[squeak-dev] Re: floats

Hans-Martin Mosner hmm at heeg.de
Sun Mar 15 19:43:01 UTC 2009


nicolas cellier schrieb:
> Hans,
> Tagging/untagging could be very fast! See my other post
>
> 1) UnTagging a double= No op
> 2) Tagging a double= a isnan test (so as to have a representable nan
> in Smalltalk)
> 3) This trick does not had any extra cost to tagging/untagging of
> other oops
That's true for a 64-bit processor, and on such hardware I see the
advantages of this scheme.
For 32-bit hardware, it won't work.
Hopefully we'll all have suitable hardware in the near future...
But for example, I'm running 32-bit linux here on my 64-bit AMD
processor just because the WLAN card I'm using only has a 32-bit Windows
driver, and ndiswrapper on 64-bit linux would require a 64-bit driver to
work correctly (which is somewhat stupid IMHO but I'm not going to hack
ndiswrapper).
In the real world, there are tons of silly constraints like this which
still prevent people from fully using 64-bit hardware.

Cheers,
Hans-Martin



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