> i don't remember seeing any wording relating to mixed-size accesses in the intel manual (not withstanding that the official models are ... ambiguous, to say the least, compared with what 3rd-party researchers have done)
I was probably misremembering the details. The manual has to say this regarding #LOCK prefixed operations:
"Software should access semaphores (shared memory used for signalling between multiple processors) using identical addresses and operand lengths. For example, if one processor accesses a semaphore using a word access, other processors should not access the semaphore using a byte access"
which is already vague enough, but regarding general atomic load and stores I couldn't find anything.
I was probably misremembering the details. The manual has to say this regarding #LOCK prefixed operations:
"Software should access semaphores (shared memory used for signalling between multiple processors) using identical addresses and operand lengths. For example, if one processor accesses a semaphore using a word access, other processors should not access the semaphore using a byte access"
which is already vague enough, but regarding general atomic load and stores I couldn't find anything.