On Wed, 23 Oct 2002, Anthony Hannan wrote:

> "Andrew C. Greenberg" <werdna at mucow.com> wrote:
> > Can anyone account for this remarkable increase in speed?  I would
> > think that the incorporation of block closures would tend to slow,
> > rather than increase the speed of the interpreter.  Is something
> > missing or counted differently, or should we immediately dump the
> > present VM for a way more efficient machine?
>
> The increase in speed is due to getting rid of context objects in favor
> of a stack, and getting rid of the frame pointer and having all stack
> accesses be referenced from the stack pointer which is in a register.
> See the aboutVI4 method comment or the description at
> http://minnow.cc.gatech.edu/squeak/VI4 for more details.

Anthony,

I've been puzzling over how to adapt #callCC to this change.  What I need,
more or less, is some way to capture and copy the current stack, IP,
etc, and then restore these at a later point - even once the original
stack has been unwound.

The naive approach (copying FiniteStack objects and messing with the
'stack' ivar of Process2) tends to segfault the VM.  Suggestions?

Avi