Re: ser-ocd.c gone! What now?

[Steven Johnson <sjohnson@neurizon.net>]

DJ Delorie wrote:
> 
> I answer this only in the context of the GNU GPL...
> 
> > About DLLs: when you write a OCD/BDM/JTAG back-end for a debugger you
> > need to have internal knowledge of how the processor works. Often you
> > can only get this information by signing a NDA.
> 
> The mere fact of the NDA may disqualify that code from any GPL'd
> program.  Being in a separate file (the dll) may not exempt it and
> gdb from being one "work" by legal definitions.
> 

Regarding XFree86, The XFree86 Team do not link to proprietary DLL's.  
They have a driver model, and certain vendors ship non open source 
drivers (like Nvidia).  The other distinction is XFree86 is not 
licenced under the GPL. Further vendors that do protect these debug
interfaces with NDA's are destroying the benefit of implementing them
in the first place (cheap and easy and readily available )

> 
> > With ser-ocd.c gone (and it probably won't be back in, will it?) I have
> > to find a new method to communicate with the processor. As far as I can
> > see there is no way to talk to locally attached hardware (cable at
> > parallel port). I could use the remote protocol and write a dedicated
> > server. This has two disadvantages. First, it is a lot of work. Second,
> > it is not really efficient if GDB and the server are on the same host.
> >
> > Perhaps I'm missing a simple method. If anybody knows of a different
> > solution please let me know.
> 
> The GPL allows this solution - distribute your changes as a patch, in
> source form, without the DLL or base GDB sources.  The GPL only comes
> into affect when you create a binary (either gdb or the dll) *and*
> distribute it, and only applies to GPL'd sources.  If the patch is
> entirely written by you, you can distribute just the patch under other
> terms, as long as it includes *no* original gdb sources or binaries
> built from them.

I have created just such a server for the MPC860 (not to dissimalr to
the
ibm chip you mention, both being powerPC.) To explode some of your 
misconceptions about just such a server. 1. It was less work than
hacking 
GDB because the interface is well defined (less than 1 week of labor for
me)
2. It is no slower than ser-ocd, in fact I believe it is a tad faster.

It also has the advantage that the debugger does not have to be on the
same
computer as the one attached to the device being debugged (as long as
you
use TCPIP).

Steven.