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Emalation on PPC hardware

AndrevS

New member
As the gamecube uses an PowerPC 750 based core. So this is a CPU alike the G3.
Emulation on x86 hardware is very slow at the moment. Is this caused by the PPC emulation?
It was taken very long since there was a decent PPC-Mac emulator for PC (PearPC) for the reason that it's hard to emulate PPC on x86.
So, what are the possebilities for emulating GameCube on a G3/G4/G5 based machine.
Is it possible to have an emviorement working like MOL on a G3 based machine, allowing more speed.
 
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dolqube

Winphin Developer
its an extension of a ppc 750 not a ppc 950. :matrix:

A mac would be very fast for games that do not use the gekko specific instructions
because most of the emulation would be basecally static. :king:

No one has really bothered to code one for it though with the exception of monk.
Even with gcube it doesnt use the macs registers to store the gamecubes registers .ie it uses memory instead. :(

Self modifing code would be less of a problem here to.
Maby someone will get around to coding one, but most people dont have a mac.
Which is why no one really bothered. =]


If a lot more HLE was done and the gamecube emulators for x86 or x64 were dual threaded then we would get full speed games.

It is not enough to HLE the os functions.
We need to start HLEing the gfx and Pad functions.
But first we need gfx emulation to be as complete as possible. :nuke:
 
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dolqube

Winphin Developer
this is not a normal ppc 750.

Its basecally a ppc 750 with sse instructions.
A power pc with pentium advantages.
Which is why it is slow to emulate.

When I said above " A mac would be very fast for games that do not use the gekko specific instructions "

I ment that when these sse like instructions are not used by the gc games then a mac would emulate it at full speed, but they are used in most games if they were not then the games would be pretty average. (which defeats the purpose)

A G3 can have many different cpus a ppc 750 is just one of those.
 

arablizzard2

New member
Its basecally a ppc 750 with sse instructions.
A power pc with pentium advantages.

Where in the world did you get that idea? SSE (2 and 3) are useful for speeding up PowerPC emulation on x86 machines. The PowerPC processors wouldn't have a use for SSE, since they have their own wacky registers, the details of which are beyond me.

I did find this description for the special CPU the gamecube does use though:
The Gekko CPU is actually something of a hybrid 750CXe/750FX processor, boasting features from both the CXe and the FX. Specifically, it has the same cache structure as the CXe and the enhanced 60x bus of the FX. Half of the L1 data cache (16 KB) can be locked as well. Another trait of the FX that can be found in Gekko is a dual-reservation station FPU pipe, allowing for full pipelining in addition to the packed single-precision capability mentioned above.
http://www.aceshardware.com/read.jsp?id=60000288

You'll see that SSE is not mentioned anywhere. :p
 
OP
A

AndrevS

New member
Gekko

Gekko is the custom central processor for the Nintendo GameCube game console. It is based on a PowerPC 750CXe and adds about 50 new instructions as well as a modified FPU capable of some SIMD funtionality. It has 256 kB of on die L2 cache, operates at 485 MHz with a 162 MHz memory bus, is manufactured by IBM on a 180 nm fabrication processor. The die is 43 mm² large.

http://en.wikipedia.org/wiki/PowerPC_G3#Gekko

So there are also 50 aditional instuctions, but how frequent are they used. What does it mean for running GameCube software on PPC hardware.
 

dolqube

Winphin Developer
the gekko extension instructions are
paired-single floating point instructions.

ie. very similar to sse or sse2

I didnt mention sse3
 
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