TASEmulators / TASEmulators/BizHawk

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

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re: gamedb/FWdb and heuristics Request: Feature/Enhancement
Dominant language
C#
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Description

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.

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Research direction

Start by tracing BizHawk's ROM-loading and core-selection entry point, since the issue names no specific file or test. Check for the 16-byte Genesis/Mega Drive header at offset 0x100 only when the ROM is long enough, then verify that matching ROMs are sent to the Genesis core.

Written by the indexing model from the issue text.

Assessment

Tech stack
csharp
Domain
game-dev
Issue type
Feature
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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