On Tue, 7 Jan 2014, Florian Weimer wrote: > On 01/04/2014 07:21 PM, Joseph S. Myers wrote: > > > FYI: a draft set of C bindings for additional floating-point functions > > from IEEE 754-2008 are now available (draft TS 18661-4): > > Is there an accurate summary of IEEE 754-2008 available online?
No. It's available for purchase from IEEE, or through IEEE Xplore if you have a site subscription to that. (ISO/IEC/IEEE 60559:2011 is just IEEE 754-2008 with different cover pages / front matter.) > I'm asking because IEEE 754 is widely quoted, but nobody really seems to know > what's in it. (It seems that some operations are allowed to be off by an ulp > or more, for instance, which I find rather surprising.) The IEEE 754 operations are corrected rounded. However, the C bindings choose to provide most of the recommended operations from IEEE 754-2008 subclause 9.2 only in versions with unspecified accuracy, and not in correctly rounded versions, with names being reserved for the correctly rounded versions but no requirement that those functions be provided. (As far as I know, the state of the art on exhaustive searches for worst cases for correct rounding - as needed to implement correctly rounded transcendental functions with bounded resource use - does not make such searches feasible for IEEE binary128, which is a clear reason not to require such functions to be provided.) -- Joseph S. Myers jos...@codesourcery.com