Anthony,

> The methodCache entry size need to be a power of 2 and is currently 8,
> but only uses 5 slots.  What if we take primitiveIndex out so
> our entry size can be 4 with all slots used.  It will be almost as
> quick to fetch the primitiveIndex from the method once the
> primitive bits are put together in the header.

Whoa! Slowly here. Don't claim anything that you can't prove (e.g.,
measure). Many of the primitives are quick (such as return instVar x) and
taking them out of the cache can slow down your system much more than you'd
think.

Cheers,
  - Andreas