Re: Cycle stepping

[Andrew Cagney <ac131313 at cygnus dot com>]

Michael Hayes wrote:
> 
> I'm in the process of revitalising the tic4x target for submission.
> One big change that I've noticed is that a simulator can no longer use
> any of gdb's routines.
> 
> Now one useful feature we had with the c4x simulator was to provide
> single cycle stepping to observe the operation of the pipeline.  This
> was achieved by adding a couple of new commands to gdb's interpreter
> (stepc and nextc) whenever the c4x simulator was fired up.  Now in the
> process of making the c4x simulator stand-alone, does anyone know of a
> simple way that this functionality can be added to gdb?
> 
> Presently, stepc is similar to stepi but we use a flag to tell the
> simulator to stop after a cycle.  Is there a mechanism for
> communicating parameters like this to the simulator to avoid having to
> add another argument to target_resume?

You could table a proposal that ``step'' become an enum - run=0,
stepc=1, stepi=2.  Which would accomodate backward compatibility.

	Andrew

(Disclaimer - I've not thought this through and from memory you also
need a bit of serious WaitForInferior hacking).