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From: dewar@merv.cs.nyu.edu (Robert Dewar)
Subject: Re: fixed point vs floating point
Date: 1997/11/25
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Date: 1997-11-25T00:00:00+00:00
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John says

<<Table lookup has been an important speed optimization for many years,
but does it still work well on newer processors? My experience is that
I don't get the speed improvements that I expect, probably due to the
increasing penalty for cache misses on faster processors. The trend
seems to be that branch-free pipelined code will run faster than table
lookups. Have optimizing compilers kept up with the shifting
tradeoffs?
>>

Indeed with the modern progression of ever increasing values for the
ratio (processor-speed / main-memory-speed), table lookup can often
be quite unattractive. On a really fast processor a second level cache
miss is enough time to compute LOTS of floating-point stuff.

I am not sure this particular point is an issue for optimiztion, but
the general question is that the study and implementation of optimization
techniques these days is *VERY* much concerned with cache performance!