Can we get a HENkaku port?

[Coldbird]

(08-06-2016 08:21 PM)[Unknown] Wrote:  Not sure. I've read contradictory information about the CPU speed of the Vita - it sounds like the hardware is capable of more, but it may be locked to a max 444 Mhz. If that's the case, performance will probably not be great.

Also, from some educated looking Twitter posts, it seems that the Vita includes a MIPS processor - and runs PSP games on this processor. I wonder if it contains the PSP's GPU as well, because if so that would easily explain how it can run well on PowerVR.

Given that, PPSSPP may not be able to bring a lot to the table... not sure. But if it's a 444 Mhz clocked ARM device with dedicated PSP hardware for its built-in emulator, then hoping for 2x PSP resolution doesn't sound very likely.

Even if it can be clocked up to 2 Ghz, PPSSPP currently has tons of problems specifically on PowerVR SGX543 (the GPU Vita uses.) Some seem like OpenGL driver bugs, but I'm not sure how capable it would be for some of the trickier effects. If the Vita actually uses the PowerVR for its PSP emulation, I'd be very interested in what tricks they're using - it probably involves accessing the hardware and VRAM directly, though (which we can't do generally on Android, PC, etc. - so PPSSPP is not written to do this.)

-[Unknown]

Well... technically it all depends on how you are going to play your cards here.

We know from the way PSP games operate on the Vita in the built-in emulator, that the thing runs both CPUs at the same time, with the "PSP" one doing the actual PSP work, and the media engine (PSP co-processor) being high-level emulated on the ARM CPU of the Vita.

Sony dubbed this mechanic "kermit", and essentially everything that isn't "kermit-emulated" runs on the PSP CPU.

The stuff that is "kermit-emulated", has a RPC-library inside the PSP CPU scope, which sends HLE requests to the ARM-CPU outside the sandbox, processes its things there, and returns the result in regular RPC fashion back to the sandboxed PSP CPU.

In this scenario, it would still be possible to get the PPSSPP goodness into play here, although with a tad bit more work involved.

One could, instead of rendering to a virtual 480x272 framebuffer and then shoveling it outside to the Vita OS via "kermit", just shovel the whole GE-command chain outside to the Vita OS via "kermit".

This way one wouldnt be bound to a artificially smaller framebuffer, and could re-render things using the regular PPSSPP pipeline.

The issue with this though is that, although all of this is entirely possible to do now that henkaku has been released, none of the functions involved for firing up the PSP CPU have been documented / mapped yet.

This is because those calls are not part of the official Vita SDK.
Once mapped and documented properly though, PPSSPP can definitely make use of the MIPS CPU.