On Thu, 9 Feb 2012, Geert Bosch wrote: > While I think it would be great if there were a suitable > GNU libm project that we could directly use, this seems to only > make sense if this could be based on the current glibc math > library. As far as I understand, it is unlikely that we
No, that's not the case. Rather, the point would be that both GCC's library and glibc's end up being based on the new GNU project (which might take some code from glibc and some from elsewhere - and quite possibly write some from scratch, taking care to ensure new code is properly commented and all constants are properly explained with free software code available to calculate all the precomputed tables). (Is sysdeps/ieee754/dbl-64/uatan.tbl in glibc - a half-megabyte file of precomputed numbers - *really* free software? No doubt it wouldn't be hard to work out what the numbers are from the comment "x0,cij for (1/16,1)" and write a program using MPFR to compute them - but you shouldn't need such an exercise to figure it out, such generated tables should come with free software to generate them since the table itself certainly isn't the preferred form for modification.) There are permissively licensed GNU projects, such as ncurses. You just need to make the case properly for the choice of project structure and licensing being the right thing for the GNU project (in this case, it makes sense to have one master place maintaining libm code for use in all projects needing it). And, where existing LGPL code in glibc is not assigned to the FSF or is assigned with assignment terms preventing permissive licensing, indeed it won't be possible to use that code in a permissively licensed project. But there's probably plenty that can be reused and cleaned up from various places, taking e.g. all the various bugfixes and enhancements in different forks of Sun fdlibm. -- Joseph S. Myers jos...@codesourcery.com
