3D Math Data structures/SIMD

[Sascha Katzner]

Lukas Pinkowski wrote:
> SIMD instructions are pretty 'old' now, but the compilers support them only
> through non-portable extensions, or handwritten assembly.

One reason could be that, it is a performance penalty for the OS to save 
the SIMD registers (XMM1, XMM2...etc.). You can verify that with the 
test programm attached to this posting. If you uncomment lines 27-30 the 
programm is ~50% slower (9.8s vs 6.7s on a Core 2 Duo E6750 on Vista).

SSE is great if you do a lot of heavy computations in your program, but 
if you only do a dot product here and a cross product there you better 
not use SSE, because your whole program runs a lot slower if you use SSE 
instructions.

LLAP,
Sascha Katzner
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