[Squeak-VMdev] Fw: Q: Lowest level VM changes

[Andreas R. <and...@gm...>]

I'm forwarding David's reply here - I don't know if there are any
implications for the stuff we're talking about wrt. V4 but if anyone has an
insight into these areas it might be worthwhile to keep some of this in
mind.

Cheers,
  - Andreas

----- Original Message ----- 
From: "David P. Reed" <dp...@re...>
To: "Andreas Raab" <and...@gm...>; <dav...@be...>;
<al...@sq...>
Sent: Wednesday, April 07, 2004 4:37 PM
Subject: Re: Q: Lowest level VM changes


> I don't think we know what is best at this time.  It's clear that the
> inter-teaparty message send has a common-case fast-path.   But it's too
> early to guess what the change should be.
>
> Prbably the biggest other win would be around making it much more
efficient
> to use floating point (which we do in tea-times as well as in the 3D
> stuff).   Since floats are put on the heap, it might be worth looking at
> the techniques we used in MACLISP interpretation to put intermediate
floats
> in a "number stack" that was much more efficiently allocated and freed
> (allocate = push onto the temporary number stack).   Coupled with
compiling
> sequences of math operations and tests into a "math mode" byte code stream
> that checks types on the inputs and then just runs a different byte code
> interpreter without any further type checking, this could speed up math a
> lot.   It's a kind of  optimistic or speculative execution concept.   This
> coupled with the matrix stuff would make Croquet a kick-ass math
interpreter.
>
> At 05:26 PM 4/6/2004, Andreas Raab wrote:
> >Hi,
> >
> >I am just in an extremely low-level discussion with some people about the
> >benefits of various kinds of lowest-level VM changes and I was wondering
if
> >there is anything in Croquet where certain modifications of the VM could
> >make huge differences. If you have anything where you say "oh, it would
be a
> >*huge* improvement to have support X, Y, or Z" this would be a very good
> >time to voice it. Note that I am not making any promises here - just that
I
> >might be able to throw something in that helps us support what you think
is
> >needed.
> >
> >   - Andreas
>