[Vm-dev] Re: [Pharo-project] Integrating Changes in 1.4 that require a new VM

[David T. Lewis]

On Thu, Sep 22, 2011 at 11:37:46AM -0700, Eliot Miranda wrote:
>  
> On Thu, Sep 22, 2011 at 11:28 AM, Igor Stasenko <siguctua at gmail.com> wrote:
> >
> > Do you think this will require boosting an image format version number?
> 
> That would make sense.  Boosting it so that the new VMs can run older images
> and newer, ephemeron images, but that ephemeron images won't open on older
> VMs.  Yes, this makes perfect sense.

Please use image format number 6521, allocating bit 5 as the "ephemeron support bit".

Details:
  6505 printStringBase: 2 ==>  '1100101101001'
  ImageFormat bitsInUse printStringBase: 2 ==> '10001100111101111'

"Next available bit is bit 5"
  2r1100101101001 ==> 6505
  2r1100101111001 ==> 6521

"A 64 bit image with cog support plus ephemeron support would be 68019"
  (ImageFormat wordSize: 4 cog: true) asInteger ==> 6505
  (ImageFormat wordSize: 4 cog: true) asInteger bitOr: 2r10000 ==> 6521
  (ImageFormat wordSize: 8 cog: true) asInteger ==> 68003
  (ImageFormat wordSize: 8 cog: true) asInteger bitOr: 2r10000 ==> 68019

  6505 printStringBase: 2 ==> '1100101101001'
  6521 printStringBase: 2 ==> '1100101111001'
  68003 printStringBase: 2 ==> '10000100110100011'
  68019 printStringBase: 2 ==> '10000100110110011'

If you agree, I'll update ImageFormat and ImageFormatTest to document
the new format number assignments.

Dave