AGE-BASED MANAGEMENT OF INSTRUCTION BLOCKS IN A PROCESSOR INSTRUCTION WINDOW

摘要

A processor core in an instruction block-based microarchitecture includes a control unit that explicitly tracks instruction block state including age or priority for current blocks that have been fetched from an instruction cache. Tracked instruction blocks are maintained in an age-ordered or priority-ordered list. When an instruction block is identified by the control unit for commitment, the list is checked for a match and a matching instruction block can be refreshed without re-fetching from the instruction cache. If a match is not found, an instruction block can be committed and replaced based on either age or priority. Such instruction state tracking typically consumes little overhead and enables instruction blocks to be reused and mispredicted instructions to be skipped to increase processor core efficiency.