PS3 PS2 emulation

[Betanumerical]

The PS2 has 48GB/s bandwidth to it's frame buffer. Emulating that on a PS3 is impossible. Working around it means collapsing multipass algorithims into shaders. I could see hand coding solutions for a few games, but a general solution is just not in the cards.

Well bandwidth is not really a issue (as discussed in the other thread). That is because.

1. The RSX supports texture compression which the GS never did, this frees up bandwidth.

2. Splitting the objects / textures into both pools of ram nets 48GB/s of bandwidth, strange aye.

 

[dukajoe]

Well, I'm not a developer, but it seems like they could set up some sort of virtualization with that many cores, or have some compressing/decompressing or interpreting ect. I guess I thought that the many cores would make it better at emulating specifically.
But, now I don't know what the compatibility percentage is for 40, 80 gb skus, but say you take that remaining percentage, hand code patches that you d/l when you insert the game, and then you have 100 percent compatibility, right? That's probability what they are doing right now though....
I don't know about the being better than ps2 graphics ect--I was just thinking back to bleem days ect. It seems though, like everything with the ps3, you'll have to think of everything in a different way (heavy multithread), or you wont get optimized results.

 

[Squeak]

How about bypassing the RSX entirely, and doing the GS emu on the Cell as well? There is enough memory on there to make it feasible i think.
Two or three SPUs to emulate the EE and the rest for emulating the GS and PPE for orchestrating the whole thing...

 

[DieH@rd]

IMO, they should make game specific emulator, and release that game over PSN. Even one game per month would be enough.

 

[I.S.T.]

PS2 didn't emulate the PS1, it included all the required hardware from the PS1.

No, it didn't. There is no PS1 GPU chip in the PS2. IIRC, its' functions are either mapped onto the GS, or emulated on it.

I think the SPU is handled by mapping the instructions onto the SPU2.

 

[Fafalada]

How about bypassing the RSX entirely, and doing the GS emu on the Cell as well? There is enough memory on there to make it feasible i think.

Rasterizing ~1Gpixels/sec with bilinear filtering and ZBuffer is a tall order for even SPEs.
I'd say RSX has a far better chance - dynamic reordering of display lists is no different from JIT for the CPUs, reinterpret some parts to give huge boosts to the native hw. All they really need to do is find a way to sort by expensive state changes (texture flushes, render target switches) without breaking rendering results, and speed will never be an issue.

Yea of course there's still compatibility issues to take care of with all the funny addressing modes and what not, but that'll have to be solved in any software solution anyway.
To be honest I wouldn't be surprised if the biggest problem is emulating paletted memory addressing reliably, as opposed to all the other stuff that gets thrown about. Sony really should kick NVidia on the head over this one, native Clut support would have benefited PS3 software as well.

IIRC, its' functions are either mapped onto the GS, or emulated on it.

That part is true - EE translates PS1 display commands for GS. Afaik the only hw extension was GS supporting 8bit color screen mode.
And as mentioned, in latest PS2 models, the PS1 CPU is emulated as well.