification of Space Invaders: The Original Game, which you can easily see if you compare the footage.

 

[SylverReZ]

There is definitely something resembling a SNES ROM in there. The game is a modification of Space Invaders: The Original Game, which you can easily see if you compare the footage.

They're both the same games, but with some extra features to the gameplay such as replacement stage backgrounds.
https://viewsync.net/watch?v=_-yJMha256c&t=5.77&v=QKsJokBb9bw&t=758&mode=solo&autoplay=true

 

[skawo]

If you hex edit the GB rom and compare it to the SI: TOG rom, you can find parts that very clearly match each other.

It does look like the GB rom lacks some things, like the header, and may be split into chunks, so replacing it isn't trivial, but should theoretically be doable.

 

[SylverReZ]

If you hex edit the GB rom and compare it to the SI: TOG rom, you can find parts that very clearly match each other.

It does look like the GB rom lacks some things, like the header, and may be split into chunks, so replacing it isn't trivial, but should theoretically be doable.

It would be best though to see how the ROM is loaded into memory, just to get an idea on how you can replicate the same thing as what the Space Invaders ROM does.

 

[Ami_]

If you hex edit the GB rom and compare it to the SI: TOG rom, you can find parts that very clearly match each other.

It does look like the GB rom lacks some things, like the header, and may be split into chunks, so replacing it isn't trivial, but should theoretically be doable.

I found 137396 bytes of identical data at these addresses

	start	end
GB	0004C51C	0004F9BB
SNES	0002AC68	0002E107

Curiously 137kb is too big to fit in RAM.

 

[SylverReZ]

I found 137396 bytes of identical data at these addresses

	start	end
GB	0004C51C	0004F9BB
SNES	0002AC68	0002E107

Curiously 137kb is too big to fit in RAM.

It might perhaps be compressed or uncompressed data, have you checked?

 

[Ami_]

It might perhaps be compressed data, have you checked?

No, I'm not sure how.