[ECOS] Re: CPU Ports for eCos

[Bart Veer <bartv@cygnus.co.uk>]

>>>>> "Fernando" == Fernando D Mato Mira <matomira@iname.com> writes:

    Fernando> At 03:09 PM 4/28/99 +0100, you wrote:
    >> Probably true, if there are no problems with copyright
    >> assignments etc. For example the gcc port to the MC68HC11 could
    >> not be merged because of assignment problems. Anybody
    >> interested in doing this should contact the egcs maintainers,
    >> http://egcs.cygnus.com, to find out what would be involved. A
    >> Cygnus port of eCos to this architecture is not currently under
    >> consideration, so it is unlikely that we will do this work any
    >> time soon.

    Fernando> I don't know about that port, but in this case they were
    Fernando> distributing a derivative of GCC. Whatever their backend
    Fernando> was, it was then infected by the GPL (I guess that's the
    Fernando> only reason why you could order the source code for $200
    Fernando> or something like that).

Copyright assignments and the GPL license are actually separate issues
in this context. The GPL license means (amongst other things) that if
some company or individual X modifies the compiler and makes the
result available to Y then X also has to make the sources available to
Y. Neither X nor Y are obliged to contribute the changes back to the
central maintainers. In practice changes are usually contributed back
because the alternative is merging problems whenever there is a new
release of the main sources (or you get stuck with an old version of
the main sources and you miss out on new optimizations etc.)

For those changes to get accepted into the main sources, a copyright
assignment is needed. The author of any non-trivial changes has to
assign all rights to those changes to the FSF, thus avoiding any
confusion about who owns which bits of the compiler. The GPL does not
impose any obligations in this area, it is a voluntary step, but in
most cases it is worth doing to avoid the merging problems.

As I understand it, in the case of the 68HC11 there were numerous
contributions by different people with no tracking of who contributed
what, and when they wanted to merge the changes into the main sources
there was no way of getting all the people involved to sign the FSF
assignment forms. Hence the maintainers could not accept the code. The
situation for the Analog Devices port may be very different.

More details on the procedures can be found on
http://egcs.cygnus.com/contribute.html 

Bart Veer // eCos net maintainer