On Tue, Jul 30, 2013 at 4:47 PM, Kristoff Bonne <krist...@skypro.be> wrote: > Marcus, > > (repost due to technical problems. My appolologies for a possible double > post). > > > > On 30-07-13 21:41, Marcus D. Leech wrote: >> >> On 07/30/2013 03:35 PM, Kristoff Bonne wrote: >>> >>> Tom, >>> >>> >>> (inline comments) >>> >>> >> My understanding was that all IEEE floating-point implementations followed >> the same rounding rules, etc? Is that not the case? >> >> Are the SIMD subsystems not IEEE compliant, for performance reasons?
Yeah, actually, not all SIMD subsytems are IEEE compliant, though off the top of my head, I can't tell you any more than that. So it is possible that precision issues can come into play here. There are a number of Issues on our project page that I believe are related to this exact problem (basically on different ARM processors with and without NEON). > As said, I'm not an expert in code-optimisation. > > I did look up the discussions. It was more then "a few weeks ago", they date > back to January this year. :-) > > There are two discussions that might be interesting: > http://sourceforge.net/mailarchive/forum.php?forum_name=freetel-codec2&viewmonth=201301 > > "c2dec produces different wav-files on i386 and on ARM" and "adding compiler > flags" So codec2 shouldn't be using Volk, but if it's using some other SIMD code itself, that could be a problem. The problem with just turning off a QA test because it fails is that we're now just hiding a potential problem. I'd rather understand the problem and try and patch it as opposed to shutting our eyes and pretending everything's ok :) -- Tom Visit us at GRCon13 Oct. 1 - 4 http://www.trondeau.com/grcon13 _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
