nitro2k01
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| Most people seem to be interested in hacks they can perform "in the box", i.e. using button input only, with or without tool-assistance. I'm looking for sort of the opposite. Given control over the SRAM contents, I want to run my own code as soon as possible, perhaps without needing to press A to load the file if possible. I plan to investigate this myself, but if there are existing resources on this specific scenario, I'd be interested. |
GuyPerfect
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I'm not clear on exactly what you're trying to do. Could you post a for-instance scenario and step me through it so I have a better idea?
As for the save data, I've got that fairly well documented over yonder. As Pokémon uses MBC3, the SRAM is activated by writing 0x0A to 0x0000, which exposes SRAM banks to 0xA000-0xBFFF. Each SRAM bank is 8KB of the save data, which can be selected into that address range by writing the bank number to 0x4000.
Armed with that knowledge, you should be able to write any boot code you want and have it work with the save data. |
2Tie
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Guy, I believe he means that, while you can technically create your own Gameboy game using the first-gen pokemon games, like in this video or this one for example, he wants to be able to run his own code/program enabled or programmed in the SRAM ASAP (most likely at the Continue screen or upon loading the save).
As for Nitro, I'd look at the links in the description of the first video if you've haven't already. :3
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nitro2k01
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Originally posted by 2Tie
Guy, I believe he means that, while you can technically create your own Gameboy game using the first-gen pokemon games, like in this video or this one for example, he wants to be able to run his own code/program enabled or programmed in the SRAM ASAP (most likely at the Continue screen or upon loading the save).
As for Nitro, I'd look at the links in the description of the first video if you've haven't already. :3
Yes, exactly, abusing the cartridge SRAM as program storage, which I want running as soon as possible. This could be fun/useful for people who own a cartridge flasher and can write arbitrary SRAM.
The only really relevant link there is to VBA-clojure, which is an extremely cool project, but again based on the premise of entering data as keystrokes. With control over SRAM you could perhaps do better. I'll poke around in BGB eventually, which will probably lead to me finding something interesting. |
Sanqui
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SRAM is first touched in the main menu (after title screen). That's the theoretical earliest you could run custom code.
I think the best option would be to insert a custom map header in SRAM, and make it run a custom script. Map scripts aren't executed in the main menu, so I think the best you can achieve is having it run your code as soon as you hit CONTINUE.
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stag019
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| Posted on 12-10-13 07:17:02 PM (last edited by stag019 at 12-10-13 09:49:41 PM) |
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The easiest way would probably be this:
http://forums.glitchcity.info/index.php/topic,6638.0.html
You would still have to go into the game and select an item, but that doesn't take too long.
I could write you up a save file that has all the data in the proper place in the save file, and point you to a big chunk of save data that you could use (probably the Pokemon in the boxes).
Edit: Combining Sanky and my idea I have a .sav file now for Pokemon Red or Blue that, when hitting the continue button, causes the code in the .sav file at 0x30C0 to run (and you have at least 0x462 bytes to work with). The only problems are: - There is a checksum on these bytes that must be fixed. I wrote a quick and dirty small tiny C program for that: here
- Once it run and you return, it runs the code again for every frame you're on the overworld for. I don't know how important this is to you.
If you want me to fix the second one, I'll look for a way to do that; if not, just ask and I'll upload the .sav file somewhere.
Edit 2: Done with the fixing thing. Download here. And if someone wants to mirror this because I can't guarantee it will always be available. |
