[RFI]Mac performance gap between OS-9 and OSX

Tim Rowledge tim at sumeru.stanford.edu
Tue Aug 5 23:08:51 UTC 2003


"Andreas Raab" <andreas.raab at gmx.de> wrote:

> Every now and then you should try a different machine ;-)
Blasphemy! Off with his head! Red hot pokers up the fundament! Comfy
chair!

> However, due to not changing the byte ordering of all of the *internal*
> forms of Squeak this has precious little effect because byte-endian-swapping
> blits are naturally more expensive and the VMs byte-reversal stuff has been
> optimized for years (up to the point that the assmbly code is proven
> optimal) so unless you change all of the internal forms too, there is no
> clear speed advantage going little endian here.
Exactly the point I intended to make. The ancient little-endian blit I
did involved having _all_ bitmaps changed to suit. Unhibernating did the
work, mostly. There's lots of places where one needs to take care though
I strongly suspect it could be cut down dramatically with a good think.
It all got to be too much effort to keep tracking every little bitmap
related update and make a patch. Especially as absolutely nobody but me
cared.

> 
> If you are interested in this you should just give it a try - merely have
> your VM answer true if queried for a negative display depth in
> primitiveTestDisplayDepth and you'll be able to go forth and back between
> little and big endian pixels.
Well, not quite that simple since something -ve got fed to a place where
it shouldn't go. I'll see what needs changing.


tim
--
Tim Rowledge, tim at sumeru.stanford.edu, http://sumeru.stanford.edu/tim
Useful random insult:- Has his brain on cruise control again.



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