Sonic 3 is hard to work with due to lack of space

[TorutheRedFox]

there should be some way to quickly and easily remove unnecessary padding and unused data to make space, or just extend the amount of space available to the game from 2MB to 4MB

[InfernoGear]

Changing org $200000, which is right before EndOfRom to org $400000 gives 4 MB of space.

[TorutheRedFox]

problem is, Sonic 3 doesn't read anything beyond $200000 anyways

[Chainspike]

I can also confirm that this is a problem, regardless of whether the EndOfRom pointer is $400000.

[TorutheRedFox]

it seems to be an issue with cartram
but idk what exactly causes it to behave differently from S3K

[MainMemory]

I haven't looked at the code, but does S3 ever turn the SRAM access flag off? If you don't turn it off, then the data at $200000+ will always be mapped to SRAM, not ROM.

[TorutheRedFox]

I don't think it does
hmm

[TorutheRedFox]

I tried implementing the SRAM access flag switching, but it makes the game crash on file select
but it does make reading past $200000 possible

[Awuwunya]

Maybe we should have an assembly option to enable these SRAM switches just like how S&K does it?

[TorutheRedFox]

probably
and also make the SRAM switches not make the data select menu freak out

[vladikcomper]

The Data select menu was glitching out due to some code pointers in its objects misrepresented as data. This was fixed in pull-request #28. You may also want to check #29, which fixes even more pointer issues for various in-game objects.

[InfernoGear]

Even with the above pull-requests, there are still two remaining lines of code that break when data is shifted. These lines of code are within 2 of the 4 competition game modes. I've already submitted pull request #30 to fix this issue, so, even though it is not merged yet, I'd recommend applying the changes if you are hacking S3A. Once these are fixed, there should be no more issues with data shifting. All that remains after that as potential issues are the lack of a sound driver disasm and the already mentioned SRAM issues. The SRAM would be the core of this issue, and it should be easily fixable once the data-shifting errors are entirely fixed.