Re: [f-cpu] Supported Instructions

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

On Sun, Apr 07, 2002 at 05:05:23PM -0600, Ben Franchuk wrote:
> Michael Riepe wrote:
> 
> > Personally, I think that performing a task switch *every time* the CPU
> > enters or leaves an interrupt/trap handler is inefficient. But I already
> > stated that a while ago.
> 
> I say don't use IRQ lines as HIGH SPEED DMA! instead.

Fine, Ben... here is your cookie... now go back to sleep.

No wait... please explain to me how to use DMA for an `invalid opcode'
trap, will you?

Besides that, a DMA engine will have to tell the CPU that it has finished
its job - via an interrupt, unless you're willing to waste CPU time with
polling status bits (in that case, you could also do the data transfer
in software and use that precious silicon for something more useful).

-- 
 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/