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you mention ps2 - is the ps3 similar? (although its powerpc - there are 7 cores to use - so is it still as tricky?)
by michaelneale 18y ago
you mention ps2 - is the ps3 similar? (although its powerpc - there are 7 cores to use - so is it still as tricky?)
- jaydub 18y agothe PS3 uses the Cell processor which is also tricky to program
- DarkShikari 18y agoThe Cell is a whole different type of nightmare, with various interesting properties: 1. Bitshifts by variable amounts take ~7 clocks each on the main PPU. 2. The SPUs have no cache whatsoever; all caching has to be done explicitly, and all memory access is DMA'd. 3. The SPUs do scalar math no faster than SIMD (in fact, from what I know, scalar math is just calling an SIMD function on a single value). 4. There is no instruction reordering on SPUs, and everything has to be synced exactly for max performance (certain instructions run on odd clock cycles, others on even cycles). 5. The SPUs are not Altivec chips. The SPU SIMD instruction set is similar to Altivec, but more versatile. Of course, this means you can't just run existing Altivec code on them. 6. Overall, the integer SIMD on SPUs is much slower than that on modern Intel processors. Not sure about float, as I have no experience in that arena.
- michaelneale 18y agoWow that sounds like a world of fun. For some definition of fun. The one that shocked me: "1. Bitshifts by variable amounts take ~7 clocks each on the main PPU" If you didn't know that, that could really bite hard.