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Re: Double word ints on PPC 604e
- To: "Bryan D. Lee" <bryan dot d dot lee at lmco dot com>
- Subject: Re: Double word ints on PPC 604e
- From: Geoff Keating <geoffk at cygnus dot com>
- Date: 15 Aug 2000 20:40:59 -0700
- CC: gcc-bugs at gcc dot gnu dot org
- References: <200008151513.LAA21648@mal-ach.watson.ibm.com> <3999619D.4DF84F5A@lmco.com>
"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>