On Wed, 14 Jul 1999, Bruce Momjian wrote:
> > 3) -mieee informs the egcs compiler fot the alpha to inject 'trapb'
> > instructions at various places in a floating point computation. The trapb is a
> > pipeline stall forcing the processor to stop issueing instructions until all
> > current instructions in the pipeline have executed. This is done to capture a
> > possible 'fault' at a resomable time so you can backtrack to the instruction
> > that faulted and take some corrective measure. There are also rules for
> > backtracing, and repairing. The usage of -mieee inserted these trapb's all over
> > the place. The current egcs compiler appears to do a better job at it For
> > purely int operations, then a module need not be enhanced by the -mieee switch.
>
> I am stumped on why we even need -mieee, but someone supplied a patch to
> add it.
That someone would be me. :) I supplied a patch to add about a
year ago as that was the only way I could get some of the date/time code
work correctly. If it is needed anywhere anymore, then it is down in
src/backend/util/adt, as that is where the datetime code is/was that were
causing FPEs to occur on regression testing. Without that flag, the
datetime code used to blow up all over the place. Might be worthwhile to
try removing it, recompiling, and running regression tests to see if it
needed anymore. That, and fixing the datetime code so it is not needed in
the first place (if it is still needed).
The biggest problem area for pgsql on Linux/Alpha at the moment is
in the datetime code, including what reltime and abstime regression tests
exercise.
If anyone wants me to test pgsql patches on Alpha, feel free to
send them my way, and I will give them a test on my XL366 Alpha running
Debian 2.1.
TTYL.
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| Ryan Kirkpatrick | Boulder, Colorado | rkirkpat@nag.cs.colorado.edu |
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