Multiple ISAs for opcodes

[Doug Evans]

Ben Elliston writes:
 > I'm trying to generate the opcodes files for a port which has two
 > ISAs.  The ISA shares some instruction names and this leads to
 > collisions in the cgen_insn_type enum (in the <arch>-opc.h file).

For the sake of discussion, is this something akin to arm vs thumb?

 > Before I work towards a solution to this, I'm trying to understand the
 > workings of the cgen-generated opcodes files.  Was it the intention
 > that a single set of files should be able to handle the entire
 > architecture?  If so, would the right fix be to include the ISA name
 > in the generated symbols to prevent these name collisions?