[yocto] [meta-raspberrypi] Why not enable hard floating point?

[Andrei Gherzan]

Hello,

On Fri, Jan 16, 2015 at 3:05 AM, J. Tang <tang at jtang.org> wrote:

>
> On 2015-01-15, at 04:06, Mike Looijmans <mike.looijmans at topic.nl> wrote:
>
> > -2- The CPU doesn't actually have floating point support and the kernel
> is emulating it for you. This allows the platform to run "hf" binaries, at
> a minor performance cost compared to completely doing the emulation in user
> space (libc).
>
> From my understanding, the Raspberry Pi (at least the model B, which is
> what I have) has an FPU.
>
> Would it hurt to at least mention in the top-level README of the
> meta-raspberrypi layer that a user could enable hard FP by setting the
> DEFAULTTUNE?
>
>
Definitely it wouldn't. But right now we have two options:
We can just throw a README line and that's it.
Or we can  investigate a little to see if in our current setup we actually
use FPU instructions or not. Following Mike's answer I would definitely
think that we are in case 1 where the compile based on the CPU
configuration figures out that we can use FPU instruction on this CPU
architecture. Right now, as being on vacation, I can really test on
binaries by dissembling code and check it by hand. Anybody who can do it
and provide some feedback? As well, some bench-marking would really make
sense here.

Thanks guys.

-- 
*Andrei Gherzan*
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.yoctoproject.org/pipermail/yocto/attachments/20150118/96da73c7/attachment.html>