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Re: Does ARMEL toolchain include NEON support?

On Thu, Feb 28, 2019 at 01:36:33PM -0500, Jeffrey Walton wrote:
>On Thu, Feb 28, 2019 at 1:18 PM Wookey <wookey@wookware.org> wrote:
>> On 2019-02-28 09:05 +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?).
>> Just to clarify: it's not possible to built a binary which works at
>> all on both armel and armhf. They are different ABIs ('architectures'
>> in Debian terminaology). Modulo things like qemu emulation or other
>> very carefully constructed binaries a binary is one ABI or the other,
>> working together with others on that basis. There are then separate
>> questions of what base ISA (instruction set) it is built to (v5, v7),
>> and to what degree it requires/supports optional features of the
>> hardware/ABI (neon, fpu, maverick etc).
>Forgive my ignorance...
>Is it possible to support both at a project's ABI level in C/C++ by
>avoiding floats and doubles in function signatures?

Basically, no. The toolchains are set up to explicitly set flags to
state which ABI a binary is targeting. It's not possible to say

Steve McIntyre, Cambridge, UK.                                steve@einval.com
"This dress doesn't reverse." -- Alden Spiess

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