smallflyingtaco said:
I have yet to see anything on POWER8 so your ahead of me there. Even if MS is using a derivative set of instructions it does not mean it will not be compatible with the POWER7, as we would have to know if they have more instructions or a subset of the POWER7 instruction set. The same with Broadway. If they have added instructions then it would rule out an off the shelf solution without some middleware to deal with it for backwards compatibility. As for developer ease the instruction set differences between them should be easy to hide from developers by the compiler as they will not change a lot in architecture by replacing the CPU with a standard IBM CPU. The CELL is not going to be simple in its current form. That the various cores are so different that you have to know what goes where. Getting around that will not be easy as some of the elements of it that are so powerful are tied to that. The SIMD SPEs let it do a lot of certain types of work but that they are SIMD while the the PPE is a fused multiply-add processor, it can solve 2 y=ax+b type problems per cycle, keeps this complex. Removing the SPEs would hurt it in graphics programming, and in scientific programming, but shifting the PPE would make life harder for regular programming type needs. Probably from a development standpoint doing something like is done on Roadrunner and adding a completely secondary powerful general purpose processor would make life easiest. Cost I have no clue on. The problem of dealing with these makes life hard on the console makers as they need to sell a lot to get scale based discounts. The easiest solution would be for them to try and do what Sony aimed to do, use a processor that was supposed to be used in a lot of other things. The problem though is consoles are frozen in time while everything else moves on and you might be wrong to start with. If they all used the same processor they could perhaps help this but that would probably hurt their marketing and encourage even more multiplatforming.
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it has more to due with instruction sets being removed, braodway uses instruction sets not in latter chips, the little endian(i think thats the right spelling) which has not been in powerpc since power5. the power5 that the 360 uses is highly modified, and uses added features not found in power5 main line chips, to boost loating points and what not. i agree with you on the cell, it will be hard to streamline any upgrade, but if anyone could do it ibm could.
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