PS2/PS3 backward compatibility

[Simon82]

Hi,

I was talking in nationals hw forums about the backward hardware compatiblity on board con PS2 and PS3. Some peoples tell that PS2 from a certain version has not got R3000 or other hardware involved in the PS1 games compatibility but (like PSP) there's software code that make use of the central EE processor. What do you know about it? I know that from V14 board EE+GS replaced the 2 chips on one unique soc but what about PS1 part? And what about PS1 compatibility on Playstation3?

Thank

 

[croc hunter2]

Indeed that is true, the PS1 is emulated thru software on the later PS2's and the PS3. The PS3 has a PS2 chipset in it so therefore it's the same as the later PS2s.

Not sure what version the PS1 HW disappeared but it aint there anymore.

 

[taucias]

Indeed that is true, the PS1 is emulated thru software on the later PS2's and the PS3. The PS3 has a PS2 chipset in it so therefore it's the same as the later PS2s.

Not sure what version the PS1 HW disappeared but it aint there anymore.

How is that possible? Does the PS2 use the PS1 chipset for I/O duties (USB control and so on?)

 

[Shifty Geezer]

How is that possible? Does the PS2 use the PS1 chipset for I/O duties (USB control and so on?)

It did.

 

[taucias]

What replaced it then?

 

[mech]

Woah, news to me... got any more info on this?

 

[patsu]

http://www.neogaf.com/forum/showthread.php?t=526722

So over the last week or so the file encryption on the PS2 classics emulator has been completely reverse-engineered. You can now switch the ISO of any PS2 classic with that of any other PS2 game if you have a PS3 with CFW. Compatibility should be pretty high.

It still amazes me that PS3 can emulate PS2 via pure software. Some games probably run like sh*t. Will try it on my PS3 when PS4 is released.

 

[Exophase]

I'm pretty surprised too, although I guess work on emulating everything but the GPU was done a long time ago and probably improved over the years. I shudder at the amount of development effort that had to go into this.

Would absolutely love to learn more details on how it works, although I know that'll probably never happen. I did hear a few things about POPS, Sony's PS1 emulator for PSP where the same injection hacking occurred.

Guessing one SPE each is a reasonable fit for VU1 and VU0 when in micro mode, and perhaps a third for the SPU. R5900 and IOP emulated on the PPE in separate threads, and pray that the code is marginally cache friendly and not branch crazy. Sure, PS2 wouldn't have been very good at those things either but not so much PS3 level. Also avoid emulation strategies that increase RAM footprint at all.. using the PS3's MMU and getting direct access to exceptions vs needing to go through a heavy OS can help a lot. Possibly throw in some HLE of common library versions if such a thing even really existed.

Looks like some games do run poorly or don't run at all but so far the compatibility rate for unofficial titles alone is impressive: http://www.pshomebrew.net/wiki/PS2_Classics_Emulator_Compatibility_List I guess it couldn't have been that low if they were already offering so many games..

 

[dagamer]

I'd love to the see the PS4 emulate the PS2 and stream it to my Vita.

 

[tuna]

I'm pretty surprised too, although I guess work on emulating everything but the GPU was done a long time ago and probably improved over the years. I shudder at the amount of development effort that had to go into this.

Would absolutely love to learn more details on how it works, although I know that'll probably never happen. I did hear a few things about POPS, Sony's PS1 emulator for PSP where the same injection hacking occurred.

Guessing one SPE each is a reasonable fit for VU1 and VU0 when in micro mode, and perhaps a third for the SPU. R5900 and IOP emulated on the PPE in separate threads, and pray that the code is marginally cache friendly and not branch crazy. Sure, PS2 wouldn't have been very good at those things either but not so much PS3 level. Also avoid emulation strategies that increase RAM footprint at all.. using the PS3's MMU and getting direct access to exceptions vs needing to go through a heavy OS can help a lot. Possibly throw in some HLE of common library versions if such a thing even really existed.

Looks like some games do run poorly or don't run at all but so far the compatibility rate for unofficial titles alone is impressive: http://www.pshomebrew.net/wiki/PS2_Classics_Emulator_Compatibility_List I guess it couldn't have been that low if they were already offering so many games..

Sony already had an EE emulator running on the Euro PS3. Now they can emulate the GS as well.

 

[Brad Grenz]

Pure software emulation is how the PS2 Classics have always run. Hackers are just swapping in untested ISO files to see how other games run. Some might work ok, others show glitches, and at this point no one is actually playing all the way through these unsupported games to see if they eventually break or experience performance issues.

 

[Grall]

Now they can emulate the GS as well.

How is the performance of that? GS had extremely impressive rasterization performance for its time.

 

[Exophase]

Sony already had an EE emulator running on the Euro PS3. Now they can emulate the GS as well.

Hence why I said "I guess work on emulating everything but the GPU was done a long time ago."

 

[patsu]

Looks like some games do run poorly or don't run at all but so far the compatibility rate for unofficial titles alone is impressive: http://www.pshomebrew.net/wiki/PS2_Classics_Emulator_Compatibility_List I guess it couldn't have been that low if they were already offering so many games..

Pure software emulation is how the PS2 Classics have always run. Hackers are just swapping in untested ISO files to see how other games run. Some might work ok, others show glitches, and at this point no one is actually playing all the way through these unsupported games to see if they eventually break or experience performance issues.

If it’s like the Internet we all know, the community will come up with a compat list.

 

[Brad Grenz]

They already have, but they're marking everything "playable" even if it glitches and whether or not anyone has played more than ten minutes.

 

[patsu]

Where’s the link ? The good folks will refine the list no doubt.

 

[Brad Grenz]

You quoted it above: http://www.pshomebrew.net/wiki/PS2_Classics_Emulator_Compatibility_List

EDIT: I should say the previous time I was looking at it last night there were fewer tested games and stuff like GT4 and FFXII just had the "playable" label. The more honest version I'm seeing today shows many of the unsupported games have often significant problems.

 

[patsu]

Oh I see, I thought that's the official PS2 Classics game list.

 

[anexanhume]

I'd love to the see the PS4 emulate the PS2 and stream it to my Vita.

I think the prospect of any always on console with severely limited features because of CFW or a laborious update process is enough to deter most into running the stock firmware and buying the classics they do want off of PSN when they're released.

 

[tuna]

Hence why I said "I guess work on emulating everything but the GPU was done a long time ago."

And I told you you were right!