The following overview SIMD Within A Register (SWAR).
One of the first talks on the concepts of SWAR... originally presented in February 1997 at Purdue University. The HTML is a little ugly, but this is the original HTML, and the server it was on supported different server-side processing....
One of the best generic descriptions of the concepts of SWAR. The above link is direct from Springer-Verlag.
@inproceedings{663771, author = {Randall J. Fisher and Henry G. Dietz}, title = {Compiling for SIMD Within a Register}, booktitle = {LCPC '98: Proceedings of the 11th International Workshop on Languages and Compilers for Parallel Computing}, year = {1999}, isbn = {3-540-66426-2}, pages = {290--304}, publisher = {Springer-Verlag}, address = {London, UK}, }