On Tue, 9 May 2023 at 15:27, Richard Henderson <richard.hender...@linaro.org> wrote: > > On 5/9/23 13:04, Peter Maydell wrote: > >> If the LDP is aligned mod 8, but not aligned mod 16, then both 8-byte > >> operations must be > >> (separately) atomic, and we return MO_64. > > > > So there's an implicit "at most 2 atomic sub-operations > > inside a WITHIN16 load" restriction? i.e. you can't > > use WITHIN16 to say "do this 8 byte load atomically but > > if it's not in a 16-byte region do it with 4 2-byte loads", > > even though in theory MO_ATOM_WITHIN16 | MO_ATMAX_2 | MO_8 > > would describe that ? > > Correct on both counts. While you're right that this is a valid > generalization, it's not > something for which I've found a use case.
Yeah, that's fine -- but we should note the restrictions/ requirements in the doc comment for WITHIN16. (And maybe an assert somewhere if there's somewhere convenient to put it?) thanks -- PMM
