* Jeff Law via Gcc: > Most targets these days use registers for parameter passing and > obviously we can run out of registers on all of them. The key > property is the size/alignment of the argument differs depending on if > it's pass in a register (get promoted) or passed in memory (not > promoted). I'm not immediately aware of another ABI with that > feature. Though I haven't really gone looking.
I think what AArch64 Darwin does is not compatible with a GCC extension that allows calling functions defined with a prototype without it (for pre-ISO-C compatibility). Given that, anyone defining an ABI in parallel with a GCC implementation probably has paused, reconsidered what they were doing, and adjusted the ABI for K&R compatibility. Thanks, Florian
