xbone backward compatibility!

[monstercameron]

So it seems the jaguar cores will be emulating the ppc cores!
link soon.

 

[Dahak]

http://arstechnica.com/gaming/2015/06/xbox-360-backwards-compatibility-coming-to-xbox-one/

Starting later this year, the company's newest console, the Xbox One, will support a limited number of older Xbox 360 games.

 

[ShintaiDK]

Limited being the key word. And it may be cloud powered like Sonys.

 

[monstercameron]

Limited being the key word. And it may be cloud powered like Sonys.

nope and no, it is native, or so they claimed on stage.

 

[Erenhardt]

It could be possible if only consoles had an amd apu in them...

 

[Dahak]

nope and no, it is native, or so they claimed on stage.

well according to the article, its not native

The limited compatibility and need to download even those games that are owned on disc suggests to us that some mix of recompilation and emulation is in use.

Where i see native being, you put the disc in and it works

 

[monstercameron]

well according to the article, its not native



Where i see native being, you put the disc in and it works

hmmm interesting.

 

[ericloewe]

So it seems the jaguar cores will be emulating the ppc cores!
link soon.

Not particularly impressive.
Dolphin and PCSX2 have been recompiling PowerPC and MIPS (respectively) on x86 for a long time.

The real problem is keeping everything in sync when running stuff in parallel. That's made much easier when the emulating architecture also behaves more or less like the emulated one (shared memory pool, eDRAM, separate CPU+GPU, no funky ASICs that games directly interface with...).

Many tasks are also abstracted away, making compatibility trivial (saves/disk management, networking, input, online services...).

If you take a look at emulator development, a big part of the challenge is figuring out what the hardware's behavior is - not a problem when you designed it.

It will be impressive if they can eventually faithfully emulate everything.

 

[exar333]

Not particularly impressive.
Dolphin and PCSX2 have been recompiling PowerPC and MIPS (respectively) on x86 for a long time.

The real problem is keeping everything in sync when running stuff in parallel. That's made much easier when the emulating architecture also behaves more or less like the emulated one (shared memory pool, eDRAM, separate CPU+GPU, no funky ASICs that games directly interface with...).

Many tasks are also abstracted away, making compatibility trivial (saves/disk management, networking, input, online services...).

If you take a look at emulator development, a big part of the challenge is figuring out what the hardware's behavior is - not a problem when you designed it.

It will be impressive if they can eventually faithfully emulate everything.

Offering this on a console would be pretty great though. For most users, that would be a much more palatable emulation tool vs. on a computer. It is a great selling point on the console too, especially for those still holding-on to older consoles that haven't upgraded yet. Nice value-add.

 

[Sonikku]

The Xbone could do Backwards compatibility today if it wanted to. No reason at all why I should have to drag out a whole extra massive console and deal with a whole other set of hookups and power supply just to play my copy of Panzer Dragoon Orta in 1080p and the like.

 

[Cogman]

Not particularly impressive.
Dolphin and PCSX2 have been recompiling PowerPC and MIPS (respectively) on x86 for a long time.

The real problem is keeping everything in sync when running stuff in parallel. That's made much easier when the emulating architecture also behaves more or less like the emulated one (shared memory pool, eDRAM, separate CPU+GPU, no funky ASICs that games directly interface with...).

Many tasks are also abstracted away, making compatibility trivial (saves/disk management, networking, input, online services...).

If you take a look at emulator development, a big part of the challenge is figuring out what the hardware's behavior is - not a problem when you designed it.

It will be impressive if they can eventually faithfully emulate everything.

Eh? No I think a significant problem, beyond faithful representation, is that severe performance degradation that is inherent with switching uarchs. PCSX2 is actually a really good example of this. Back in the day, you needed at least a Core 2 duo to have any semblance of playability. The original PS2 CPU operated at 300MHz and was built in 2000, predating Athlon XP cpus.

 

[Cogman]

The Xbone could do Backwards compatibility today if it wanted to. No reason at all why I should have to drag out a whole extra massive console and deal with a whole other set of hookups and power supply just to play my copy of Panzer Dragoon Orta in 1080p and the like.

Cross platform compatibility isn't easy. When developers have poured their heart and soul using every dirty undocumented trick in the book to get a game to work on a console, you can bet there is going to be a lot of nasty surprises for the guys trying to get that game into a playable state on a completely different architecture.

Emulation isn't easy.

 

[NTMBK]

The XBox 360 CPU had about a gajillion vector registers, emulating that on Jaguar cores would be rather impressive. I suspect it's using recompiled binaries.

 

[Sonikku]

Cross platform compatibility isn't easy. When developers have poured their heart and soul using every dirty undocumented trick in the book to get a game to work on a console, you can bet there is going to be a lot of nasty surprises for the guys trying to get that game into a playable state on a completely different architecture.

Emulation isn't easy.

Yeah.

So what's so hard about x86 ---> x86?

Everyone's so choked up about getting their 360 games working on the current box that they forgot that Microsoft made a whole other console before that with hundreds of games. I'll say it again. Why can't I play my Shenmue 2/Panzer Dragoon Orta/Jade Empire and the like on the one? What's the big flippin' deal?

 

[Phynaz]

Different GPU

 

[zebrax2]

I'm quite surprised by this move. This is a bit counter intuitive to the recent trend of remakes. I guess this is Microsoft trying really hard to entice away potential buyers from the PS4.

 

[iSkylaker]

The game they showcased is old, one of their firsts and for only few seconds, maybe just me but I somewhat noticed it not playing well. I;m curious to see how this will play out or what they did to achieve the emulation.
After all they must have source code of their own console, I guess it give them an advantage over those 3rd party who make emulator for x86?
https://www.youtube.com/watch?v=Jijn3KOPs5I

 

[nenforcer]

Different GPU

This exactly, Direct X is backwards compatible on the PC for the most part (7, 8, 9, 10, 11) but each console generation (XBOX, XBOX 360, XBOX One) has its own specific DX variant tied to that generation's GPU (Geforce 3, ATI XENOS, AMD Durango).

 

[iSkylaker]

Well, as I expected games that barely put the machine to work
http://www.xbox.com/en-US/xbox-one/backward-compatibility/available-games

 

[Exophase]

Not particularly impressive.
Dolphin and PCSX2 have been recompiling PowerPC and MIPS (respectively) on x86 for a long time.

There are giant differences between the processors in PS2, Gamecube/Wii and XBox 360. ~1.8GHz Jaguar cores can't handle PS2 and Gamecube emulation that well anyway.

 

[SPBHM]

Well, as I expected games that barely put the machine to work
http://www.xbox.com/en-US/xbox-one/backward-compatibility/available-games

"Mass Effect"

this game have performance problems on the Xbox 360 native hardware, so it's a challenging game, even the PS3 couldn't run a traditional port of it well enough and they had to use a new engine years later to make it viable, I think

There are giant differences between the processors in PS2, Gamecube/Wii and XBox 360. ~1.8GHz Jaguar cores can't handle PS2 and Gamecube emulation that well anyway.

yes, 1.8GHz Jaguar trying to emulate PS2 on the PC using PCSX2 is going to be a disaster, you need a lot more than that...

but obviously MS managed to make the tri core PPC 3.2GHz stuff run well on their Jaguar CPU,
perhaps if sony tried to emulate the PS2 on the PS4 (1.6GHz Jaguar) they would achieve much better results than the PCSX2 team.

 

[NTMBK]

yes, 1.8GHz Jaguar trying to emulate PS2 on the PC using PCSX2 is going to be a disaster, you need a lot more than that...

but obviously MS managed to make the tri core PPC 3.2GHz stuff run well on their Jaguar CPU

To be fair, they are probably dedicating two Jaguar cores for each PPC core- the 360 had SMT, meaning each core ran two threads. Splitting those two threads across two x86 cores would be the obvious first step.

 

[therealnickdanger]

Let's see some Xbox One 1 First Xbox games! Emulating that should be a snap as it is already X86/D3D based.

At the press conference, they said NATIVE explicitly more than once. If anything, it's identical to the method employed on the 360, where it downloads profiles for the games being emulated. Either way, whether it plays it off the disc directly or downloads a modified version that plays the same (hence the need for a 1TB HDD), it's still valuable and something they should have focused on at launch.

 

[MiddleOfTheRoad]

There are giant differences between the processors in PS2, Gamecube/Wii and XBox 360. ~1.8GHz Jaguar cores can't handle PS2 and Gamecube emulation that well anyway.

I would disagree.

Emulating standard definition games from the Gamecube shouldn't be an issue -- if the Xbox One can emulate high definition Xbox 360 games. Also keep in mind -- Gamecube and Xbox 360 were both PowerPC based CPU's..... (And Gamecube had ATi/AMD GPU's as well).....

So one would think Gamecube emulation would be relatively straightforward on the Xbox One if the 360 could be done. There is no doubt in my mind that a Xbox One has more than enough processing power to emulate a standard definition-only 2001 era game console.

 

[Blitzvogel]

To be fair, they are probably dedicating two Jaguar cores for each PPC core- the 360 had SMT, meaning each core ran two threads. Splitting those two threads across two x86 cores would be the obvious first step.

That's what I was thinking. Though I wonder if there would be issues with running recompiled Altivec code across even two Jaguar cores when they are only running at 1.75 GHz. I'm sure there are some 360 games that kept the VMX units constantly fed. The other issue is the eDRAM present in the 360 which was capable of 256 GB/s, vs the eSRAM in the Xbone which is capable of just over 109 GB/s and combined with the main RAM is still below 200 GB/s.