[coyotos-dev] Status and roadmap

[Jonathan S. Shapiro]

On Fri, 2007-01-19 at 10:29 -0500, Jonathan Adams wrote:
> On Fri, 2007-01-19 at 14:28 +0000, Sam Mason wrote:
> > On Thu, Jan 18, 2007 at 04:57:41AM -0500, Jonathan S. Shapiro wrote:
> > > The kernel specification has been public for quite some time, and the
> > > implementation is already underway.
> > 
> > The work is showing, section 3.3.2 (or was it 3.3.3) only documented
> > what happened when the Activated field was in one state---I see this has
> > been filled out to both now.
> > 
> > One thing that worries me now is where the kernel gets the memory to
> > "synthesize a message to be delivered" when the userland scheduler is
> > activated.  In fact where does this memory come from in the general
> > case?
> 
> The message is a "short" message, which any non-blocked FCRB can receive
> without needing additional storage.

Oh. Perhaps I misunderstood Sam's question.

Sam: can you say which place in the manual that came from? It sounds
like I need to clarify that text.

There are two cases: message delivery and execution exception delivery.
In the message delivery case you have a payload that is in an FCRB that
is delivered to receiver registers. In the exception delivery case, you
have fields in the process state that are being delivered to receiver
registers.

run-in with no exception (i.e. after preemption, but with no pending
message) is a special case of exception delivery (an exception message
is delivered with a cause field of "noException").
-- 
Jonathan S. Shapiro, Ph.D.
Managing Director
The EROS Group, LLC
+1 443 927 1719 x5100