| 摘要 |
A processor employs ordering dependencies for load instruction operations upon store address instruction operations. The processor divides store operations into store address instruction operations and store data instruction operations. The store address instruction operations generate the address of the store, and the store data instruction operations route the corresponding data to the load/store unit. The processor maintains a store address dependency vector indicating each of the outstanding store addresses and records ordering dependencies upon the store address instruction operations for each load instruction operation. Accordingly, the load instruction operation is not scheduled until each prior store address instruction operation has been scheduled. Store addresses are available for dependency checking against the load address upon execution of the load instruction operation. If a memory dependency exists, it may be detected upon execution of the load instruction operation. The processor may also employ an instruction queue and dependency vectors therein which allow a flexible dependency recording structure. The dependency vector includes a dependency indication for each instruction queue entry, which may provide a universal mechanism for scheduling instruction operations. An arbitrary number of dependencies may be recorded for a given instruction operation, up to a depdendency upon each other instruction operation. Since the dependency vector is configured to record an arbitrary number of dependencies, a given instruction operation can be ordered with respect to any other instruction operation. Accordingly, any architectural or microarchitectural restrictions upon concurrent execution or upon order of particular instruction operations in execution may be enforced. The instruction queues evaluate the dependency vectors and request scheduling for each instruction operation for which the recorded dependencies have been satisfied.
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