Thread: [brlcad-devel] BRL-CAD Configure Message: IEEE Floating Point Handling Incorrect
Open Source Solid Modeling CAD
Brought to you by:
brlcad
From: Tom B. <tom...@gm...> - 2009-01-09 17:58:18
|
Sean, I get the following message (and I guess I always have with gcc) with gcc 4.3.2: configure: }}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}} configure: WARNING: The floating point implementation does not seem to be IEEE 754 configure: WARNING: compliant. The behavior of htond and htonf may be incorrect. configure: {{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{ Is that a gcc bug? BTW, I don't see 7.14.0 in the News on the web site. Happy New Year to all. -Tom |
From: Christopher S. M. <br...@ma...> - 2009-01-10 13:04:21
|
Tom, No, it's not a bug but it is an an (completely unverified) potential issue inside our serialization code. The test was added to see how prevalent non-IEEE floating point types are (which is actually exceptionally prevalent). Whether and implementation is complaint is dependent on compilation options and your hardware type. If it's always done it for you, it's undoubtedly just a nature of your hardware type that GCC is taking advantage of. You can sometimes force IEEE floating point with a gcc option (like - mieee), but those are similarly dependent on your hardware type. The impact of the bug is that we have one place in the code that assumes an IEEE floating point encoding when writing single-precision floating point values out to .g files. Fortunately, we rarely ever use single-precision floating point (not a single location comes to mind actually, but probably somewhere) but the potential issue would be a floating point value that was stored/serialized on one (non-IEEE compliant) platform into a .g file would appear as a different value when that .g were read/deserialized on a different (IEEE-compliant) platform. Basically it's a warning/TODO item to verify the serialization behavior at some point. Cheers! Sean On Jan 9, 2009, at 12:56 PM, Tom Browder wrote: > Sean, I get the following message (and I guess I always have with gcc) > with gcc 4.3.2: > > configure: }}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}} > configure: WARNING: The floating point implementation does not seem to > be IEEE 754 > configure: WARNING: compliant. The behavior of htond and htonf may be > incorrect. > configure: {{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{ > > Is that a gcc bug? > > BTW, I don't see 7.14.0 in the News on the web site. > > Happy New Year to all. > > -Tom > > ---------------------------------------------------------------------- > -------- > Check out the new SourceForge.net Marketplace. > It is the best place to buy or sell services for > just about anything Open Source. > http://p.sf.net/sfu/Xq1LFB > _______________________________________________ > BRL-CAD Developer mailing list > brl...@li... > https://lists.sourceforge.net/lists/listinfo/brlcad-devel |