Re: Add support for RedBoot SWIs to ARM Simulator

[Richard Earnshaw <rearnsha at arm dot com>]

> Hi Richard,
> 
> > This may trample on the toes of somebody using that SWI as a real
> > trap into an OS.
> 
> Well it would if they were then trying to run code compiled for that
> OS on the simulator.
> 
> > We probably should have a way of configuring the simulator at 
> > run-time to allow emulation of a set of SWI values.  Either from a  
> > command-line switch (for the arm-...-run command) or a gdb hook (for use 
> > within gdb).
> 
> > Something like:
> > 
> > 	arm-elf-run -emul-swi={redboot|angel|demon|none}
> 
> Hmm, well that could be done.  Personally I would hold off doing it
> until there is actually a situation where it is needed.  At the moment
> support all three SWI interfaces simultaneously is not a problem.  So
> unless someone comes up with a real situation where it causes problems
> I would leave things as they are.  (Just my 2 cents worth).
> 
> Cheers
>         Nick
> 


Actually, we already have.   Look at the mess that is involved with 
testing for XScale -- saying that XScale doesn't support Demon swi's is 
nonsence -- especially when we default to enabling XScale extensions for 
some simulations.  I ran into something like this only the other day -- 
the simulator was turning on XScale (despite the fact that I wasn't using 
any of those extensions), and thus disabling the SWIs I wanted.

Note the comment at the top of ARMul_OSHandleSWI which really gives the 
game away:

  /* Intel do not want DEMON SWI support.  */
  if (state->is_XScale)
	...

R.