[Zlib-devel] Google's version of zlib code

[Jan Seiffert]

Arjan van de Ven schrieb:
> interesting; did you only play with the alder32 code, or did you do
> other parts as well?
> 

I started with adler32.
After optimizing it for IA64 i felt dizy...
So i watched for other oportunities for vectorisation.

The sliding hash calculation (when the deflate window is "updated")
is a classic subtract with saturation, so i also did that.
It's in the slhash branch.
https://github.com/kaffeemonster/zlib/commit/b42095f4f19fba56e8dc22bfc95b3a73eb7988a8

> (my tweak to adler32 was very simple,
> http://git.fenrus.org/git/?p=packages/zlib.git;a=blob;f=adler-speed.patch;h=62bf22ba456fb95e3dabb616edcc2705d3720c7b;hb=HEAD

Wow, ok, that is simple. The classic problem of exploding the register
file.

> ... but as someone who works for Intel, I can appreciate someone
> writing it in ssse3 ;-)
> 

SSE, pfff

https://github.com/kaffeemonster/zlib/commit/10b2cd8dd6bc204b2fa19c1f4e3e75a95e71b454

Greetings
	Jan

[snip]