Image format proposals... Re: [SqF]Report of VI4 Project for
Feb '02
Hannes Hirzel
hirzel at spw.unizh.ch
Sun Feb 3 11:09:19 UTC 2002
Just curious: Could somebody give me a pointer to the object header format
actually currently?
Hannes Hirzel
On Sun, 3 Feb 2002, Scott A Crosby wrote:
> On Sun, 3 Feb 2002, Scott A Crosby wrote:
>
> > On Sun, 3 Feb 2002, Hans-Martin Mosner wrote:
> >
> > --
> > Switch to 128/64-bit headers?
> >
> > -- 64 bits
> > 18 length (all zero's indicate long header)
> > 2 object type
> > 00 - Object contains no references
> > 01 - Object is a forwarding pointer.
> > 10 - (long header) 4th word in header is an oop to be checked in GC
> > 11 - Object weakly references other objects.
> > 4 for reserved for GC.
> > 8 unused. (for immutible, special behavior, etc) [*]
> >
> > 16 hashbits
> > 16 class# (looked up on a seperate table)
> > --
>
> Rereading, its wrong, but you get the idea of the brainstorm.
>
> There needs to be a combination in the object type that signifies that its
> a normal object.
>
> Scott
>
>
>
>
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