Scoreboard for scheduling of instructions in a microprocessor that provides out of order execution

摘要

A system and method for scheduling instructions that are executed in the microprocessor are provided. The microprocessor executes multiple instructions per cycle that may have dependencies on execution results of other instructions. A scoreboard is utilized to schedule instructions. The scoreboard indicates dependencies between instructions. The scoreboard also controls the indication of dependencies based on the issuance of old instructions. The scoreboard includes a register for each instruction. The register has elements each of which corresponds to one of other instructions. An element of the register for an instruction is set where the element corresponds to one of other instructions which the instruction depends on.