d3dx9: Avoid expensive computations

[Henri Verbeet]

On 25 February 2013 10:24, Rico Schüller <kgbricola at web.de> wrote:
> I did some small tests for speed with the following results. You may also
> avoid such a lot of variable assignments like *pout = out and you may use 4
> vecs instead. This should save ~48 assignments and it should also improve
> the speed a bit more (~10%). Though, native is still 40% faster than that.
>
I'd somewhat expect native to use SSE versions of this kind of thing
when the CPU supports those instructions. You also generally want to
pay attention to the order in which you access memory, although
perhaps it doesn't matter so much here because an entire matrix should
be able to fit in a single cacheline, provided it's properly aligned.