MiSTer FPGA Forum

Another excellent update from @AzumFpg great work on adding a data cache for the PlayStation 1 CPU.

What does that mean in terms of the end experience? E.g. if a game on real hardware runs at 20FPS, but with data cache runs at 30FPS, does that mean that the game plays 50% faster? Or that 50% more frames are rendered for the same amount of "in game" time, making it smoother?

very nice
but im having an issue now with "fast boot" option. when i start the core (fresh start) and select a chd file it wont boot direct. i have to reset console. after that every game boots normal. there was no problems with that before the update

setiawan wrote: ↑Sun Mar 13, 2022 4:40 am What does that mean in terms of the end experience? E.g. if a game on real hardware runs at 20FPS, but with data cache runs at 30FPS, does that mean that the game plays 50% faster? Or that 50% more frames are rendered for the same amount of "in game" time, making it smoother?

This depends on how the engine of the game was designed. Most likely a 3D-engine on a hardware like the PSX aims for the highest possible framerate with variable framerates throughout the game. These games can benefit from such a feature because the game's engine aiming for the highest possible framerate might be running independent from the rest of the game (sound, game logic, etc.).

But I guess you have to test for every title to see if it works.

EDIT: I just tried 3 games. Vanishing Point, Ridge Racer and Tomb Raider III. The first 2 don't change, because their framerate is already locked at 30 FPS. TR III shows a big improvement right at the start, when you slide down at the beginning of the first level, the framerate drops in the lower 20 range. With data cache on you only have a brief drop from 30 to 29 frames.

Robotron X is another game that benefits, the frame rates are about 30% higher when data cache is enabled.

Tomb Raider 3 inside the Manor is close to 30fps at all time now. :0

Sorry if I've missed something obvious in the original post, but how - exactly - does one find and enable this CPU Data Cache feature? I had a quick look in the video and debug options menus but nothing leapt out at me. This was late last night though - maybe my tired eyes glazed over it. Cheers.

JonnyTenebrous wrote: ↑Mon Mar 14, 2022 10:34 am Sorry if I've missed something obvious in the original post, but how - exactly - does one find and enable this CPU Data Cache feature? I had a quick look in the video and debug options menus but nothing leapt out at me. This was late last night though - maybe my tired eyes glazed over it. Cheers.

It is in the Debug Options called something like "Data Cache" and it can be switched on/off. If you don't see it update to the latest unstable version.

Powerslave works well with this feature. The original Saturn game had locked 30fps framerate, while the PlayStation port had an uncapped framerate with constant noticeable dips. Enabling cache makes it run at decent 30+ fps, only dipping to 20 in intense situations.

Awesome work as always. Hopefully he'll be able to implement perspective correction as well. Giving PS1 core a what if PS1 Enhanced mode.