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About GC emulation

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Cyberman

Cyberman

Moderator
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There are same rather challenging problems with emulating the GC .. one of which is the PPC chip has custom opcodes.. just like the the N64 machined does. These opcodes are MMX style instructions for handling audio graphics and other things. I'm uncertain of the GPU details and it's not a keen interest too me to be honest :).

The game cube will be about the same as the N64 in emulating it will take a lot of time and patience. As for bios and the chips in the gamecube, ehhhh grey area there. Physically removing the chip from the board to grab the bios is also a good way to wreck the IC and invalid it's data permanently. I might also point out Nintendo has been noted for encrypting there roms. It's like the bios included with the GC is either extremely simple or it's encrypted so you may be able to get it's contents but it's contents are useless anyhow.

I'll let someone else figure it out ;)

Cyb
 
D

DreamlanD

New member
Cyberman said:
There are same rather challenging problems with emulating the GC .. one of which is the PPC chip has custom opcodes.. just like the the N64 machined does. These opcodes are MMX style instructions for handling audio graphics and other things. I'm uncertain of the GPU details and it's not a keen interest too me to be honest :).
Click to expand...
Probably they would be like Altivec, just standard SIMD extensions which could be easily emulated through SSE/3DNow. It might also be possible to do some HLE stuff with the opcodes, since the G3 is not very powerful compared to the latest 2 GHz+ CPUs.
The game cube will be about the same as the N64 in emulating it will take a lot of time and patience. As for bios and the chips in the gamecube, ehhhh grey area there. Physically removing the chip from the board to grab the bios is also a good way to wreck the IC and invalid it's data permanently. I might also point out Nintendo has been noted for encrypting there roms. It's like the bios included with the GC is either extremely simple or it's encrypted so you may be able to get it's contents but it's contents are useless anyhow.

I'll let someone else figure it out ;)

Cyb
Click to expand...
That could be a problem but I don't think it would be very difficult to decrypt. Also the GC OS is very high level, so it would be easy to emulate most of the functions.
 
Tagrineth

Tagrineth

Dragony thingy
Actually that's a good point, GameCube HLE should be at least within reason. But we're still stuck at the biggest hurdle of them all, the discs themselves... :)
 
JuGz

JuGz

Heavy Metal Master
Cyberman said:
There are same rather challenging problems with emulating the GC .. one of which is the PPC chip has custom opcodes.. just like the the N64 machined does. These opcodes are MMX style instructions for handling audio graphics and other things. I'm uncertain of the GPU details and it's not a keen interest too me to be honest :).
Cyb
Click to expand...

Is there any resource where to find opcodes and custom instruction set of the ngc's cpu?
 
RJARRRPCGP

RJARRRPCGP

The Rocking PC Wiz
Tagrineth said:
OK. Here's the deal.

Vchart20: Xbox is using something halfway between a P3 and a Celeron. It's also using a modified nVidia GeForce3.

Others: GCN would be hard to emulate, almost entirely due to SOUND (which has to be done on the CPU, or it could be done HLE for MusyX-using games, in theory) and the video, which was developed entirely by ArtX, NOT ATi. The Flipper video chip uses a diferent, specialised method for register combiners called 'TEV' - the main difference between TEV and pixel shaders being that TEV can combine reads and ops, so emulating the TEV on a pixel shader would be VERY inefficient (severely multipass). Also Flipper can apply 8 textures in a single pass, which would have to be redone as multipass on anything pre-R300 (with the exception of Kyro and *I think* Savage2000).

Then of course there's the issue of emulating PowerPC on x86 processors. :) Even on MACs, the problem is the Gekko isn't just a 750, it's modified (new instructions for better game performance).

And finally the most obvious thing, GCN discs aren't quite DVD format, they're slightly different. :) So you'd have to find a way to hook a GCN up to a PC to rip the disc (a la DreamCast).
Click to expand...

The XBox uses a Pentium III 733 mhz.
 
Stez02k

Stez02k

*~ Mr. Trance ~*
meaning it would be easier to emulate the XBox, well quite a lot of emulation wouldnt be needed if u already have a PIII and a Nvidia card, anyway, GC emulation wont happen, well at the moment it wont, until then play some Xbox games on ya pc when a decent Xbox emu comes out, thats if u like it. If not why not play the games on ya GC? They wont turn out much better quality on the PC
 
Tagrineth

Tagrineth

Dragony thingy
RJARRRPCGP said:
The XBox uses a Pentium III 733 mhz.
Click to expand...

Wrong. P3 733MHz has 256kb 16-way L2 cache.

A Celeron 733MHz has 128kb 8-way L2 cache.

The XCPU is at 733MHz with 128kb 16-way L2 cache...

Thus, a P3/Celeron hybrid.

Edit: That GCN emulation site is hilarious.. look at the computer systems page... it starts out seemingly sensible, but then it goes on with things like

gCubix running Babbage's Analytical Engine, by Warren - let's hear what he's telling us :
Well, it took some time to re-write the code to get gCubix running on the 100% mechanical hardware of Charles Babbage's Analytical Engine, but here it is.
It averages a re-fresh rate of about 1 frame per week, which isn't too bad considering Babbage never finished the engine and this is just the "Mill" section that his son built.
Click to expand...

And running on an ATARI ST, et al...

Some great photoshop work on that site :)
 
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