Re: sh64 simulator register numbers

[Andrew Cagney <ac131313@ges.redhat.com>]

> Andrew Cagney wrote:
> 
>> See the directory gdb/regformats/ and (more importantly) the mail
>> archives for information on the changes that are being made to GDB so
>> that it will eventually be able to handle remote register numbers.
> 
> 
> Hmm. Interesting.  But the documentation seems to be mostly in the 
> 'looking for volunteers' stage.
> 
> Can you give some salient time frames and/or keywords to narrow down the
> search space a bit?

Some words would include regcache remote.c (especially all recent patches).

>> > !   /* SHmedia */
>> > !   SIM_SH64_R0_REGNUM = 128,
> 
> 
> So you want this assignment to 128 be dropped, so that SIM_SH64_R0_REGNUM
> just gets the next free number?

Yes, a pure enum.  As mentioned before, the d10v et.al. all do this.

> The rest is all relative to SIM_SH64_R0_REGNUM.
> There are 64 general purpose registers, starting with R0.  The stack
> pointer is R15. 
> 
>> > !   SIM_SH64_SP_REGNUM   = SIM_SH64_R0_REGNUM+15,

If a register has an alternative name, define that in a separate enum vis:

	enum {
	SIM_SH64_SP_REGNUM = SIM_SH64_R15_REGNUM
	};

> After the general purpose registers, we want the program counter.
> Is this assignment OK with you?
> 
>> > !   SIM_SH64_PC_REGNUM   = SIM_SH64_R0_REGNUM+64,

No.  See above.

> Or do you want r63 to be assigned a number relative to r0, and then
> get automatically the next number for pc?
> 
> Or should we enumerate all 64 of the general purpose registers?

Yes.

> Similar considerations apply to the 64 control registers,
> 8 target registers, how to assign a number to fpscr, and
> the 64 floating point registers.

Andrew