🚀 go-pugleaf

Chris Ebenezer <chriseb@nortelnetworks.com> wrote:
[...]
>I notice they say that "The core of the I/O processor is the
>CPU of the current Playstation", so i guess its a R3000
>based core ?

Yup. Details are at http://www.lsilogic.com

>Still, what do they mean by the term I/O processor, in this context ?

Glorified DMA controller, AFAIK.

By making it a programmable CPU, they get all sorts of benefits.
Some uses might be:
* disc effects, eg: FAT look-ups, transparent decompression,
    scatter-gather (to reduce seek times), intelligent caching...
* compression/encryption of (FireWire) network signals.
* asynchronous saving of game data.
* interpolation of controller/network inputs.
* generating random numbers (which is pretty time consuming if
    you need a lot of them).
* running game logic, leaving all 6 GFLOPS for geometry...

Basically, if it's available to program, then it'll be used for any
low-priority background tasks that happen to be lying around
waiting for CPU time...

>Surely, it means that this processor also has to be used as the main
>processor for using older games ?

Looks that way - the lower clock speed mode certainly implies that.

Given the power of the CPU, however, it could certainly emulate
PSX1 games. Their stated approach, however, is to provide 100%
compatability (ie: no better or worse). Maybe they'll release a
software emulator later, one that makes use of higher-res graphics
and fancy effects when playing (most) PSX1 games...

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Russ