Final Exam Study Guide

Here is a list of some of the types of questions you might encounter on the final. Best of luck!

Exams are closed book except for half page, single-sided of notes (i.e., half of 8.5" x 11"). The exam will focus on material covered since the midterm.

1. Given specific values in specific registers and memory addresses and a specific assembly instruction (e.g., mov, lea, push, pop, arithmetic), determine what the effect of the instruction is on the stack pointer, on the stack contents, and on the contents of registers.
2. What is the difference between the lea and mov instructions?
3. Given a piece of code with an expression omitted and given the corresponding assembly code, fill in the missing expression.
4. What is the result of a given sub instruction?
5. What is the result of a given shift instruction?
6. Given a particular action, can you properly form the assembly instruction to accomplish a particular action?
7. Given a particular instruction, consider each of the operands and determine whether the instruction is moving to/from immediate (i.e., constant), memory, or register.
8. Looking at the assembly for a simple procedure, what purpose does a particular instruction serve in the context of that procedure?
9. What is a callee-saved register? Where within the set of instructions encoding a procedure would you expect to see a callee-saved register saved? Where would you expect to see if restored? Same question but with reference to caller-saved registers.
10. What all is done when the call assembly instruction executes? How about the ret instruction?
11. What is the byte code for the ret instruction?
12. What functions do each of the following registers conventionally serve? %rdi, %rsi, %rdx, %rsp, %rip, %rax
13. What is needed for a code injection attack to work? What safety measures do modern operating systems use to prevent code injection attacks?
14. How do return-oriented programming (ROP) attacks work? What safety measures are taken to prevent these types of attacks?
15. Given a pair of instructions encoding a conditional move or jump, can you articulate under what conditions the move or jump will and will not occur?
16. What is block pipelining, what types of assembly instructions pose a challenge to block pipelining, and why? What advantage does a conditional move have over a conditional jump?
17. Given a piece of assembly code encoding a loop, which type of loop is most-likely represented: do-while, while (jump-to-the-middle), while (guarded do-while), or a for loop?
18. At a high-level, what is a jump table, and how does it work in the context of implementing a switch statement?
19. What instructions are used to pass control to/from procedures? to pass data to/from procedures?
20. Where is the stack located in memory? Which way does it grow? What exactly do the push and pop instructions do?
21. Describe how the memory hierarchy is structured. Where in the hierarchy do we find memory that is faster? larger? costlier? slower? smaller? cheaper?
22. How/why do caches work?
23. What is meant by the term abstraction? Encapsulation?
24. How specifically are the first 6 arguments passed to a function? If a function requires more than 6 arguments, how are these arguments passed?
25. What all might one expect to find in a stack frame for a procedure? What one might not expect to find in a stack frame for a procedure?
26. What is a pointer? What types of values can a pointer have? How many bytes are in an address on a 64-bit machine?
27. In what order is the data stored in 2D matrices stored in memory? Row-major or column-major? What does this mean? How is the address for a particular element in a matrix calculated as a function of the number of rows, the number of columns, and the size of an element in the matrix?
28. What is meant by a stride-k reference pattern? What is the stride reference pattern for a given piece of code? How should the loops be ordered in order to achieve a stride-1 reference pattern for a particular piece of C code?
29. What do we mean by the principle of locality? What is spatial locality? What is temporal locality? How are each exhibited in a particular piece of code?
30. What special considerations are required in order to implement recursion?
31. What expressions are equivalent to the name of an array? (i.e., recognizing that the name of an array is equivalent to the address of its 0th element.)
32. What is a linked list? How is a typical linked list node struct structured?
33. Given a struct definition, what would be a correct alignment for the structure?
34. Considering the way alignment is enforced, which of the following ordering of struct instance variables would be the most efficient in terms of saving space?
35. Which functions are safe/not safe and why: fgets, gets, strncpy, strcpy, scanf with %s specifier
36. As regards a cache read, an address consists of what subelements? Given an address and a diagram of a cache, can you identify the corresponding element?
37. Direct-mapped cache vs associative cache
38. No questions on disk anatomy, computing disk capacity, or disk access time
39. No questions about support for oct words.
40. No questions about floating point registers or instructions.