[OE-core] [PATCH][RFC] cortexa8: use hard floating point

Phil Blundell philb at gnu.org
Thu Aug 18 08:57:45 UTC 2011


On Wed, 2011-08-17 at 23:16 -0700, Darren Hart wrote:
> From what I could gather, it makes sense to address using mfloat-abi=hard
> for the beagleboard in the cortexa8 tune file. Before I submit this as a pull
> request, I'd appreciate a sanity check from the Beagleboard experts.
> 
>[...]
>
> mfloat-abi is currently set to soft for beagleboard (cortexa8) and needs to be
> set to hard to take advantage of the floating point hardware.

Have you benchmarked this change?  It isn't really true to say that hf
needs to be set to "take advantage" of the FP hardware; you will still
get most of the benefit of the VFP without it.  I would be surprised if
this made much of a difference on any real-world workload.

Changing -mfloat-abi is (obviously) an ABI change and is definitely not
the sort of thing to do capriciously.  If you apply the patch in its
current form then it will make cortexa8 binaries incompatible with
everything else by default, which is probably not going to be a good
thing.  I think this ought to be a DISTRO choice not a machine one.

p.






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