[cfarm-users] cfarm26 FP inaccuracies

[Andreas Schwab]

On Aug 30 2026, Martin Guy via cfarm-users wrote:

> On 8/30/26 2:29 AM, Jacob Bachmeyer wrote:
>> Paranoia's page 4 (when run on cfarm26) mentions:
>>
>>     Some subexpressions appear to be calculated extra
>>     precisely with about 11 extra B-digits, i.e.
>>     roughly 3.31133 extra significant decimals.
>>     That feature is not tested further by this program.
>>
>>
>> about 11 extra bits would be consistent with the x87 80-bit format
>> vs. standard 64-bit double...
> Well spotted! I bet that's it as the differences were microscopic.
> So it's calculating intermediate results with too much precision for the
> IEEE. I'm not sure that's a defect!

-mfpmath=387 vs -mfpmath=sse