> The good news is that it is very easy to write assembly which targets Apple’s computers as well as the other 64-bit ARM devices running operating systems other than Darwin.
And completely ignoring PE and Windows on ARM.
x18 is "the platform register", reserved for the OS. The ISA manual says not to touch it unless you know what you're doing. Also, I don't know but I could believe that android and non-googly linux use different ABIs (but probably not because everyone uses pretty much the same ABI on aarch64 from what I've seen), but surely Alpine is linux and has the same ABI as other linuxes.
But basically it's similar to elf vs coff. windows also uses several modern alignments and a shadow stack to make life easier. But arm has so much more scratch registers, much more fun.
