PATCH: add pa2.0 system instructions

[Jerry Quinn]

>> "jeff" == Jeffrey A Law <law@cygnus.com> writes:

 jeff>   In message < 14209.5087.709459.591226@gargle.gargle.HOWL >you write:
 >> I mostly started playing to get in the extra opcodes for long displacement
 >> float load/store but started to look at completing the pa2.0 support.  So
 >> I added the easy (!) stuff first.
 jeff> Certainly the way to go.  I started with the easy stuff too ;-) The
 jeff> load/store support is some of the ugliest stuff in the new PA2.0
 jeff> support.  I'm hoping you did a cleaner job than I so that I can toss my
 jeff> code in favor of yours instead of trying to rewrite mine.

For what it's worth, if we can free up a bunch of codes I can get ldw
relatively clean (no extra state vars) using about 5 or 6 new codes.  How does 
yours work?

Jerry