[Ffmpeg-devel] [PATCH] SSE counterpart of ff_imdct_calc_3dn2

Dave Dodge dododge
Thu Aug 24 22:54:42 CEST 2006

On Thu, Aug 24, 2006 at 08:15:05PM +0200, Reimar D?ffinger wrote:
> On Thu, Aug 24, 2006 at 01:10:18PM -0400, Dave Dodge wrote:
> > IA64 compilation is an ongoing research project.
> Which is what leaves me always wondering where on earth (or actually far
> away from earth) Intel engineers left their brains when designing
> IA64...

I can sort of see the logic in moving the scheduling and pipelining
work to the compiler.  The compiler can take its time working out the
best paths, and the chip can be simpler.  But then assembly code ends
up being a scrambled mess in order to avoid stalls, so it's hard to
read, hard to write, and hard to deal with in a debugger.  I recall
SPARC had the same things going on back in the early 90's

IA64 takes it to a whole new level, and the instruction bundling and
grouping stuff you have to deal with is just too much.  Lots of
interesting tools and libraries never get ported to IA64 because they
need some machine-specific assembly and nobody wants to deal with
writing it.

> Technology for the next century. As in we will get it to work properly
> somewhen in the next century...

By that point AMD64 may have caught up in terms of memory and core
count scalability, eliminating the main reason to use IA64 at all.

                                                  -Dave Dodge

More information about the ffmpeg-devel mailing list