[ODE] Some SSE in Quick step

[GARY VANSICKLE]

> GARY VANSICKLE wrote:
> > AFAIK, nobody's actually ever verified that D3DX's mathematical
> > manipulations are slower than ODE's built-in.  Which is part of why a
> > referred to this as a "non-argument".
> Convenient.
> 

Rather inconvenient actually.

> >>Then there's no need to do some jumptable chachacha à la DirectX when
> >>you're dynamically linking Ode: link against the proper dll (ie
> >>ode-sse2.dll) at run time.
> >
> >
> > As a wise man once sang, "We'd all love to see the plan" ;-).  I'm
> guessing
> > D3DX does at least as well as that.
> Guessing is the key word. Sing with me.
> 

Nah, I'd rather listen to the originals.

> >  It's certainly not doing anything like:
> >
> > If(SSE2)
> > {
> > 	SSE2MatrixMultiply();
> > }
> > Else if(SSE)
> > {
> > 	SSEMatrixMultiply();
> > }
> > Else if...
> >
> > if that's what you're getting at.
> No. Read what i've said again. "jumptable chachacha" has nothing to do
> with the code you've posted.
> 

So you know that D3DX is doing this mysteriously-named "jumptable
chachacha"?

> Picking the proper dll at runtime may be equivalent (more or less) to
> some jumptable adjustment (ie on windows), but it puts some of the
> burden on the toolchain as it relies on compiler/linker mechanisms.
> 

Huh?  No, it relies on the OS's runtime library loading support.

> and
> >>That just require some rather thin per platform gluing.
> 
> > And a huge number of DLL's/.so's,
> You can't have the cake and eat it.
> 

With something like D3DX at least you don't have to bake the cake you can't
eat.

> > which will need to keep growing on an
> > almost monthly basis as new processors come out with new features.
> Yeah sure.
> 

Touche.

> > I say let Bill do it; he already is anyway.
> Again those 2 solutions (linking against different ode libs vs D3D)
> aren't equivalent.

Wait, now you're talking about completely different *ode* libs?!?  When did
we switch from talking about *math* libraries?

> In the former every paths are optmized for one combo (cpu/features).
> 

Again, how many combos do you need to ship?

> And you're still conveniently forgetting that Bill only cares about a
> subset of Ode supported platforms (i know i know, it's one of your
> famous non-argument).

I'm not forgetting that at all.  *You* are forgetting that while you and I
beat the dead "anything but Microsoft" horse, *nobody's* ODE is using any
SSE.

Or do you only care about a subset of ODE's supported platforms?

-- 
Gary R. Van Sickle