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Re: RedBoot go command enhancement
On Thu, 2003-01-30 at 09:38, Mark Salter wrote:
> >>>>> Gary D Thomas writes:
>
> > On Thu, 2003-01-30 at 09:12, Mark Salter wrote:
> >>
> >> Here's a patch I've been playing around with. It provides a
> >> mechanism for programs started by the RedBoot go command to
> >> return to the RedBoot prompt and have its exit status displayed.
> >> It also adds a -c flag to the go command which prevents the
> >> caches from being disabled before jumping to the program. I've
> >> only tried it with standalone newlib/libgloss based apps, but
> >> eCos apps should also be able to use the VV mechanism as well.
> >> I thought I'd throw this out and solicit any comments.
> >>
>
> > Nice. My only concern is that "workspace_end" is a scary place
> > to keep the saved context. Maybe this should be in [static] low
> > memory?
>
> Yeah, I have been waffling over that as well. The only problem
> with a static area in RedBoot's area is that there doesn't
> appear to be a good way to figure out the size requirement in
> an architecture neutral way. You need room for HAL_SavedRegisters
> plus some architecturally defined padding. For instance, you
> just need a little padding on ARM for 16byte alignment, but on
> mips there is an extra 56 bytes that is probably an ABI stack
> frame thing.
>
Maybe we should have a HAL_THREAD_CONTEXT_SIZE macro defined
by the architecture? It just seems unsafe that one can't know
how how much of the "stack" is used up for a saved context.
Anyway, now that I look at it closer, I don't think this
really matters because the actual saved return info is
stored on RedBoot's own stack and pointed to by "go_saved_sp".
In other words, ignore my concern. Go ahead with it :-)
--
.--------------------------------------------------------.
| Mind: Embedded Linux and eCos Development |
|--------------------------------------------------------|
| Gary Thomas email: gary.thomas@mind.be |
| Mind ( http://mind.be ) tel: +1 (970) 229-1963 |
| gpg: http://www.chez-thomas.org/gary/gpg_key.asc |
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