Re: [Squeak-VMdev] Versiojn 4 changes

[Tim R. <ti...@su...>]

In message <011401c41c2b$d09ba810$b2d0fea9@R22>
          "Andreas Raab" <and...@gm...> wrote:

> > Just another data point: some Smalltalk implementations put the
> > SmallInteger tag in the topmost bit.
[snip]
BrouHaHa being one example.
> 
> Hm... if we'd accept cutting the address range in half (which isn't that big
> of a deal) that is actually a pretty interesting idea. It would allow us to
> use low bits as "other tags" similar to immediate, say 00->oop, 01->GC flag,
> 10->Character, 11->Undefined, without too much of a bother.
> 
> The only objection I'd have is whether this would have any effects on
> machines that "like to give you the upper half of the address space" (e.g.,
> all addresses must have that "tag bit" set).
I'd say this was a bit of a problem. BHH didn't have an issue since
OOPs were indices into an OT and thus never had much chance of
exceeding a few million. Especially on a machine with 1Mb ram total...

tim
--
Tim Rowledge, ti...@su..., http://sumeru.stanford.edu/tim
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