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IBM-Sony-Toshiba Reveal New Cell Processor Details
BBCWatcher writes "The three main partners in the Cell Processor initiative announced technical details of the new architecture. IBM's documents are particularly revealing. There's much more information on how developers, including open source developers, can access the SPUs (Synergistic Processor Units). As reported earlier, Sony will put the Cell into every Playstation 3 game machine, due early next year. And yes, Cell runs Linux."
Not just buzzword compliant, but confusing as hell for those of us who have been in the know for a while.
To me, SPU always made me think "Scalar Processing unit", while PPE made me think "Parallel Processing Element".
Of course that's exactly backwards.
That, and I choke on words like "synergistic" because they peg my bullshiat-o-meter way off in the red.
In my opinion one of the coolest features of this architecture are the way the reciprocal estimate and reciprocal square root estimate instructions work.
In a single cycle you get 13 good bits of precision -- with the low order bits filled with information to be used by the floating point interpolate instruction.
You can get a full precision (32 bit ieee float) reciprocal in about 6 cycles, and a 1/sqrt in 7 or so. Oh, and that's 4 results in that time. Averaging 1.5 cycles per FP divide, and slightly more for sqrt. times 7, times 3.2 billion per second, and the bandwidth to feed it.
That's several orders of magnitide faster that you could do with any x86 part out there.
Ian Ameline