[Vm-dev] Compiling squeak.cog.spur on Pi

[Phil (list)]

On Fri, 2016-06-24 at 11:35 -0700, tim Rowledge wrote:
>  
> 
> > On 24-06-2016, at 11:09 AM, Eliot Miranda <eliot.miranda at gmail.com>
> > wrote:
> > 
> > 
> > Here are useful extracts of messages from Ryan Macnak on the
> > topic.  They imply to me the need for separate v6/Pi and v7/Android
> > builds.
> > 
> > On Feb 11, 2016, at 7:43 PM, Ryan Macnak <rmacnak at gmail.com> wrote:
> > 
> 
> > 
> > ARM doesn't have great backwards compatibility either. I've tried
> > running an ARMv6 compiled Cog on an ARMv8 board, and it crashes
> > because the VM includes a memory fence instruction that is
> > deprecated and has a replacement in ARMv7 and optionally (and in
> > practice) disabled in ARMv8. So it doesn't look like one can
> > provide a single binary that supports ARMv6-8. Again the embedded
> > systems mentality that one builds for a specific device.
> > 
> 
> And yet the cog vms for Raspbian work on Pi3 (ARMv8) Pi2 ARMv7 and Pi
> B (ARMv6)
> 

Yes, because the Pi Foundation is going to great pains (to the
detriment of features and performance on newer Pi boards) to retain
backward compatibility.  The rest of the ARM world is the wild, wild
west.  Different strokes and all that...

> tim
> --
> tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
> Bayard(n): a person armed with the self-confidence of ignorance
>