| Groucho said: You should really avoid commenting on this, since you have, quite obviously from this comment, never worked on a PS3, or at least never with the SPUs. I can say with authority that the italicized parts of the comment above is pure BS, and the sources you got it from don't know what the hell they are talking about. The SPUs *are* general purpose cores, with a lot of extra logic devoted to vector mathematics. They lack the supporting memory architecture to do things in the same manner as the PPU, but that doesn't stop them from being able to do it. Being an independant core doesn't require that you be able to address main memory directly -- the only requirement is that the processor be able to run concurrently with other cores. The SPUs can, and frankly they can run general purpose code, that doesn't involve accessing large tracts of memory (which is a big deal), just as fast, or in some cases faster, than the 2 hardware PPU threads can. The bolded part of your comment is absolutely correct, however. At least you got that right -- or your source did. The only reason any newbie engineer wannabe could possibly claim that the SPUs are "not independant cores" is due to the fact that they can only address their 256K local memory (not a "cache" as some have called it), and must stream data from main memory in/out. The truth is, however, they can do this independantly of the PPU. Thus *drum roll* they are independant cores. They are NOT coprocessors, as you seem to be implying, as that's the word used to describe a "dependant processor" which isn't actually capable of independant operation. The SPUs are -- thus, they are independant cores. I know you aren't going to be able to say to someone who doubts this fact "Groucho said that's not true", but I can tell you that, if you understand that the SPUs are independant cores, you will be correct, and anyone who says otherwise is... well, ignorant, and full of ****. Please have faith that some authorities do surf here, and please stop peddling this kind of hogwash.
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1. I have never programmed the PS3... that is absolutely correct. I am simply repeating information I have gathered from others who have programmed the PS3, so I'm not going to try to argue with someone of your truly dizzying intellect.
2. I never claimed that the SPUs were incapable of running generalized code... just that their primary function and design were for other tasks, and that this could make them less effective in ways than a general purpose core. You admitted as much in your response.
3. Considering that I said the SPUs were like DSPs or bit-blitters on steriods, it's difficult to imagine you're arguing that they're instead cores with lots of vector processing. You DO realize that DSPs and bit-blitters specialize in vector processing, right?
3. I never said the SPEs were co-processors. And for your information, the Amiga "co-processors" (agnes, denise, buster, etc.) were capable of operating independently of the 68k CPU (in fact, Jay Miner architected the Amiga hardware so the co-processors and CPU operated on alternate bus cycles so they would have less contention when accessing memory). And yes, I did programming on the Amiga. And yes, I've programmed for 28 years--everything from satellite communications to kernel work to embedded systems--so I'm not a "newbie engineer wannabe".
4. Your post actually does point out an area where my post was weak... I could have described more clearly what I meant when I said programming the SPUs can be heavy lifting. It's not because they can't run general purpose code, it's because they're designed primarily to handle vector processing, and that's what many of the devs are trying to use them for, i.e. - to do what the PPU isn't as good at. Their not designed to be general purpose cores... their primary function is to ASSIST the core with what it doesn't do well.
I've had disagreements with MikeB on technical elements of the PS3, but I don't remember him making them into personal attacks as you have... "above is pure BS", "You should really avoid commenting on this", "At least you got that right -- or your source did", "any newbie engineer wannabe", "ignorant, and full of ****", "please stop peddling this kind of hogwash". I don't know why you're venting your spleen on me, because I'm not the only person on VGCharts who believes IBM's technical literature when they refer to the Synergistic Processing Units as vector processors.
Had you taken a different tone in your response, I would have gratefully accepted what you said and shown an interest in learning more about how the PS3 and Cell really work (I've learned a few things from MikeB and others), but now I'm not really interested in listening to what you have to say on the subject.
