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Re: MORE question about "VIRTUAL_VECTOR_SUPPORT"
- To: Tony Ko <nhko at gctsemi dot com>
- Subject: Re: [ECOS] MORE question about "VIRTUAL_VECTOR_SUPPORT"
- From: Jonathan Larmour <jlarmour at redhat dot com>
- Date: Tue, 18 Sep 2001 21:12:13 +0100
- Cc: ecos-discuss at sources dot redhat dot com
- Organization: Red Hat UK Ltd.
- References: <0F61D7853F0B434A90567901F0D604EF08041C@gctsemi.gctsemi.com>
Tony Ko wrote:
>
> 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?
Define "exception" and I might have a clue what you're asking.
> >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?
Not real vectors - they are vectors (in the computer science sense) but
they are not *hardware* vectors, so we named them "virtual".
Jifl
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