[fpc-pascal] speed of real calculations
M.Santhoff at t-online.de
Wed Oct 18 11:20:01 CEST 2006
Am Mittwoch, den 18.10.2006, 09:54 +0200 schrieb Florian Klaempfl:
> Jonas Maebe wrote:
> > On 18 okt 2006, at 08:31, Marc Santhoff wrote:
> >> is anyone aware of or has done a calculations speed comparison for the
> >> four float types (single, double, extended, comp)?
> > For the x87, the only difference can come from cache misses/hits due to
> > the different sizes they take up in memory, because the x87 performs all
> > calculations using either extended (the default in FPC) or double
> > precision (user-settable).
I read this as "any float calculation is done by using x87 copro". Good
to know, so bigger is better in this case.
The only concern left is the question for other CPUs, but in fact the
main target is x86.
(Note to myself: have a lok at fpc generated assembler and cpu
> You can set it also to single. But these settings affect only division, roots
> and other complex operations.
Divisions do make a difference for me. How can this setting be made, is
there a compiler sitch involved or some symbol to define?
Thanks so far,
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