Am 2014-12-16 03:54, schrieb ron minnich:
Notwithstanding the merits of the idea, does anyone know if this is doable or I am just misremembering?
Since even LOCK REP ... is not allowed, I think you're misremembering. LOCK provides atomicity guarantees for the single instruction it covers, nothing else.
What's typically used in situations like your example is cmpxchg: load the value, copy it, modify, then atomically exchange ram and register content. compare exchanged value with copy to make sure there was no interference, otherwise restart.
Patrick