[Ffmpeg-devel] [PATH] test if cpu supports CMOV

Guillaume POIRIER gpoirier
Mon Oct 16 22:54:31 CEST 2006


Michael Niedermayer a ?crit :

> this will break runtime cpudetect (yeah i know my crap code already
> broke it but thats not supposed to stay that way in svn)
> solution:
> 1. clean configure so that
> --cpu  selects the minimum cpu required (-mcpu/-march)
> --tune selects the target cpu for which to tune but doent cause possibly
>        unsupported instructions to be generated (-mtune)

Ok, I had a look at current configure, and I'm quite surprised.
 From what I can see, currently, --cpu (which already exists) allows to 
select an Architecture, _not_ a CPU.
This means that the first step IMHO is to rename this missleading option 
to --arch (as in attached patch).
Then add --cpu option to allow to set -march (which implies -mtune so no 
need to always set --cpu and --tune) (this is mostly what current --tune 
does, so that would pretty much mean to rename $tune to $cpu).
Then add --tune so it ONLY sets -mtune. (without code duplication 
between --tune and --cpu)

As you can see, if we want to do this (which is certainly desirable), 
what kinda mean we do perfect_shuffle(configure_option).
I don't mind, but users may hate this.

BTW, do we agree that we aren't looking for automatic CPU detection as 
things are done in MPlayer's configure?


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