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

[Michael Riepe <michael@stud.uni-hannover.de>]

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)?

-- 
 Michael "Tired" Riepe <Michael.Riepe@stud.uni-hannover.de>
 "All I wanna do is have a little fun before I die"
*************************************************************
To unsubscribe, send an e-mail to majordomo@seul.org with
unsubscribe f-cpu       in the body. http://f-cpu.seul.org/