Re: Ada and Automotive Industry

[otto@olcs.com (Otto Lind)]

In article <5743un$muj@news.nyu.edu>,
	kenner@lab.ultra.nyu.edu (Richard Kenner) writes:

> There is no GCC port to the 68HC11 and none has ever been submitted
> for consideration in the years I've been in charge of GCC maintenance.
[munch]
> What you must be talking about is somebody's preliminary attempt to
> port GCC to that processor.  Clearly they didn't even think enough of
> it to submit it for consideration in the GCC release.

Well, I did and try to submit it; both to you, and an assignment of
copyright to the FSF.

The problem was that Richard Stallman found some problems with the
copyright assignment that I sent back in December of 1994, but never
bothered to let me know about it.  I resubmitted the assignment in April
of this year, after bugging the FSF folks again, and finalized the
paperwork for the assignment.  Therefore, the copyrights for the gcc
specific code located at:

ftp.skypoint.com:/pub/members/o/ottol/gcc-6811-fsf.tar.gz 

has legally been assigned to the FSF.  I did not bother trying to
resubmit the port to you, since others were working on improving it, and
indicated that they would pick up maintenance (this was why I went
through the re-assignment process).  It looks like this never happened.

> GCC makes no such assumption.  It knows precisely how many registers are
> available and what each can do.  It does tend to do better on machines
> that have a lot of registers, but that's true for most compilers.
[munch]
> The code quality is poor most likely because the person who did the
> port did it badly.  It is somewhat tricky to do a port to a machine
> with a small number of registers because some of the config file macros
> that select which hueristics to use are relatively unimportant on
> machines with lots of registers, but are much more important on
> machines with only a few.

"somewhat tricky"?  I challenge you or anyone else to do a port of gcc to
a processor with an extremely small register set without having to
substantially modify the generic code in the reload modules.  If you know
of any gcc port which supports a processor which has one accumulator and
two (or one) index registers, I would be interested in seeing it.

I will freely admit, this is a sub-optimal port.  The one thing that
could done to greatly improve it would be to redo the machine description
file to support the native 6811 registers and clobber them appropriately. 
However, I don't believe it is possible to get rid of the "virtual"
registers scheme I used without rewriting generic gcc code.  Please prove
me wrong on this point.

Otto

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