On Thu, 2012-03-29 at 12:11 -0700, Per Bothner wrote: > I would expect the opposite: On modern systems arithmetic (including > bitwise operations) is effectively free, but cache misses are > expensive, > so compact data structures are what counts. > > You wouldn't use a read-modify-write instruction except for "volatile" > accesses. I can report at least one system (not Scheme) that I know promotes bitvectors to bytevectors for speed purposes precisely because masking out the bits is too expensive. In my own tests this has been born out as well. -- Aaron W. Hsu | arcfide@x | http://www.sacrideo.us Programming is just another word for the lost art of thinking.
Description: This is a digitally signed message part
_______________________________________________ Scheme-reports mailing list Scheme-reports@x http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports