Method and apparatus for managing register renaming including a wraparound array and an indication of rename entry ages

摘要

A method and apparatus for managing register renaming in an information handling system that supports out-of-order and speculative instruction execution. Register entries are stored in architected registers, and rename entries are stored in rename registers. Register and rename entries are transferred between the rename and architected registers in response to dispatch of instructions or upon the occurrence of a canceling event, such as a mispredicted branch instruction or an interrupt condition. Rename entries are stored in the rename registers in a round robin fashion and tagged by age. Age order of the rename entries is determined without keeping the rename entries in age order through the method of shifting rename entries to the next rename register each time a rename entry is removed from a rename register. By eliminating shifting of rename entries to maintain age order, a power savings is realized.