Generating CPU family headers for multiple isas

[Ben Elliston]

   : I think it makes sense to do so, yes.
   : [...] It makes just as much sense for the ARM isa to
   : have a h-gr element as it does for Thumb.

   But is this isa-specific *hardware*, or an isa-specific *operand*? The
   thumb & arm modes of the chip share physical registers, n'est ce pas?

To simply matters, much of the "baby" hardware is virtual -- it just hooks
registers into the superset.  How could this be done without isa-specific
hardware?

Ben