You don't need to be writing assembly. Anything sharing memory between multiple threads could have bugs with ARM's memory model, even if written in C, C++, etc.
replyNot even close. Except maybe in Rust /s
replyFor rustaceans missing that /s, if you just use Relaxed ordering everywhere and you aren't sure why, but hey tests pass on x86, then yeah on arm it may have a problem. On x86 it effectively is SeqCst even if you specify Relaxed.
reply