Re: Counting bits

Graham Toal says:

Serious optimization isn't a child's game. When we did the 1's-counting code for the Acorn RISC machine, every programmer in the office worked on it for a week. I think the best version in the end was a variation of the trick shown earlier and some sneaky use of ARM conditionals and address-loading instructions that could do arbitrary shifts on the fly while adding.

In my humble opinion, the right way to get code like this written is to let a superoptimizer get a whack at the problem -- superopts produce are guaranteed to produce optimal code, and its better to have fifteen machines grinding for a week than fifteen humans and their machines. Perry