[AD] Re: CPU detection for Macintosh

[Peter Hull <peter.hull90@xxxxxxxxxx>]

On Wednesday, February 2, 2005, at 12:23  am, 
alleg-developers-request@xxxxxxxxxx wrote:

> I must have missed it, but I think think it's a nice feature to have.
> Afterall, we're supporting it for Intel machines, might as well support
> some other common ones too ;)
> Then again, Allegro doesn't use hand-made assembler code under OS X, 
> does
> it? The main usefulness of CPU detection is in the use of hand 
> optimized
> machine code...
> (yes, that's saying I'd like there to be more hand optimized assembler 
> code
> for other platforms ;))

It is better than the current which just reports "non-Intel CPU, cool 
;)" or something similar. At the moment, it just detects a PowerPC and 
its variant. Since the PPC market is more 'uniform' than x86 it should 
be possible to determine the presence of Altivec or 64-bit extensions 
just by looking at the variant number. I didn't do this because, as you 
say, Allegro doesn't make any use of it.
Maybe some decent use could be made of VecLib or the Accelerate 
framework 
(http://developer.apple.com/hardware/ve/vector_libraries.html), I'm not 
sure.
IMO, more assembly code is not the right way to go because it increases 
the load necessary to port Allegro, and the benefit of asm are 
decreasing as compiler optimisation gets better.

Pete