feat: add s390x architecture support

[iko1]

Fixes #939

[iko1]

The following lines should be added to the file 'helio/cmake/internal.cmake' to compile the project to s390x architecture:

elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "s390x")
set(MARCH_OPT "-march=native")
set(COMPILE_OPTS "${COMPILE_OPTS} -mzvector")

[romange]

hey, have you tested this function?
according to the docs https://doc.rust-lang.org/beta/core/arch/x86_64/fn._mm_movemask_epi8.html

_mm_movemask_epi8 returns the mask of msb bits (0x80). you do something else, IMHO.
Also, if you use scalar code here, there is no point in duplicating exactly the same logic really.

for (int i = 0; i < 16; i++) {
    if (has_error[i] & 0x80) 
      return false;
}

[chakaz]

May I suggest modifying sse_port.h to #include <vecintrin.h> instead of relying on the files including it?

[iko1]

I'm sure after the change you suggested, something will break in the tests, so I suggest taking your suggestion to another PR.

[chakaz]

I feel like I need to explain my proposal, which really is a minor one:
Currently there are 2 files that #include "core/sse_port.h". In your PR, you are first checking if the platform is s390x, and if so you do not include sse_port.h but include <vecintrin.h> instead. My proposal is to change sse_port.h to check which platform it is, and #include <vecintrin.h> if relevant.
This is a compilation change, so as long as it builds on all platforms it should not affect tests, right?
Is there anything that I'm missing?

[iko1]

Done.
The filename 'sse_port.h' is misleading because SSE is x86 technology. Can I rename the filename to 'simd_port.h'?

[chakaz]

Thanks for your contribution!