E15: Fundamentals of Digital Systems - Fall 2015 - HOMEWORK 13
1. Download the Verilog code for our example simple CPU from http://www.swarthmore.edu/NatSci/mzucker1/e15_f2014/SimpleCPU.zip and look for the five new CPU instructions added since class.
a. What five instructions were added? Describe how each one works in terms of the source register (or immediate data), destination register, and what operation is being performed.
b. How did the ALU need to get modified to implement these instructions? What is the purpose of the giant nested ?: statement inside the updated ALU module?
2. What bitwise binary operation is being performed by mystery.v ROM locations 2-7? Write pseudocode to illustrate how this particular operation is being performed. Note: You can run this program (or any other one) by modifying the 'include directive inside of E15Process.v. For this particular problem, if you want to view the contents of the registers inside your waveform viewer to determine what's going on, you will likely want to display the results in binary, not decimal.
3. Write a program called triangle.v, similar to fibonacci.v, which instead generates the sequence of triangular numbers, stored in register 3. Include a printout of your triangle.v program along with a printout from your waveform viewer showing a successful run of the program. Please adjust the horizontal scale on your waveform plot to make sure it's clear what's going on inside your program.
4. Difficult: Write a program called rightshift.v. Use ROM location 0 to store a 4-bit initial value into register 0. The remainder of the program, beginning at ROM location 1, should right-shift the value stored in register 0 by one bit, and store the result into register 3 before halting. For instance, if R0 contains the value 4'b1101 at the start of the program, the value 4'b0110 should be stored into R3 when it halts.
Please hand in a printout of your rightshift.v program, along with two printouts of waveform traces demonstrating successful runs of your program on both the input 4'b1101 and the input 4'b1010.
Attachment:- SimpleCPU.zip