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Old 15 August 2014, 09:11   #41
Toni Wilen
WinUAE developer
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 42
Posts: 20,495
Originally Posted by Mequa View Post
Another thing: I am curious why PearPC's JIT was suggested for future WinUAE PPC emulation, since as far as I am aware PearPC is not actively maintained and is considered quite slow. How about a PPC JIT core from QEMU, or Dolphin (Gamecube/Wii emulator) - the latter is quite fast, if a recent i7 can comfortably emulate a 700MHz+ PPC CPU (and potentially more), this may be quite fast for OS4.x (and/or MorphOS).
I explained it in beta thread. Probably twice.

PearPC: simply because CPU emulator was really simple to detach from main PearPC code.

QEMU: Not going to be possible without someone who knows QEMU inside out. CPU cores and JIT (TCG) is deeply connected to QEMU internals.

Dolphin: If someone can guarantee PPC CPU is 100% 603/604 compatible, with some simple tweaks. (I don't think so). It is also console emulator (vs generic computer) and unused CPU features are rarely emulated (that may be used by some computer OS).

Speed is not important, speed comes last if ever. Check any other emulator!

Also, I have seen any qemu vs pearpc tests that actually compare same things. Exact same code generated by exact same compiler running on exact same OS and code that does not depend on any hardware expansions, just pure CPU.

My understanding is that the PPC JIT from SheepShaver (PPC classic Mac emulator) lacks MMU support which is needed for OS4.x. I'm not sure if MorphOS (whether the classic PowerUP Free Edition, or the current 3.x builds) has the same MMU requirement as OS4.x there.
Even PowerUP and WarpOS require MMU, at least partially.
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