Re^3: Efficient bit-twiddling in Perl.

[Tux]

I think you can shave off a lot in XS (or Inline::C) when you switch to prebound variables, ala bind_columns () in DBI or Text::CSV_XS, as much of the XS overhead is stack-work. That said, it then is still is function calls, so the stack will be involved. If you pre-bind both in- AND out- parameters, you don't need to push variables on the stack and pop return values of the stack. That should speed up quite a bit.

The next step could be looking in to op-hooks, so there are no real perl-level function calls anymore, but looking at what you already have, I'm wondering if it would be worth the effort (other than to learn from it),

The lookup solutions have array-index ops in the back. I am stunned by the 20% gain you get, and wonder if that would differ per perl version and/or architecture.

Anyway, the solution that is fastest on the machine the problem is solved on is most important, even if another method would be four times faster on z/OS with perl4 :)