PS2 Emulation Patent Reveals Sony's Difficulties News

Let's admit it PS2 emulation is something that you'll probably never use, but at the same time there's still a desire to have it.  If Sony hadn't have introduced backwards compatibility in the first place and originally mocking fun of Microsoft's efforts with the 360, we probably would never have bothered.

Still it's been a number of years since Sony decided to strip away the PS2 hardware featured in the original PS3 models as a cost-cutting measure, and yet the feature is still one of the most desired from PS3 owners and potential adopters.  Thankfully, it appears that backwards compatibility could finally be on the way if a recent patent application is anything to go by, spotted by Silconera.

A patent that TVG has discovered, which appears to be different from that sourced by Siliconera, is dated from 2007, suggesting Sony has been working on this for a considerable amount of time.

Of course, software emulation is nothing new, but it does typically bring a high overhead, particularly when you're dealing with such specialised hardware such as the PS2's Emotion Engine.

Further details from the patent, however, reveal the difficulties that Sony face when trying to emulate the PS2's 128-bit CPU on something as radically different as the PS3's CELL processor.

"If the host system is based on larger sized registers, this is not a problem as it is relatively straightforward to emulate 128-bit registers with a processor having larger-sized registers. However, if the PlayStation(r)2 is emulated by a cell-processor based host system (such as the PlaySta- tion(r)3), a problem arises."

"The cell processors are a type of parallel processor. The basic configuration of a cell processor includes a "Power Processor Element" ("PPE") (sometimes called "Processing Element", or "PE"), and multiple "Synergistic Processing Elements" ("SPE"). The PPEs and SPEs are linked together by an internal high speed bus dubbed "Element Interconnect Bus" ("EIB")."

"Cell processors are designed to be scalable for use in applications ranging from the hand held devices to main frame computers. The PPE is the main processor for emulation the PS2 EE. Unfortunately, the PPE uses 64-bit registers, which are smaller than the 128-bit EE CPU registers. [0010] Thus, there is a need in the art, for emulating a target system on a host system having smaller sized registers than the target system."

The details contained within the patent appear to be the solution to the problem.  So, although it's not exactly official confirmation that backwards compatibility is on the horizon, it does at least clarify why it hasn't appeared so far and suggests Sony is attempting to find the answer.