Hi Al,

aarch64 is a 64 bit mode for ARM CPUs, which use the NEON instructions.
They are not compatible with AVX/AVX2, which is an instruction set for
x86.  The CMake build system has options for different SIMD options:

  https://github.com/drowe67/LPCNet/blob/master/CMakeLists.txt

As a first step, try to build LPCNet by itself (with NEON) and run the
command line tests.

I worked on the optimisation of the LPCNet code for the RPi, and struggled:

  http://www.rowetel.com/?p=6577

I think Jean-Marc's pushed it a little further fwd since then, but last
I heard it won't run on a Pi-class machine in real time.

Have fun.

- David

On 24/06/19 07:14, Al Beard wrote:
> 
> Hi all,
> 
> I notice when looking through the LPCNet code that it uses, on x86_64,
> it uses
> "intrinsics" to use the AVX/AVX2 extended instructions in modern CPUs.
> 
> I'm not a "super guru" C or C++ programmer. How "compatible" are the
> x86_64 and the aarch64 "intrinsics" ?
> 
> On the aarch64 box here, (NetBSD) where I'm told "it just works" I do have:
> /usr/include/gcc-7/arm_neon.h
> 
> And, from /proc/cpuinfo "neon" is there so I hope the kernel knows what
> to do
> during context switching. (Do I have the right terminology here?)
> (I assume there's only one SIMD/NEON unit on the SoC.)
> 
> BTW: We've just done the Winter VHF/UHF (and Microwave) contest.
> We had 6m to 23cm with Yaesu/Icom transceivers.
> And, 10Ghz and 24Ghz transverters, two sites 3km apart 59 both ways.
> On 122GHz it was a LOT harder. We could do CW as the setup, a mixer diode
> at the focus of a cassegrain dish, it can triple but to do SSB (or FM)
> the output
> is some 15db down. The diode is microscopic on a thin PCB about 10mm x 15mm.
> 
> Also, our atmosphere has huge absorption around this frequency, water
> related??
> (Is this why we have this band??)
> 
> Anyway, CW succeeded, just. very "wobbly" signals.
> 
> 
> Alan VK2ZIW
> 
> 
> 
> 
> 
> 
> 
> 
> ---------------------------------------------------
> Alan Beard
> 
> OpenWebMail 2.53
> 
> 
> 
> 
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