Writeback Stage

Requirements

Most instructions write the result of some computation or data read from memory into a register. However, the Register File appears in the past stage. Still, the data to be written is only known after the ALU stage or memory stage.

1. Read result from memory stage to Write Data and Write Register from decode stage.

2. Write the result to the register.

Block Diagram

Note that writeback stage has no additional element. We simply route the correct result back to the Register File.