Re: [PATCH] MIPS: Handle the DSP registers for bare metal

[Pedro Alves <palves at redhat dot com>]

On 12/19/2014 01:22 PM, Yao Qi wrote:
> Pedro Alves <palves@redhat.com> writes:
> 
>> The proper solution for this issue is to decouple GDB's internal
>> register numbers from the target's g/G packet layout, which is exactly
>> what happens when you have a description -- GDB uses the offsets found
>> in the target description.  And you're touching code that is parsing a
>> description, so the real issue should be in the target description.
> 
> So, these dsp registers on bare metal target have different layout from
> them on linux target, the stub should send the org.gnu.gdb.mips.dsp
> feature with some different "regnum", is that correct?  On linux target,
> gdbserver sends
> 
> <feature name="org.gnu.gdb.mips.dsp">
>   <reg name="hi1" bitsize="32" regnum="72"/>
>   ...
> </feature>
> 
> on bare metal target, the stub should send
> 
> <feature name="org.gnu.gdb.mips.dsp">
>   <reg name="hi1" bitsize="32" regnum="73"/>
>   ...
> </feature>
> 
> is it right?
> 

That should work.  "regnum=" is really only needed to force gaps.  If
you include extra registers in the description, GDB will display them.
So you could also do:

<feature name="org.gnu.gdb.mips.dsp">
  <reg name="acx" bitsize="32"/>
  <reg name="hi1" bitsize="32"/>
  <reg name="lo1" bitsize="32"/>
  <reg name="acx1" bitsize="32"/>
  <reg name="hi2" bitsize="32"/>
  <reg name="lo2" bitsize="32"/>
  <reg name="acx2" bitsize="32"/>
  <reg name="hi3" bitsize="32"/>
  <reg name="lo3" bitsize="32"/>
  <reg name="acx2" bitsize="32"/>
  <reg name="dspctl" bitsize="32"/>
</feature>

Thanks,
Pedro Alves