Hi, Scott wrote: >It's probably clear from the comments how it works. :) as crystal :) pretty clever if i might say so, index parity in the top bit :) had some ideas but no so sofisticated, I'll see what the weekend gives but doubt I'll improve anything. You managed to do calculations for both bytes in parallel and that is hard to improve unpon.=20 We'll see, /Tony -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body