[Vm-dev] Accelerating LargeIntegersPlugin phase 2

Frank Shearar frank.shearar at gmail.com
Sun Jan 20 17:53:25 UTC 2013

On 20 January 2013 17:39, David T. Lewis <lewis at mail.msen.com> wrote:
> On Sun, Jan 20, 2013 at 04:52:42PM +0000, Frank Shearar wrote:
>> On 20 January 2013 15:37, David T. Lewis <lewis at mail.msen.com> wrote:
>> >
>> > I'll mention also that, although much work remains to be done in merging
>> > oscog and trunk VM code bases, I think that overall we are doing very
>> > well with the primitives.  The VM primitives are now almost all in class
>> > InterpreterPrimitives, and changes can easily by adopted in both branches.
>> > Likewise, the plugins such as LargeIntegersPlugin can easily be kept in
>> > sync in the two branches.
>> >
>> > That means that changes like these can be tested and adopted in either
>> > branch at the convenience of the person doing the work. I'm doing my
>> > best to pick up changes as they are added to Cog, and Eliot is doing
>> > likewise with changes that show up first in the interpreter VM.
>> >
>> > I don't happen to have a big endian machine, but hopefully someone else
>> > has one and can help out with the testing, using either an interpreter
>> > VM or Cog VM.
>> At the risk of sounding rather ignorant, what kind of machine would
>> that be? IIRC the 68k machines were big endian but they've been wiped
>> out now haven't they?
> Most certainly not, Edgar still has one.

OK, that's pretty much what I meant :)

> Wikipedia gives a good summary: http://en.wikipedia.org/wiki/Endianness
> Older Macs are big endian, and the Squeak VM was originally written on
> big endian machines. ARM processors can run in either mode. Most likely
> they run as little endian for Linux, and I'm not sure which mode is used
> for RISC OS.

Sadly my old macs went to the knacker's yard.

> In any case, keeping the VM healthy for big and little endian machines is
> important to ensure portability of the VM. You never know when somebody
> is going to want to do a VM for System 360 ;-)

Oh, I agree entirely! It keeps folks honest.


> Dave

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