Old O'Reilly X books
Aaron Plattner
aplattner at nvidia.com
Thu Aug 26 08:11:33 PDT 2010
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
More information about the xorg-devel
mailing list