[Question] How to apply new cheats on libretro core?

[vanfanel]

Hello there,

I am trying to apply a 60 FPS "cheat" for Rez (EU) on the Flycast core.
The cheat comes from here and is supposedly a widely known cheat: https://darkok.xyz/rez/
...but it doesn't do anything.

So far I have tried to add it via Quick Menu -> Cheats in the exact same format that is displayed on the page, like this:
020d06e4 e401d105
And then I add a second cheat for:
020d06e8 2142000b

I have enabled `Auto-Apply Cheats during game load", too.
However, the cheat doesn't do anything.

Does the Flycast RetroArch core need special cheat codes?

[flyinghead]

This cheat seems to work for standalone Flycast so it should work for the Flycast core as well. However RetroArch itself doesn't seem to support cheat codes in this format. The Flycast core doesn't support emulator-handled cheats, only retroarch-managed ones.

[vanfanel]

This cheat seems to work for standalone Flycast so it should work for the Flycast core as well. However RetroArch itself doesn't seem to support cheat codes in this format. The Flycast core doesn't support emulator-handled cheats, only retroarch-managed ones.

Ah, thanks for clearing things up!
Is there a way to "convert" this cheat to a retroarch-managed cheat code? Or maybe such a code is already available?

Another option would be to add it to cheats.cpp inside the core code: since I do my own builds, I could easily test that.

[flyinghead]

You can use standalone Flycast to convert this code to retroarch format: it will create a .cht file that should be compatible.
Otherwise you can do it manually since it's a simple cheat:
write 32-bits value e401d105 at address 0d06e4
write 32-bits value 2142000b at address 0d06e8

[vanfanel]

You can use standalone Flycast to convert this code to retroarch format: it will create a .cht file that should be compatible. Otherwise you can do it manually since it's a simple cheat: write 32-bits value e401d105 at address 0d06e4 write 32-bits value 2142000b at address 0d06e8

Ah, that was so easy to do, thanks! I composed the Retroarch-managed cheat with that, and it works perfectly well.

Do you know if it's possible to hexedit that into the game's disc dump?
Would be cool to have a personal 60FPS version without having to load cheats into it.
Redump uses 3 bin tracks.

What I mean is... What is 0x0d06e4 relative to? Game executable? Data track?