Hmmm... delicious bitmasking. That's when you know the author is serious about squeezing performance out of a JS VM: forcing 32 bit integer optimizations.

Note that the hilbert function wasn't written by me, just merely ported from C++ — here's a post about it by the original author: http://threadlocalmutex.com/?p=126

> here's a post about it by the original author: http://threadlocalmutex.com/?p=126

Nice!

But still: you did port it from C++, and consciously or not, that optimization still applies.