StormNalinHW12

.pdf

School

Northeastern University *

*We aren’t endorsed by this school

Course

2322

Subject

Electrical Engineering

Date

Feb 20, 2024

Type

pdf

Pages

3

Uploaded by BailiffOxideAntelope36

Report
Nalin Storm EECE 2322 Digital Design & Computer Organization Homework 12 Question 1. Suppose one of the following control signals in the multi-cycle RISC-V processor has a stuck-at-0 fault, meaning that the signal is always 0 regardless of its intended value. What instructions (R-Type, lw, sw, beq) would malfunction for each case? Why? Refer to the multicycle datapath and control signals discussed in class. (a) RegWrite: sw and beq instructions would not malfunction, while lw and R-Type would since RegWrite for lw and R-Type (for AluWriteBack) instruction must be 1. (b) PCUpdate: All instructions would malfunction since State S0 – Fetch is used for all instructions and requires PCUpdate to equal 1. (c) Branch: Only beq would malfunction since beq is the only instruction that requires Branch to equal 1. (d) AdrSrc: lw and sw would malfunction since those are the only instructions that require AdrSrc to equal 1. (e) MemWrite: sw would malfunction since it’s the only instruction that requires MemWrite to equal 1. (f) IRWrite: All instructions would malfunction since State S0 – Fetch is used for all instructions and requires IRWrite to equal 1. Question 2. Consider the following code that is executed on the multi-cycle RISC-V processor described in class.
1. How many clock cycles are required to run this program? add = 4, addi = 4, slt = 4, beq = 3, jal = 4, 55 total instructions add + add + addi + 10*(slt + beq + add + addi + jal) + slt + beq 4 + 4 + 4 + 10 *(4 + 3 + 4 + 4 + 4) + 4 + 3= 209 clock cycles required The program is considered ended when it branches to “done:” True 1. What is the average Cycles Per Instruction (CPI) of this program? Instruction Type Probability R-Type 4/8 addi 2/8 Beq 1/8 jal 1/8 CPI = 4/8 * 4 + 2/8 * 4 + 1/8 * 4 + 1/8 * 3 = 3.875 2. What is the execution time of the Program on a multi-cycle datapath with a clock cycle time of 375ns (375 x10 –9 s)? Show all your calculations. T ex = I x CPI x T cycle = 55 x 3.875 x 375 x 10 -9 = 7.9921875 x 10 -5 seconds Question 3. Suppose the multicycle RISC-V processor has the component delays given in the Table discussed in class and available in the notes. Alyssa P. Hacker designs a new register file that has 40% less power but twice as much delay. Should she switch to the slower but lower power register file for her multicycle processor design? Explain why. Doubling the register file interaction time for the purpose of 40% less power would increase the MemWriteBack cycle time, and the AluWriteBack cycle time. The MemWriteBack cycle time would increase from 155 to 215 and the AluWriteBack cycle time would increase from 155 to 215 as well. Since neither of these states are included in the total Tcycle time, increasing the register file interaction time would not affect the total Tcycle time. Therefore, Alyssa should switch to the slower but lower power register file since the slower register file will not effect the total Tcycle time.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help