A message exchange system for software components on different processors. A first component's attempt to load a write register with a message pointer (or a message itself) triggers a determination whether space exists in a shared memory queue. If so, the queue is updated by incrementing a message counter, writing the message/pointer into the queue where designated by a write pointer, and changing the write pointer to a next queue location. A second component's attempt to load the message/pointer from a read register triggers a determination whether there is at least one new message in the queue. If so, the queue is updated by decrementing the message counter, reading the message/pointer from the queue where designated by a read pointer, and changing the read pointer to point to a next queue location. The determinations and queue updates are performed atomically with respect to the software components.