Re: Does ARMEL toolchain include NEON support?
On Thu, Feb 28, 2019 at 06:47:30PM +0200, Adrian Bunk wrote:
>On Thu, Feb 28, 2019 at 09:05:04AM +0000, Ian Campbell wrote:
>>
>> To spell it out: the gist of this is that it isn't possible to provide
>> a single arm binary which works well for both armel and armhf (which I
>> think is what Jeff is trying/wants to do?).
>
>It is not even possible to provide a single arm binary that runs on
>both armel and armhf.[1] It is a different ABI.
It's *technically* possible for binaries that don't ever pass FP
values as function arguments, but it's really not recommended and
you'd have to fight with the toolchain a lot to do it.
>> The advice here is to instead ship[0] two binaries -- one targetting v5
>> (no neon etc, aka armel in Debian) and another targetting v7 (w/
>> possible(? I forget what is optional) neon and other stuff aka armhf in
>> Debian and other distros).
>
>The main difference between armel and armhf is not the baseline
>(at some point Ubuntu had bumped the armel baseline to v7), the
>main difference is that there is no FPU in the armel baseline.
>Which also means that floating-point parameters must get passed
>in integer registers since there are no floating-point registers
>in the ABI.
Nod.
--
Steve McIntyre, Cambridge, UK. steve@einval.com
We don't need no education.
We don't need no thought control.
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