Re: d3dx9: Avoid expensive computations

[Nozomi Kodama]

Rico,

can you give a try to this patch?
If it is slightly slower than native, we could at first merge it.

Anyway, if the application is well coded, this function should not be called often. Usually an application uses transformations matrices that are a lot easier to inverse

Nozomi

________________________________
 De : Henri Verbeet 
À : Rico Schüller  
Cc : [e-mail]; Nozomi Kodama  
Envoyé le : Lundi 25 février 2013 0h08
Objet : Re: d3dx9: Avoid expensive computations

On 25 February 2013 10:24, Rico Schüller  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.