Final Test: Computer Architecture
The grade formula is as follows:
Grade = 0.4 * Theory + 0.6 * Programming
Part 1. Theoretical Questions
Answer the theoretical questions in a few sentences (1-2 paragraphs for a question).
Use your own words. Copy-paste from external sources and other students will result in 100% penalty.
-
Describe how integer and floating-point values are represented in the binary format: unsigned integers, 2’s complement signed integers, and single-precision floating-point. Why floating-point exponents are biased? What is the difference between integer sign- and zero-extension? What is integer overflow? What are floating-point overflow and underflow?
-
Describe the concept of pipeline. List the 5 stages and give brief descriptions for them. What pipeline hazards are? List the types of hazards and the ways to prevent them (with brief definitions). Give an example of a hazard situation and how it can be handled. What is branch prediction is needed for? How the loop unrolling optimisation can help improve pipeline performance?
-
Give a brief description of how caching mechanism works (block, index, tag, valid bit, dirty bit). Give the definition of associativity (direct-mapped, set associative, fully associative). What is the difference between write-through and write-back? What is replacement policy (what type of policy do you know)? How many cache levels are typical for modern processors? What problem can caches create for multicore processors?
Part 2. Programming Task
Write a RISC-V assembly program that inputs integer value x (assumed non-negative)
and calculates the value of the f(x) mathematical function according to the specified equations.
f(x) must be implemented as a function and must comply with RISC-V calling conventions.
The implemented function must use callee-saved registers (s0, s1, etc.) to
store intermediate results of calculations.
These registers must be saved to the stack and restored when the function returns.
The f(x) function is as follows (this is an example, find your variant below):
f(x) = -2 if x < 1
f(x) = 8 * x**8 + 1 * x**5 - 6 * x**3 - 1 * x if x >= 1
f(x) = 8**x + 4 if x == 3
f(x) = -3 * x + -10 if x > 9
Variants
Choose your variant number according to your number in your group. See the lists of students here.
Variants for groups: