Re: [Qemu-devel] I want to add the ARMv6 instructions, who can give some advices?

[Jamie Lokier <jamie@shareable.org>]

Paul Brook wrote:
> > Qemu is already compatible "in part" with the the instructions and
> > models described in the manual, isn't it?
> >
> > So by the language of clause 2(i), aren't you _already_ prohibited from
> > working on Qemu's ARM code?
> 
> All the information used to implement the current qemu Arm support is 
> available from other sources not covered by this licence. I'm confident I 
> could prove this if necessary.

Of course, I'm sure you're right.

In the thread you cited earlier, Wolfgang Schildbach refers to "ARM
System Developer's Guide", by Sloss, Symes, and Wright, Elsevier 2004
as documentation that may be sufficient for Qemu ARMv6 support, and
which is not covered by the license.

If ARMv6 support were developed by someone else, using only that book,
and maybe looking at other code (GCC, Linux etc.), that would prove
that all the information used is from other sources not covered by the
license, wouldn't it?

The support might be missing a few features, if the other information
sources are incomplete, but even incomplete support that can be
deduced from those sources would be good enough for most purposes.

If that were done, you could prove that the resulting feature in Qemu
was written using sources not covered by the license.

So would you have any problem contributing to Qemu after ARMv6 support
was integrated, if the person who contributes ARMv6 support states
that they have never seen the ARM document and refers to the sources
they have used instead?

-- Jamie