Re: using linux instead of osf

Scott Manley (spm@star.arm.ac.uk)
Wed, 27 Nov 1996 09:10:11 +0000

OK correct me if I'm wrong (and I could well be) but surely the single
precision sin algorithm should be twice as fast for the simple reason that
the number of operations required to converge to the accuracy required will be
fewer, and therefore fewer CPU cycles are used.

When I implemented similar routines in 68000 assembly this was certainly the
case, can anyone tell me what kind of algorithm the trigonometric functions
use (since that's where most of my experience lies). Is there some algorithm
which is independent of the precision?

> So, whether single-precision buys you execution time or not depends
> very much on what you're doing. In a naive timing loop measuring
> sinf() performance you'd not expect to see any difference since
> everything will be cached and sinf() uses no fp divisions.
>
Indeed this was the sort of quick hack I used, I wanted something heavily
dependant on trig functions.

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