PowerPC 405 support

[Michael Eager <eager at eagercon dot com>]

I was looking at adding support to GDB for a variant of
the PPC 405.  This variant has several added instructions
but is otherwise the same, i.e., has the same registers, etc.

I thought I'd add a processor type named Xppc405 or ppc405X
for this variant.  Then I noticed that the 405 is really
not supported as a variant, but the 403 is, and that the 403
has extensions (and at least one hack) for the 405.  There
are opcodes defined for PPC405, but this symbol is aliased
to PPC403.

It looks pretty straight-forward to create a ppc405 variant
and unalias it from the ppc403.  Then create a ppc405X
variant which builds on the ppc405.  Any reason not to do
this?

Alternately I could (a) add the variant's instructions
to the existing PPC405 definition and leave that as an
alias for the PPC403.  That would be quick, but seems dirty.

BTW, does anyone have documentation on the PPC403?  I
can't find any online and if I do unalias PPC405 from PPC403,
I'd like to make sure that the opcodes labeled PPC405 are
really only in the 405, and not also in the 403.


--
Michael Eager	 eager@eagercon.com
1960 Park Blvd., Palo Alto, CA 94306  650-325-8077