GCC for pdp11

[Mattis Lind]

Hello Paul!

When I read this once upon during the summer I saw that the problems I once
had reported was solved and it was great news. Really thankful that you did
so much work with this!

However I know tried to turn on optimizations and then it fails in a
strange way.

If you have some spare time maybe you could check why it fails on when
11/10 but not when set to 11/40. And it only fails for even powers of two
above 16. It is the if that fails so if I remove that one it works.

The bug report is https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88435

/Mattis

Den lör 14 juli 2018 kl 19:51 skrev Paul Koning via cctalk <
cctalk at classiccmp.org>:

>
>
> > On Jul 14, 2018, at 9:46 AM, David Bridgham via cctalk <
> cctalk at classiccmp.org> wrote:
> >
> > Hey, glad to hear of some improvement on GCC for the PDP-11.  Last
> > spring I ended up side-tracked on the QSIC project and working more on
> > FPGA issues than writing PDP-11 code but that's going to change here at
> > some point.  I still want to put a soft PDP-11 into the FPGA as an I/O
> > controller and will need to be writing code for it.
> >
> > For the moment, I'm off at my summer job in Alaska but when I get home
> > this fall, it's back to working away on the QSIC and maybe my PDP-10
> > project where I'm thinking I may also use a soft PDP-11 as an I/O
> > processor.  Anyway, I'll grab up the new GCC and see if my issues with
> > the 'volatile' keyword are still there.
>
> I didn't directly address anything like that, but it may well be that
> things are better.  "Volatile" is a very tricky area.  There is detailed
> discussion in the GCC manual about when volatile objects are accessed.  You
> may want to review that.  Sometimes the rules are not precisely what you
> might expect.
>
>         paul
>
>