On 27/06/17 23:53, Richard Earnshaw wrote: > This is correct. AArch64 cannot do the 16-byte atomic compare and swap > and needs lock operations. I may be completely wrong, but I think it can. ARM (32-bit) supported double-word LL/SC from arm6k and armv8 I think had it from day one. CAS is mapped onto LL/SC. I've written asm to do this, the key is the ldxp and stxp instruction, and it seems to work.
