4 ms·

I'm not sure. If that were the case why wouldn't intel expose a native, better fit to uops instruction set in addition to the legacy, difficult to decode one an

• umanwizard 7y ago
  My guess is (1) inertia, and (2) not wanting to commit to a specific instruction set because they tweak the internal μop set with every release. And (3), this would add complexity, because, even though one is much simpler, now you need two completely separate decoding pipelines and mechanisms for switching between them.
  • makapuf 7y ago
    Can't argue with 1. For 2 it's still an instruction set separate from uops so you might not be as sensitive to changes you still get a level of indirection. For 3 .. it depends. You might gain in power if you use the newer one more and you might as well make the older one simpler to achieve 90% of speed maybe. But maybe the decoding of instructions that counts is not that expensive compared to OOO branch predictors and 512 bits ALUs