Need for 4 stages (c’ed)

• Execute

• Write

  • Broadcast on common data bus the value and the tag (reorder buffer number). Reservation stations, if any match the tag, and reorder buffer (always) grab the value.

• Commit

  • When instr. at head of the reorder buffer has its result in the buffer it stores it in the real register (for ALU) or memory (for store). The reorder buffer entry (and/or physical register) is freed.

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