MiSTer FPGA Forum

This game is a known stress test for emulators and FPGA implementations. Though, It seems emulators have been able to run this game for awhile now and wonder if there is enough documentation that explains what is needed to get this game to run properly. Is it a CPU or PPU issue?

I'm sure it will eventually get fixed on the MiSTer core, but just curious if it is already known what causes this game to be such a pita to get working.

Thanks

Edit: Found this interesting article, half of it goes over my head but quite interesting.

https://mgba.io/2018/03/09/holy-grail-bugs-revisited/

The problem appears to be that the interrupt handling of the CPU is not accurate. The timer interrupt is interfering with the Vblank and/or OAM interrupts. I will open an issue on GitHub soon.

Thanks for the info Paul.

Anyways, best of luck to whoever tries to get this game running correctly.