On 29/06/17 11:28, Andrew Haley wrote: > I think I now properly understand Richard Earnshaw's point: that we > *do* support a full set of atomic primitives for 16-byte types via > libatomic, but for them to work as a sequentially-consistent set we > must use the same locking scheme for all of them. It's ugly, and > horrible for anyone who simply wants a double-word CAS, but it is what > it is. We can't use LDXP because it isn't atomic on its own, and the > ARM manual is quite explicit about this. Anyone who wants to use > a real compare-and-swap-16 is on their own. I may be utterly, utterly wrong, but I think what's happened makes perfect sense at each step of the way but has led to an outcome which is crazy. I publish a lock-free data structure library and I must specifically avoid libatomic.
