There are more than "everything gets turned into uops" out-of-order execution engines - scoreboarding, for example, provides most of benefits for much less energy cost. >Everything gets turned into uops, this instruction can emit more than one. >"load multiple" from PC (which is exposed to programmer in quite peculiar way) But the very fact that you have to check before issuing operation make things more complex than they can be. You cannot do that - pull as much as possible in one go, - for case page boundary is crossed. >You do a check for the full range before the access, because for best performance you would want to pull in as much as possible in one go anyway. I designed a MIPS core prototype and I was done in single week with all arithmetic and memory access commands and spent three weeks designing, implementing and debugging branch handling, due to branch delay slot "feature". The number of corner cases of old architectures (MIPS, or SPARC) is staggering. The number of corner cases is much smaller. >If that is "hard", I would hate to see what you think of things like cache coherency across cores.Ĭache coherence across cores is easy.
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