Reorder buffer variations
Reorder buffer holds only instruction execution states (results are in rename registers).
- Johnson's description of a reorder buffer in combination with a so-called future file. The future file is similar to the set of rename registers that are separate to the architectural registers.
- In contrast, Smith and Pleskun describe a reorder buffer in combination with a future file, whereby the reorder buffer and the future file receive and store results at the same time.
Other reorder buffer type: The reorder buffer holds the result values of completed instructions instead of rename registers.
Moreover the instruction window can be combined with the reorder buffer to a single buffer unit.