class formats

Andreas Raab andreas.raab at gmx.de
Tue May 16 17:01:10 UTC 2006


 > Can anyone confirm this? Or am I wrong?

That is exactly correct. It's a little implementation trick so that the 
format doesn't have to be "normalized" for allocation. It originates 
from the days when even a shift was too slow in allocation; personally I 
find it a little awkward.

Cheers,
   - Andreas

Michael Haupt wrote:
> Hi,
> 
> apologies for the cross-post to two lists, but I wasn't too sure where
> to ask this.
> 
> I've just been browsing the VM sources for details on the encoding of
> class formats used in object instantiation.
> 
> Apparently, it seems as if the class format word that can be retrieved
> by sending #format to a class has the same layout as the standard
> header word of all objects. The only difference seems to be that the
> format word is shifted left by 1.
> 
> Can anyone confirm this? Or am I wrong?
> 
> Thanks,
> 
> Michael
> 
> 




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