Liboil is a library of simple functions that are optimized for various CPUs.
These functions are generally loops implementing simple algorithms, such as
converting an array of N integers to floating-point numbers or multiplying
and summing an array of N numbers. Clearly such functions are candidates for
significant optimization using various techniques, especially by using
extended instructions provided by modern CPUs (Altivec, MMX, SSE, etc.).

Many multimedia applications and libraries already do similar things
internally. The goal of this project is to consolidate some of the code used
by various multimedia projects, and also make optimizations easier to use by
a broad range of applications.

WWW: http://www.schleef.org/liboil/