The myth of software PS2 emulation on PS3

[BRIK]

I have a second generation fat PS3 and that doesn't support PS2 at all. You can play PS1 games though.

[Niode]

How many times does this need to be stated?

IT IS NOT EMULATION. The launch units in US and JP regions have the Graphics Synthesis chip and the Emotion Engine on the motherboard. In Europe/PAL we got just the Graphics Synthesis chip and the rest is software (IE it takes the syscalls from PS2 software and dynamically recompiles them to the instructions that the CELL understands). Then they removed it altogether in the subsequent models in Europe. The US got the 80GB version which was essentially the same SKU as the Europe/PAL launch model (G.S. Chip and software) except with a bigger HDD.

I honestly can't see emulation ever happening on the PS3. It's just not powerful enough. Regardless of how optimised PCSX2 gets. I seriously don't understand how the PS3 gets this reputation as being this amazing powerful behemoth. On paper it appears faster than the Xbox 360 but the 360 has time and time again wiped the floor with it in real world scenarios.

[J T]

PCSX2 is the best available PS2 emulator at the moment and it's hard to run on a modern computer with good specs, so I doubt the PS3 will ever be able to run it. Maybe the next generation of consoles will be able to run a PS2 emulator.

[Limewater]

It's just not powerful enough. Regardless of how optimised PCSX2 gets.

But PCSX2 isn't written specifically for the hardware in the PS3. If someone targeted it specifically for the hardware in question, I wouldn't be surprised if perfect PS2 emulation on a PS3 was possible. There just isn't much of a payoff to motivate development.

[MrPopo]

It's just not powerful enough. Regardless of how optimised PCSX2 gets.

But PCSX2 isn't written specifically for the hardware in the PS3. If someone targeted it specifically for the hardware in question, I wouldn't be surprised if perfect PS2 emulation on a PS3 was possible. There just isn't much of a payoff to motivate development.

The thing is that on the PC end it's already pretty well optimized for the PC. Sure, if you really dug deep you could choose a specific model processor and recode major parts in assembly taking advantage of some obscure tricks in that particular ISA but you're not going to get a significant speedup from it. Code is too complex nowadays, and we've gotten pretty damn clever at writing compilers that do those kinds of optimizations so we don't have to. If you fully recoded PCSX2 in assembly for a particular chip you might get a 10% speed boost, and you'll be finished once Nintendo's 20th generation console is launched and people remember the PS2 the same way people remember the Genesis today.

[Niode]

It's just not powerful enough. Regardless of how optimised PCSX2 gets.

But PCSX2 isn't written specifically for the hardware in the PS3. If someone targeted it specifically for the hardware in question, I wouldn't be surprised if perfect PS2 emulation on a PS3 was possible. There just isn't much of a payoff to motivate development.

The thing is that on the PC end it's already pretty well optimized for the PC. Sure, if you really dug deep you could choose a specific model processor and recode major parts in assembly taking advantage of some obscure tricks in that particular ISA but you're not going to get a significant speedup from it. Code is too complex nowadays, and we've gotten pretty damn clever at writing compilers that do those kinds of optimizations so we don't have to. If you fully recoded PCSX2 in assembly for a particular chip you might get a 10% speed boost, and you'll be finished once Nintendo's 20th generation console is launched and people remember the PS2 the same way people remember the Genesis today.

Couldn't have said it better myself.

[Limewater]

The thing is that on the PC end it's already pretty well optimized for the PC.

That's a whole different beast than a PS3, though. That's the difference between a general purpose computer and an embedded system.

Sure, if you really dug deep you could choose a specific model processor and recode major parts in assembly taking advantage of some obscure tricks in that particular ISA but you're not going to get a significant speedup from it. Code is too complex nowadays, and we've gotten pretty damn clever at writing compilers that do those kinds of optimizations so we don't have to.

You shouldn't be thinking code. You should be thinking hardware. To code a fast PS2 emulator on a PS3, you would need to look specifically at what each part of the PS2 does and find the closest analog in the PS3 hardware and make sure that part of the machine is performing that task. For one thing, the PS3 should be able to dedicate five cores completely to the task of PS2 emulation without interruption from the operating system. This is a huge advantage over trying to emulate on the PC running a non-real-time OS.

And, for what it's worth, I've seen two pieces of code compiled with the same compiler and running on the same hardware to perform the same task where the runtime difference between the two was a couple of orders of magnitude. Efficient code is still worth writing.

If you fully recoded PCSX2 in assembly for a particular chip you might get a 10% speed boost, and you'll be finished once Nintendo's 20th generation console is launched and people remember the PS2 the same way people remember the Genesis today.

I'm pretty sure the payoff would be a lot better than 10%. But again, I would be surprised if anyone actually wrote a great PS2 emulator for the PS3. There's not really a strong motivation to do so among the folks with the documentation necessary to make it doable with a reasonable amount of effort.

[MrPopo]

The thing is that on the PC end it's already pretty well optimized for the PC.

That's a whole different beast than a PS3, though. That's the difference between a general purpose computer and an embedded system.

That argument worked back in the days of CISC chips. You had crazy interesting instructions that were hyper optimized but only worked for certain tasks. That's not the case anymore. The ISA of the PS3 looks very similar to the PC. The big difference between coding for the PC vs. coding for the PS3 is on your RAM supply. Which makes it MORE difficult to make a working PS2 emulator, since on a PC you can just throw hardware at the problem.

[wip3outguy7]

I have always had a theory that the only reason we received backwards compatibility for PS1 games on the PS2 was because Sony knew the launch lineup for the PS2 was going to be pretty poor. They also knew that the coming months would yield few games. Building in PS1 compatibility would mean fewer PS2's collecting dust. People may not have had any PS2 games to play, but the systems would receive plenty of use as Playstation 1s and DVD players.

I think they went with the same concept for the PS3. However, this time around they decided to remove PS2 backwards compatibility when enough of the market had picked up the system. I believe another deciding factor in this was Sony's belief that the PS3's library was strong enough to support the system on its own. I don't think they ever intended to keep PS2 compatibility around for the long term.

So with those ideals in mind - even if technologically possible, I don't think PS2 compatibility is coming back to the Playstation 3.

[isiolia]

One factor to keep in mind with the PS2 playing PSX games is that Sony worked the PSX's CPU into the PS2's hardware design (it's the IO controller). So it had a reason to be there above and beyond playing PSX games. That wasn't the case, AFAIK, with the PS2's CPU/GPU in the PS3.