Re: RFA: PowerPC sim & GDB: use fixed register numbering

[Andrew Cagney <cagney@gnu.org>]

> Andrew Cagney <cagney@gnu.org> writes:
> 
>>>> > Andrew Cagney <cagney@gnu.org> writes:
>>>> >
>>>
>>>>>> >>> Have a look at the other sim-*.h files, you'll notice that most define
>>>>>> >>> an enum namespace and not a series of magic constants.   Can we expand
>>>>>> >>> the table so that the constants aren't needed?
>>>
>>>> > Is this going in the right direction?
>>
>>> 
>>> Yes, that should go in.
> 
> 
> Okay, committed.  Thanks to you and Kevin for the review.

Ok,

> The old code, which did an under-the-covers call into gdb to map number -> name, was bad and definitly needed to be replaced.  The above though could still do with some work - too much on the magic of those numbers in gdb/sim-ppc.h :-(
> 
> Anyway, lets first get the enum in place. 

Since we've nailed the enum, what should we do about the sim/ppc?

>>> What's your plan with SPRs?
> 
> 
> I think it's best to use the SPR numbers assigned by the ISA to
> identify them.  Trying to keep tables based on automatically assigned
> enum values in sync would take a lot of work, for little gain, since
> ISA SPR numbers are (obviously) unambiguous within any particular PPC
> variant.

Which is a change from the status quo.  That was doing things based on 
the ISA's register name.  Which ever.

> At the moment, the sim doesn't support any SPRs from different PPC
> variants whose numbers clash.  There'll be work needed there to handle
> that; I don't have any particular insights there.

Andrew