Issue and Dispatch
The notion of the instruction window comprises all the waiting stations between decode (rename) and execute stages.
The instruction window isolates the decode/rename from the execution stages of the pipeline.
Instruction issue is the process of initiating instruction execution in the processor's functional units.
- issue to a FU or a reservation station
- dispatch, if a second issue stage exists to denote when an instruction is started to execute in the functional unit.
The instruction-issue policy is the protocol used to issue instructions.
The processor's lookahead capability is the ability to examine instructions beyond the current point of execution in hope of finding independent instructions to execute.