[Coco] xroar host debugger project?

[Joel Rees]

Ciaran,

Letting you know I got it to build and have been able to use it.

Posted some notes on building here:

https://joels-programming-fun.blogspot.com/2022/10/notes-on-building-m6809-gdb-for-use.html

Thanks.

2022年9月19日(月) 2:34 Ciaran Anscomb via Coco <coco at maltedmedia.com>:

> Joel Rees via Coco wrote:
> > [...]
> > >
> > > Can I just be sure you're not talking about attaching GDB to an XRoar
> > > process here?  I'm talking about the port XRoar can listen on (with the
> > > -gdb option) that GDB can connect to.
> >
> > Without the patches, I don't think I have anything to attach to but
> > the SRoar process.
>
> So with the "-gdb" option, XRoar listens on a TCP port for GDB to
> connect to.  That's just built in.  At the time, any GDB could connect,
> it's just way more helpful if GDB knows about 6809 - which is what my
> patched branch of ye olde GDB does.
>
> > > (And if you yourself want to attempt similar, GDB supports custom
> > > protocol additions - the 'q' commands - so we should be able to allow
> > > inspecting/changing other bits of hardware than the RAM, too).
> >
> > I've been thinking that direction, as well.
>
> If you start to look into it, the general GDB remote protocol descriptions
> are useful:
>
> https://sourceware.org/gdb/onlinedocs/gdb/Remote-Protocol.html
>
> And there are some comments at the top of "gdb.c" in the XRoar source
> suggesting some of the current extensions...  well, actually it's just
> inspecting the SAM register so far.  If you get to the point where you
> want more information out of the emulated machine through more protocol
> extensions, I'm quite happy to discuss.  Clearly adding GIME state to
> that would be required too...
>
> (Oh and another caveat: the GDB support in XRoar only covers the
> 6809-based machines so far).
>
> > > > Building the patched version of gdb -- will that require messing
> > > > around in /dev or such? Or can the patched debugger run in userland?
> > >
> > > No, userland: http://www.6809.org.uk/dragon/m6809-gdb.shtml
> >
> > That page shows the command
> >
> >    git clone -b m6809-7.6 https://www.6809.org.uk/git/binutils-gdb.git
> >
> > So I tried the clone, exactly as written, and the clone just never
> > starts. I have to ctl-C to get my terminal back after waiting two or
> > three minutes, and there's nothing in the directory I'm cloning to.
>
> Hm I tried it and it does complete, just takes a long time.  It's quite
> a big repo...
>
> If you periodically "du" inside the "binutils-gdb" it creates for the
> checkout you should see it growing.  It gets there eventually - 372M
> and 9716 files ;)
>
> > You have this note:
> >
> >     2016-05-30: This repository has changed because the source
> > repository for GDB changed. It is now based on
> > git://sourceware.org/git/binutils-gdb.git ,
> >
> > But I nosed around in there and didn't see patches for the 6809, and
> > trying to clone that, the branch m6809-7.6 is not found.
>
> No indeed, that's the upstream repo, my branch is just based on that.
>
> > > I did write a quick & dirty getting started note here:
> > >
> > > http://www.6809.org.uk/tmp/xroar/m6809-gdb.txt
> >
> > That does look good, if I can get the repository.
> >
> > Thanks for walking me through this.
>
> No worries - hope you get it built.  It's an old version of GDB now, so
> it's going to get more and more difficult I suspect.  I had to rebuild my
> local copy today to test all this due to some python libraries changing
> underneath it...
>
> ..ciaran
>
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