Would 64bit benefit PCSX2 like it did with Dolphin?

[Dr_Hycodan]

64 bit Dolphin is about 40-50% faster than 32 bit Dolphin (no longer supported). Can we expect the same improvement with pcsx2 moving to 64 bit?

[jesalvein]

Afaik, nom.
There will be some improvements, but very few

[dogen]

The last I heard on the subject was no, not really.

And dolphin didn't get a 40-50% boost from going 64 bit. It got most of that from a feature(I believe it was fastmem) that wasn't supported on the 32 bit version.

[n1dminhd]

PCSX 2 with Fastmen is about 40-50% faster than PCSX 2 ?

[ssakash]

there might be some increase in performance on 64 bit builds but there really aren't much advantages which might spark interest on X64 bit support.

The EE uses little to no 64 bit Instruction sets whereas, It mostly uses 128 bit (SSE) and 32 bit instruction sets. also, the 64 bit instruction might be slow in certain scenarios.

overall, that would lead developers to maintain two different versions and would be a problem to maintain the project. there really aren't much benefits for PCSX2 on a 64 bit platform (considering the trouble of writing codes for 64 bit support) , eventually it would lead to dropping a certain version and concentrating on a specific one which is our current approach by using the 32 bit builds.

[refraction]

Without sounding like a retard, what is fastmem and what does it do? Is it just a faster way of addressing memory in assembly? because PCSX2 has done that for years.

[Blyss Sarania]

Without sounding like a retard, what is fastmem and what does it do? Is it just a faster way of addressing memory in assembly? because PCSX2 has done that for years.

Not sure exactly what it does, but in Dolphin it only existed in their 64 bit branch. That's why 64 bit was so much faster on Dolphin. However, it wasn't impossible to port it back to 32 bit, they just decided it wasn't worth the trouble to do it, and it's one reason they dropped 32 bit.

I tried to find any more info via google just now and came up short.

[refraction]

I tried to find any more info via google just now and came up short.

Same for me. Hopefully one of the lingering dolphin devs can shed some light on this, or provide a link

But yes I think the decision was to move to 64bit so the focus was made there, of course 32bit code will probably be different, but as they were dropping it there would be no point.

Aside from the memory restriction being lifted, 64bit doesn't serve much of a benefit for the amount of work involved to port the program to it. But any games on the PS2 needing more than 2gb of ram to emulate means there's something very wrong. Games like the snowblind ones are amongst these because they keep making hundreds of small textures which of course eats memory, which is why they need more than 2gb. If that was fixed you probably wouldn't need more than 1gb

[Blyss Sarania]

Just cuz I'm curious:

How do we handle > 32 bit stuff that EE can do? Like 64 bit integer ops? And 128 bit registers? I mean I can think of ways to do it, I'm just curious how we actually do.

[refraction]

Just cuz I'm curious:

How do we handle > 32 bit stuff that EE can do? Like 64 bit integer ops? And 128 bit registers? I mean I can think of ways to do it, I'm just curious how we actually do.

The PS2 was a victim of the "bit wars" just like every other console (im looking at you '64bit' Jaguar!) the PS2 was very much 32bit, but it had 128bit registers, in much the same way as SSE on x86 processors, nothing really used 64bit ops like that, if they do, the upper 32bits is pretty much always just the sign from the top of the lower 32bits repeated throughout, for example
...Upper...........Lower
0xFFFFFFFF 0x80001000
0x0000000 0x00001000