Joern,

This is an advance hint that I am working on the next generation LSI
from Renesas.  Apparently at this stage I am allowed to mention its
name (sh2a), but nothing more.  ;-/

The first thing I need to do is free up some room for new insns.
The jump table is just about full (it can only hold 255 entries).
This patch splits the dsp instructions (the contents of movsxy_tab)
into their own jump table.  As a side benefit, it's no longer
necessary to swap them in and out of the main jump table at
runtime.  This gives us room to add lots of new instructions.
It passes all my regression tests (and I have some that I haven't
submitted yet).

Earlier today, you mentioned your concern about runtime efficiency.
I haven't done any performance testing, but since this makes the
main switch statement smaller, I imagine it might have some benefit
(similar to ifdeffing out the contents of movsxy_tab).

Michael