[hint] sse2neon

[ReneKeilwerth]

even if there is no plan to implement arm-instructions, it is moslty possible to use the sse2neon lib to emulate sse instructions on ARM.
So you can use vectorclass on ARM

i found some things to be defined before including the vectroclass.h
and a small change that has to be made to the instrset.h file.

it is working as far as i could test on apple M1 chips

maybe those changes can be directly applied to vectorclass due to a preprocesse like "VCL_USE_SSE2NEON"

cheers

---

/*
ARM compatible include of the vectorclass

on ARM/MAC the sse2neon lib will be imported
and some parameters for the vectorclass are prepared.

#IMPORTANT in vectorclass.h->instrset.h the cpuid function must be
hidden, since it is not compatible with ARM-compilers.

if missing, add the header-include check #if !defined(SSE2NEON_H)
to the function to hide it when compiling on ARM

remember that a dispatcher is not possible in this case.

*/

#if __arm64
#include <sse2neon.h>

// limit to 128byte, since we want to use ARM-neon
#define MAX_VECTOR_SIZE 128

//limit to sse4.2, sse2neon does not have any AVX instructions ( so far )
#define INSTRSET 6

//define unknown function
#define _mm_getcsr() 1

//simulate header included
#define __X86INTRIN_H
#endif
// finally include vectorclass
#include <vectorclass.h>

[AgnerF]

Thank you for your suggestion.
I don't want to include any support for ARM in the vector class library because I have no access to test it. All functions have to be tested thoroughly in all possible configurations. I have automated test scripts that make thousands of tests for all possible configurations and compilers on x86. Making similar tests for ARM would be a lot of work and would undoubtedly reveal a lot of problems. I think it would be better to make a separate version of VCL for ARM, but somebody else will have to do this.