Game Genie emulation

Rationale

Allowing cheat codes using the Game Genie (et all, including Game Shark) code is a plus in allowing more emulation use cases.

Description

Intercept the Cartridge reading functions (without performance penalty) and patch reading according to the Game Genie codes.

Notes

It might be interesting to offer also some support to the CHT cheat file format used by libretro and Retroarch.

References

• GB Pandocs - Game Genie (ROM patches)
• Game Genie Encryption Schemes
• Reddit - Gameboy Color CHT files
• Reddit - How do GameShark/GameGenie codes work?
• Sameboy - cheats.c
• Libreto cheats (.cht files)