Old O'Reilly X books

[Aaron Plattner]

On Thu, Aug 26, 2010 at 05:43:53AM -0700, Pat Kane wrote:
> BTW, while trying to grep my dead trees I noticed that the current X server
> contains some HAKMEM code, in ./mi/micmap.c I see this hack:
>     ...
>     count = (visuals >> 1) & 033333333333;
>     count = visuals - count - ((count >> 1) & 033333333333);
>     count = (((count + (count >> 3)) & 030707070707) % 077);	/* HAKMEM 169 */
>     ...

Hah, awesome.

Apparently that code sucked in 1995 and still sucks today:
http://compilers.iecc.com/comparch/article/95-07-080

I increased the loop count by two orders of magnitude:

NAIVE:    5.616 sec
HAKMEM:   7.541 sec
HAKMEM_P: 8.381 sec