[theora-dev] Issues with Win32 MMX code

Nils Pipenbrinck n.pipenbrinck at cubic.org
Wed Feb 4 04:07:34 PST 2009

Ralph Giles wrote:
> On Mon, Feb 2, 2009 at 9:38 PM, Nils Pipenbrinck
> <n.pipenbrinck at cubic.org> wrote:
>> After thinking about the problem I've suggested to remove all optimized
>> frag_recon assembler functions and replace them with MMX intrinsic based
>> versions. My hope is that the problem will dissapear that way because
>> the new functions will be no special cases for the compiler anymore.
> Hard to say. In theory the intrinsics might compile on gcc too
> someday, which would be great. But you say in the bugzilla thread that
> you expect the intrinsics version to be slower. Benchmarks are in
> order, I think.
I'll do some benchmarks. I have a preliminary port of the frag_recon 
things using intrinsics, and to my big surprise they compiled without 
any problems using GCC under cygwin.

I'll give it a try under linux as well, but I see no reason why it 
shouldn't work.

I'll also do some further investigation for the mozilla-guys. Imho it 
should be possible to just link the mmx functions from a pre compiled 
object file without whole program optimization data.

That effectively disables WPO for the file. VC can't mess up the the 
code that way. We wouldn't even have to write a single line of code...  
I'll check how good that works in practice.


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