Detect Genesis/Mega Drive ROMs based on Headers in ROM Data

[hegyak]

I checked and all Good/Proper Genesis/Mega Drive ROMs have at Offset 0x100, have the Hexademical values:
"53 45 47 41 20 47 45 4E 45 53 49 53 20 20 20 20"
Or
"53 45 47 41 20 4D 45 47 41 20 44 52 49 56 45 20"

This signifies that it's a Sega Genesis/Mega Drive ROM. My question is, can we read in the ROM at that offset, for 16 bytes, and look for those values? If we see those values, load up the ROM into the Genesis Core.

BizHawk would probably need to verify that the ROM itself has enough bytes to actually reach Offset 100 and has at least 16 bytes beyond that.

[nattthebear]

This will be considered only as part of the larger "autodetect ROMs" task, which no one can agree on the specifics of :(

[zeromus]

Who's demanding this? People with homebrew roms not in the gamedb with strange extensions other than .md so that elementary heuristics cant work?

[hegyak]

@zeromus I marked this myself as Question. Because, I thought it would be best as a question of "can/should we do this?" Not "Let's do this."

And for the same reason, it's priority is Poop. It's not a major or even important thing to worry about. There's plenty of larger issues to worry about, but it is something I wanted to inquire into.

Hearing that there's already a larger plan in place, it makes me want to jump into that discussion but, I think that's a discussion for IRC and not GitHub.

I will leave this open as an idea of what could be done and what could be done concerning Genesis/Mega Drive ROM detection behaviors.

[YoshiRulz]

Is better rom system detection in the issue tracker? I couldn't find it.

[hegyak]

@YoshiRulz As far as I am aware, there is not. The issue is there are a LOT of Systems BizHawk supports. Aside from the Extension, which users can mess with as they see fit, there may not be a consistent way to accurately identify every ROM and ISO that could in theory be loaded.

[nattthebear]

This probably wouldn't live in the core