1. A computer implemented method of performing a SIMD operation on a data set, said method comprising: selecting a stored bit mask for reorganizing said data set to facilitate performance of said SIMD operation on said data set; reorganizing, after said selecting step, at least a first portion of said data set as said data set is loaded into a SIMD processing unit, wherein said reorganizing is performed according to an application specific register; performing said SIMD operation on said data set after said reorganizing step; and writing a result of said SIMD operation to a destination register after said performing step.