On Fri, 14 Sep 2012, Vincent Lefevre wrote: > round-to-odd would be a good solution if it were provided directly > in hardware. Otherwise a "direct" implementation would probably be > more efficient (in particular when the implementation of the usual > operation is done in software, like for decimal arithmetic).
It's the case for a lot of libm operations that the best implementation for software floating point is not the same as for hardware floating point (anything implemented using Dekker's algorithms or similar precision extension techniques would probably better use higher precision more directly on integers, for example). It's also the case that there hasn't been any actual interest in optimal software implementations for these cases in glibc (I guess people concerned about floating-point performance are generally using hardware floating point). -- Joseph S. Myers jos...@codesourcery.com
