EXERCISE 41725 10 Consider the following loop LOOP LDUR X 10 X 1 0 quadLDUR X 11 x 1 8 quadADD x 12 X 10 X 11 quadSUBI x 1 x 1 16 quadCBNZ X12 LOOP Assume that perfect branch prediction is used no...

#### Solution By Steps ***Step 1: Create Pipeline Diagram for First Iteration*** Construct a pipeline diagram for the first iteration of the loop. Each instruction goes through the stages of Instruction Fetch (IF), Instruction Decode (ID), Execute (EX), Memory Access (MEM), and Write Back (WB). Since there's perfect branch prediction and full forwarding support, we can overlap instructions without stalls for control hazards. ***Step 2: Create Pipeline Diagram for Second Iteration*** Extend the pipeline diagram to include the second iteration of the loop, taking into account the overlap of instructions due to the pipeline. ***Step 3: Identify Non-useful Work Stages*** Mark the stages in the pipeline where no useful work is being done. This typically occurs when an instruction is waiting for a previous instruction to complete a stage that it needs to proceed. ***Step 4: Count Cycles with All Stages Doing Useful Work*** Count the number of cycles where all five stages of the pipeline are doing useful work, starting from when the SUBI instruction is in the IF stage until the CBNZ instruction of the first iteration is in the IF stage. #### Final Answer Due to the limitations of this text-based format, I cannot draw a visual diagram. However, I can describe the pipeline execution: 1. LDUR X10 starts in IF and proceeds through the pipeline stages in subsequent cycles. 2. LDUR X11 can start in IF the cycle after LDUR X10 starts. 3. ADD X12 can start in IF the cycle after LDUR X11 starts, with no stall because of full forwarding. 4. SUBI X1 can start in IF the cycle after ADD X12 starts, with no stall because of full forwarding. 5. CBNZ X12 can start in IF the cycle after SUBI X1 starts, with no stall due to perfect branch prediction. For the second iteration, the instructions will follow the same pattern, with each starting in the IF stage immediately after the previous instruction starts its ID stage. The cycles with all stages doing useful work would be those after the pipeline is fully ramped up until the first instruction of the next iteration enters the IF stage, which would be when the SUBI instruction is in the MEM stage. #### Key Concept Pipeline Efficiency #### Key Concept Explanation Pipeline efficiency refers to the ability of the pipeline to perform instruction processing with minimal stalls or idle cycles. In a fully efficient pipeline, every stage of the pipeline would be performing useful work in every cycle, maximizing throughput.