[Vm-dev] Re: [Pharo-project] Latest image from jenkins does not open with interpreter vm

David T. Lewis lewis at mail.msen.com
Thu Mar 15 20:15:47 UTC 2012

On Thu, Mar 15, 2012 at 08:11:02PM +0100, Igor Stasenko wrote:
> On 15 March 2012 20:05, Guillermo Polito <guillermopolito at gmail.com> wrote:
> > Ok, so I have no chose.?? I have to move SystemTracer to cog, or do it :D
> >
> Yes. We need to make it working with Cog.
> Hope, Eliot remembers what is essential changes between 6502 and 6505
> formats, which needs to be fixed in system tracer.

Eliot described the details in a recent posting, but I don't think
you actually need to do anything for system tracer. It can already
trace to a 6504 format, which can be loaded by Cog. IIRC you may
need to save the traced image one time from an interpreter VM before
loading it in Cog, but otherwise I think it's working. It would be
nice to get it to trace all the Cog details as well, but it's a
lot easier to just keep an interpreter VM around to save the image
one time before you switch to Cog.

Also, any recent interpreter VM can load a 6505 format saved from
Cog, so the only practical problem is that we still have outdated
interpreter VMs in circulation.

I should think that it would be possible to add a "post processing"
step at the end of a Jenkins image build in which the newly built
image could be resaved with an interpreter VM. That would allow you
to build the image with Cog, and save the result in a format that
can be loaded with practically any VM that the user might happen
to have installed.

I have tried to document the various image formats, including unit
tests, in order to capture the information that Eliot provided
as well as the variations related to 64-bit object memory images.
Please load package ImageFormat from the VMMaker repository, it's
convenient to keep it at hand for reference and it does not conflict
with anything else in Squeak/Pharo/Cog/Interpreter VM.


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