Two principal techniques to implement renaming
Separate sets of architectural registers and rename (physical) registers are provided.
- The physical registers contain values (of completed but not yet retired instructions),
- the architectural (or logical) registers store the committed values.
- After commitment of an instruction, copying its result from the rename register to the architectural register is required.
Only a single set of registers is provided and architectural registers are dynamically mapped to physical registers.
- The physical registers contain committed values and temporary results.
- After commitment of an instruction, the physical register is made permanent and no copying is necessary.
Alternative to the dynamic renaming is the use of a large register file as defined for the Intel IA-64 (Itanium).