[Haskell-cafe] Re: fast integer base-2 log function?

[Chad Scherrer]

Jens Blanck <jens.blanck <at> gmail.com> writes:

>  {-# LANGUAGE MagicHash #-} import GHC.Exts import Data.Bits -- experiment
with using a LUT here (hint: FFI + static arrays in C)
> ...

Sorry I don't have an answer, only more questions.

Is {-# LANGUAGE MagicHash #-} documented somewhere? I've seen it referenced a
few times now, but I can't find any details about it.

Chad