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Re: gdb/remote - I/O
On Wed, Mar 28, 2001 at 11:54:15AM -0500, Frank Ch. Eigler wrote:
> : Most targets, even the cheap eval boards available for low end
> : microcontrollers have more than one I/O channel, so I use one for
> : GDB and another for system I/O.
> From the point of view of test suites and similar automated control,
> the fewer physical connections, the better. Several remote debugging
> protocols include console I/O already; we would like to finally bring
> "remote" closer.
> : But if I needed to route I/O through GDB, I think I'd want some-
> : thing richer than a single serial i/o stream. Perhaps some sort of
> : lightweight filesystem layer with open/read/write/close primitives.
> : [...] If we're going to change the protocol, why not make it something
> : richer than a single stream? [...]
> Yes, this would be a worthwhile exercise, but is way outside
> the realm of reasonably small extensions of the remote
FWIW, RDI defines several independent comm channels between
host and target that are multiplexed into one data stream. The
RDI target code supports open/read/write/close semantics for
using the "semi-hosting" channel (or whatever it's called) to
open/read/write file descriptors. I'm not recommending RDI as
a good model -- RDI is an overly complicated protocol even
considering the features that are supported (like
I don't know how well the semi-hosting stuff works, but it's
there as an example of how ARM Ltd. addressed the problem.