On 2014-02-17, at 10:36, Ted MacNEIL wrote:
I have to ask: Why they big concern over a few instructions? Optimisation of a few is not worth the effort these days.
LOL. If Binyamin's question wasn't worth asking, then IBM would never have recently introduced the STOC instruction that John McKown so kindly reminded us about. (Wish we could use instructions like that in other than our JIT-compiled Java code...)
If most simple instructions run in roughly one cycle (with the "wind" at their back i.e., no interlocks or other delays), an L1 memory access is zero cycles, and an uncached memory access is roughly 1000 cycles, then it makes perfect sense for professional programmers to want to understand how they might avoid having even a small code fragment run three orders of magnitude slower. Add enough of them up and it can make a big difference.
If professionals never ask questions, they'll never know the answers when they need them.
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