For the new hazard detection unit from 4.21.5, specify which output signals it asserts in each of the first five cycles during the execution of this code.

Problem 4.21.5

If there is no forwarding, what new inputs and output signals do we need for the hazard detection unit in Figure 4.60? Using this instruction sequence as an example, explain why each signal is needed.

This exercise is intended to help you understand the relationship between forwarding, hazard detection, and ISA design. Problems in this exercise refer to the following sequences of instructions, and assume that it is executed on a 5-stage pipelined datapath:

PCWrite PC Instruction memory IF/DWrite IF/ID Instruction Hazard detection unit Control Registers MUX IF/ID. RegisterRs IF/ID. RegisterRt IF/ID. RegisterRt IF/ID. RegisterRd ID/EX.RegisterRt ID/EX.MemRead ID/EX WB M EX Rt Rd. Rs Rt MUX MUX u MEX EX/MEM WB ALU Forwarding unit M Data memory MEM/WB WB MUX