Feature Request: Add SIMDe Library for easy Hardware Architecture independence

[0lhi]

There have been requests to make simple64 compile on other architectures before:

• PPC: https://github.com/simple64/simple64/issues/194
• AMD: https://github.com/simple64/simple64/issues/337

Both were rejected in favor of the advantages that the x86-64-v3 instructions provide.

The SIMDe (SIMD Everywhere) library may provide a solution that aligns with simple64's priorities.

https://github.com/simd-everywhere/simde

Some key points from their README:

• "The SIMDe header-only library provides fast, portable implementations of SIMD intrinsics on hardware which doesn't natively support them"
• "There is no performance penalty if the hardware supports the native implementation (e.g., SSE/AVX runs at full speed on x86, NEON on ARM, etc.)."
• "[I]nstead of forcing you to rewrite everything for each architecture, SIMDe lets you get a port up and running almost effortlessly."
• "There are currently complete implementations of the following instruction set extensions: [...] x86 / x86_64 AVX2[...]"
• "[I]t is important to note that you do not need two separate versions (one using SIMDe, the other native). If the native functions are available SIMDe will use them, and compilers easily optimize away any overhead from SIMDe"

Adding this library would significantly increase the accessibility of the emulator while allowing x86-64-v3 to remain the focus of the development team and main beneficiary of performance tweaks.

[loganmc10]

This does not really apply to how simple64 uses x86-64-v3. Simple64 is compiled using gcc with a target architecture of x86-64-v3, meaning all the C/C++ code is compiled into x86-64-v3 assembly language, this header library won't work around that.