[Vm-dev] VM Maker: VMMaker-dtl.350.mcz

[David T. Lewis]

On Mon, Sep 08, 2014 at 03:11:31PM -0700, Eliot Miranda wrote:
>  
> On Mon, Sep 8, 2014 at 2:43 PM, Tobias Pape <Das.Linux at gmx.de> wrote:
> 
> >
> > Hi,
> >
> > On 08.09.2014, at 23:23, David T. Lewis <lewis at mail.msen.com> wrote:
> >
> > >
> > > Hi Eliot,
> > >
> > > Agreed, the primitive will need to be rewritten to work with a 64-bit
> > > SmallInteger. There may be other integer primitives that will need
> > > attention too, although I have not looked.
> > >
> >
> > Having tried implementing other SqueakVMs, my impression is, that the
> > SmallInt-is-31-bit assumption is like everywhere. Starting with some
> > int-primitives and not ending with bitBlt. We really have to be careful
> > here.
> >
> 
> That's what tests and sheer bloody-mindedness are for ;-)
> 

A full frontal assault is one possible approach, but it may be worth
considering the strategy that Dan used for the image format 68002 64-bit
image. In this object memory, the object format allows for very large
SmallInteger values, but does not require them. The minVal and maxVal
for SmallInteger can remain unchanged in the image, and everything just
works.

With that strategy, the task of converting the image to take advantage of
the new SmallInteger object format can be separated from the task of getting
the Spur 64-bit object memory and VM up and running.

Dave