Double word ints on PPC 604e

[Geoff Keating]

"Bryan D. Lee" <bryan.d.lee@lmco.com> writes:

> Dave,
> 
> I've got little/no choice in the matter, it's the version of gcc that
> our version of vxWorks uses.  But I'm thinking that the situation I'm
> describing is a problem even in the latest release.

Could you try to make a proper bug report?

It's quite unlikely that any problem with 2.7 is still present in the
current release.  There have been thousands of changes.

> > Bryan> I'm trying to use "long long" integer type on a PPC 604e with gcc
> > Bryan> 2.7.  I keep getting exceptions when trying to run the compiled code.
> > Bryan> I don't see a compiler flag for running on a 604e vs. a 604 (the 604e
> > Bryan> has no built-in 64-bit integer type).  I would have thought that gcc
> > Bryan> would translate the long long type data manipulations into 32-bit
> > Bryan> operations, but now I'm not so sure.

The 604e and 604 are essentially the same processor.  Current gcc does
anyway have an option for chosing the 604e, -mcpu=604e, but all it
really changes is the scheduler (I think the 604e had an extra
function unit or something).

Yes, GCC performs 64-bit arithmetic by using the add-with-carry instructions.

-- 
- Geoffrey Keating <geoffk@cygnus.com>