[ECOS] MORE question about "VIRTUAL_VECTOR_SUPPORT"

[Tony Ko]

Tony Ko wrote:
>> 
>> hi.
>> look at the satement below,
>> "Enable use of virtual vector calling interface. Virtual vector
support
>> allows
>> the HAL to let the ROM monitor handle certain operations."
>> 
>> does this satement mean " when exception occurs  while ecos running,
>> the exception can be processed by REDBOOT" ?
>> I think ROM monitor is same with REDBOOT in this case.
>> If so, some exception can be processed by REDBOOT exception handler
even
>> while eCos running, right?

>I'm not quite clear on what you are asking here. But yes the
application
>will hand over certain operations to RedBoot using virtual vectors. 

==> Does this mean that " a RAM-loaded eCos app can hand over exception
processing to 
       ROM-loaded REDBOOT using virtual vectors ? " 
       Then why does app do that?

>But in most cases when it comes to processor exceptions, a RAM-loaded
eCos
>app will not take over the processor exception vectors in the first
place -
>but that's not related to *virtual* vectors.

==> I don't understand this statement clearly. Could you explain in
more detail?
       And what does VIRTUAL really mean in this case?

thanks, Tony.