Technique for freeing renamed registers

摘要

Register renaming circuitry for a processing apparatus configured to process a stream of instructions from an instruction set specifying registers from an architectural set of registers. The apparatus including a physical set of registers configured to store data values being processed by the processing apparatus. Register renaming circuitry is configured to receive a stream of operations from an instruction decoder and to map registers that are to be written to by the stream of operations to physical registers within the physical set of registers that are currently available. The register renaming circuitry comprises register release circuitry configured to release the physical registers that have been mapped to the registers when a first set of conditions have been met, and to release the physical registers that have been mapped to the additional registers when a second set of conditions have been met.

主权项

1. Register renaming apparatus for a processing system having a physical set of registers to store data values being processed and in which a stream of instructions from an instruction set is processed, said instructions specifying registers from an architectural set of registers, said register renaming apparatus comprising:
first circuitry configured to receive a stream of operations from an instruction decoder within said processing apparatus and to map registers that are to be written to by said stream of operations to physical registers within said physical set of registers that are currently available and to identify additional registers that are registers that are to be written to by said operations that are not from said architectural set of registers; and second circuitry configured to release physical registers that have been mapped such that they are available for register renaming and to release said physical registers that have been mapped to said registers from said set of architectural registers when a first set of conditions have been met, and to release said physical registers that have been mapped to said additional registers when a second set of conditions have been met, at least some of said conditions within said first set of conditions being different to said conditions within said second set of conditions.