On Tue, Feb 28, 2012 at 4:32 AM, Christophe Gisquet <[email protected]> wrote: > Hi, > > in my profiling, ff_sbr_apply accounts for ~12% of the decoding time, > but it has a lot of inlining. The divisions I modify seem to account > for ~5% of that, so precomputing them is interesting. Disassembly > shows a gcc 4.6.2 on x86 64 with -funsafe-math-optimizations does not > do this, while the attached patch does remove 2 such divisions. Not > sure what part of these explanations is interesting to put in the log > message.
A possible improvement to this on x86 would be to use rcpps (fast reciprocal); if extra precision is needed, an added iteration of Newton's method will achieve ~22 bits out of 24 bits of expected precision. Jason _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
