MECHANISM TO PRECLUDE LOAD REPLAYS DEPENDENT ON OFF-DIE CONTROL ELEMENT ACCESS IN OUT-OF-ORDER PROCESSOR

摘要

An apparatus includes first and second reservation stations. The first reservation station (421.L) dispatches a load micro instruction, and indicates on a hold bus (444) if the load micro instruction is a specified load micro instruction directed to retrieve an operand from a prescribed resource other than on-core cache memory. The second reservation station (421.1-421.N) is coupled to the hold bus (444), and dispatches one or more younger micro instructions therein that depend on the load micro instruction for execution after a number of clock cycles following dispatch of the first load micro instruction, and if it is indicated on the hold bus (444) that the load micro instruction is the specified load micro instruction, the second reservation station (421.1-421.N) is configured to stall dispatch of the one or more younger micro instructions until the load micro instruction has retrieved the operand. The plurality of non-core resources includes a control element, coupled to the out-of order processor via a control bus.