Re: [f-cpu] More Dark and Dusty Corners

[nicO <nicolas.boulay@ifrance.com>]

Michael Riepe a écrit :
> 
> Quick reply...
> 
> On Tue, Sep 04, 2001 at 11:08:28PM +0200, whygee@club-internet.fr wrote:
> [...]
> > >> > According to the manual, the running SRB must finish before a new one
> > >> > can be started, but that's not appropriate -- why finish something you
> > >> > have to undo anyway?
> >
> > it is because when it returns, it would be very complicated
> > to know if the register was saved or something like that.
> >
> > In fact i think that i remember : If you interrupt one SRB
> > by another, we can't know which register belongs to what.
> [...]
> 
> Hmm... gotta think that over.
> 
> But there still are open questions.  Is a context switch *one* SRB, or
> two (save/reload) in sequence?  Do the "events"
> 
>         - syscall instruction
>         - trap instruction
>         - rfe instruction
>         - external interrupt
>         - exception/fault
> 
> cause a context switch, or do they only save (or restore, in case of
> rfe) the registers?  And where does the *new* CMB pointer come from
> if a second event occurs while the SRB from the first is still active
> (which probably triggers a second SRB)?
> 

And what about a "context switch" instruction (SRB ?)? Something that
launch the SRB as previously design (asynchronous but in order) but
explicitly so we cover different cases.

nicO

> --
>  Michael "Tired" Riepe <Michael.Riepe@stud.uni-hannover.de>
>  "All I wanna do is have a little fun before I die"
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