RFA: V850 sim: various fixes.

[nick clifton]

Hi Mike,

>>    It also adds a snippet of code to catch attempts to
>>    execute code via a NULL pointer.
>
> usually the simulator represents the hardware.  so if the hardware has
> memory at address 0 and someone were to load up an image with code
> there, there's nothing invalid when it comes to jumping there.

Personally I see the simulator as more of a testing and debugging tool. 
  It does not try to be hardware accurate - it does not model the cache 
for example - so adding a feature that helps catch program errors, even 
if it not strictly modelling the hardware, seems OK to me.

> what i do on the Blackfin side when it comes to testing is to have the
> ELF manually pad the start with insns that'll trigger an exception
> (just like it would on the hw).  then i set the entry point beyond
> that.

Another fine approach.  I'll see what DJ thinks, but I will be happy
to remove the NULL trapping part of the patch if he does not like it.

Cheers
   Nick