Re: RFA: contribute Renesas M32C sim

[DJ Delorie <dj@redhat.com>]

> >> + void
> >> + prefix (src_allowed, dest_allowed, index_bytewidth)
> >> + {
> >> + }
> >
> > And what's that for?
> 
> I don't know.  I thought it was some sort of annotation for opc2c to
> consume, but that doesn't seem to be so.  I'll find out.

I remember talking to Jim about this, but I don't see him answering in
the mail archives, and since I was checking on the m32c/gdb status I
figured I'd at least get this one answered.

In short, that function exists so it can be called, it's the callers
that are important at the moment.

The callers act as documentation for what prefixes and indexes are
permitted for each opcode.  As I was going through the tedious process
of implementing each opcode, I added all the calls to prefix() with
the correct arguments.  The function does nothing yet, but at some
point in the future it may fault if prefixes are used where the real
chip doesn't support them.