Bug at 8F: Game scripting exposed

[Naridar]

I found a strange bug at the eight floor which exposes the game's scripting to us. Spoilers:

[spoiler]At where you buy a warp wire from the guard (only availble at password games), you can see a mistyped script, which shows us how the game's scripting is done. Maybe we could decode it and then modify the game to our needs? That would be awesome.[/spoiler]

[Kitsunexus]

You could certainly do that! However there's the little matter of dumping the ROM, disassembling the code (which is not easily done when it's compiled), reverse engineering, not just how the scripting engine works but how it translates to game code and also find out why the script was in error in the first place and fix it, then patching the fixed ROM back into place to see if it's correct. This can be tricky, because even if you can compile it back to the original programming language it was written in, there's a chance that Atlus might not have changed the language for the commenting in the code (programmer's notes that tell you what the code does) meaning you'd have to be able to understand Japanese, or worse yet, they might have erased commenting entirely, or programmed in a language that lacks commenting. After you got the code dumped and compiled into a workable state you would then have to write PC software for the script editor/patching program (as you're not going to want to modify the whole game in assembler, it'd be better to have a nice little GUI-driven editor) and most importantly you'd have to figure out EO2's memory compression scheme and write a ROM expander to make as many modifications as you want, because if you just edit the game as it is now and add more modifications than there are original scripts, it will have an invalid checksum (the integrity of the data will be corrupted) and it will most likely introduce crashing bugs either at bootup (making debugging a NIGHTMARE) or at the specific script. Also since a ROM expander would be required for anything worthwhile, you can forget about flashing the patched ROM back to the original cart. You'd either have to flash it to the internal DS memory, run it from a card like the R4DS, or design and manufacture your own special cart (I can explain that process to you, but it's a can of worms that might be breaching the TOS defined by Maxine).

If you are capable and willing to do this (and have the time/resources available), I wish you good luck in your endeavors. ^_^

EDIT: Also, to the best of my limited knowledge, currently no DS emulator exists that can play this game. It's a terrible idea to keep dumping changes to ROM to test them as this is EXTREMELY slow and you won't be able to get anything done that way. You would either have to code a DS emulator for this game (or hack an existing one) or modify your system to download code directly from your PC.

[Paranoia]

There is a working DS emu, it's where I get my pics . But yeah, the coding is rather difficult, Only Terence from GFaqs has done it, although I think Scy on this board also did. But they were just searching for the damage values and such, not to change the code.

[scy]

Oh no, it's more complicated than that. It's standard assembly code from what I can tell but it's all sorts of "haha, we feel like messing with you." It's definitely harder to figure out than most other games have been. I haven't done too much else on figuring things out from the code out of laziness though.

Decompiling it and all that is pretty easy though. Find the ROM, run dslazy, you win!

[Kitsunexus]

[Naridar]

[Paranoia]

Yay, Can you do it for the EO one aswell? I lost the program that did it for me.

Btw it's illegal to use a ROM regardless of owning it. The 24 hour rule was just BS so people felt better.

[Kimiko]

[Kitsunexus]

[scy]

[Kitsunexus]

[scy]

Sorry, I was vague I guess; meant in regards to the game data for formulas, skill numbers, and all that. I actually haven't messed with extracting the sound or anything like that.

[Kitsunexus]

[ZetaBladeX13]

[Kimiko]

It's not the rom hacking itself I thought questionable, but the sharing of midis from the game. I'll leave that up to the mods though.