I'm the wrong guy to answer this but I believe the ports are available to one pipeline, so no independent pipelines, but instructions behind the 'head' can hop

I'm the wrong guy to answer this but I believe the ports are available to one pipeline, so no independent pipelines, but instructions behind the 'head' can hop over the head if the head is stalled, if there are execution units free. Instructions can get reordered, over quite a wide window, something like 200 instructions (look up the reorder buffer, ROB, although there's another windows which affects this, something to do with retiring instructions). <https://en.wikipedia.org/wiki/Re-order_buffer> https://en.wikipedia.org/wiki/Re-order_buffer> Come to think of it, I don't know how the ports are used. I am entirely unqualified to answer this question :)