Στις Tuesday 09 September 2008 01:00:42 ο/η Rogério Brito έγραψε: > This might explain my impression in a private mail to Charles Plessy > that my iBook G3 was quite faster under Linux than under MacOS X. > Apparently, MacOS X is *made* *for* altivec machines.
True, Altivec is quite extensively used in MacOS X, which is not sth I can say for any core component of Linux, sadly. This was exactly the reason I started libfreevec in the first place. > This would be very welcome addition to glibc. Especially for the > "weaker" chips that don't have any vectorial part. These won't be accelerated though, only in the case that the original algorithm was optimised as well, > This part about not using altivec is interesting, since I would like to, > say, be able to watch DVDs with my iBook and not have them drop so many > frames. Decoding theora videos is also quite CPU intensive... :-( Well, I can't really say how much faster decoding will be with faster libm functions, but 3D definitely will be faster. > > > just by choosing a different approximation method (Taylor > > > approximation is pretty dumb if you ask me anyway). > > What are you using, BTW? CORDIC? No, Pade approximations. CORDIC iirc, is also not that much faster than Taylor. I have some relevant paper around but I can't seem to find it right now, but I could look it up if you really like. Anyway, the libm rewrites will be accompanied by a math paper full with proof and benchmarks, so I guess you will see the method used :) Regards Konstantinos Margaritis Codex http://www.codex.gr -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
