Aims
to give you experience writing MIPS assembly code to give you experience translating C to MIPS to give you experience with data and control structures in MIPS
Getting Started
Create a new directory for this assignment called breakout, change to this directory, and fetch the provided code by running these commands:
If you’re not working at CSE, you can download the provided files as a zip file or a tar file.
This will add the following files into the directory:
breakout.s: a stub MIPS assembly file to complete. breakout.c: a reference implementation of Breakout
in C. breakout.simple.c: a copy of the reference implementation of Breakout, for you to simplify. input.txt:
example input file. breakout.mk: a make fragment for compiling breakout.c. Breakout: The Game breakout.c is an implementation of a version of Breakout, a popular and influential video game.
An example game of Breakout can be seen to the right.
A game of Breakout takes place on a 2D grid, where the player must move a paddle to bounce a ball (*) into a group of bricks
(digits).
You can move the paddle left ( a and A ) and right ( d and D ).
1521 mipsy breakout.s
Welcome to 1521 breakout! In this game you control a paddle (—) with the a and d (or A and D for fast movement) keys, and your goal is to bounce the ball (*) off of the bricks
(digits). Every ten bricks destroyed spawns an extra ball. The . key will advance time one step. Enter the width of the playing field: 12
SCORE: 0
==============
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|000111222333|
|000111222333|
|000111222333|
|000111222333|
|000111222333|
|000111222333|
| |
| |
| * |
| —— |
>> ;
SCORE: 5
==============
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|000111222333|
|000111222333|
|000111222333|
|000111222333|
|000111222333|
|000 222333|
| * |
| |
| |
| —— |
>> q
Hitting bricks with the ball will destory the bricks, and reward the player with score points. Every 10 bricks destroyed will spawn a new ball, with up to 3 balls on the screen at any given time.
If a ball leaves the bottom of the screen then it is destroyed, and if there are no more balls left the game ends.
To get a feel for this game, try it out in a terminal:
You should read through breakout.c. There are comments throughout it that should help you understand what the program is doing [citation needed] — which you’ll need for the next part of the assWeChat: cstutorcsignment. breakout.s: The Assignment
Your task in this assignment is to implement breakout.s in MIPS assembly.
You have been provided with some assembly and some
helpful information in breakout.s. Read through the provided code carefully, then add MIPS assembly so it executes exactly the same as breakout.c.
The functions run_command, print_deubg_info and print_screen_updates have ahttps://tutorcs.comlready been translated to MIPS assembly for you.
You have to implement the following functions in MIPS assembly:
print_welcome main read_grid_width game_loop
initialise_game move_paddle count_total_active_balls print_cell register_screen_update count_balls_at_coordinate print_game spawn_new_ball move_balls move_ball_in_axis hit_brick
check_ball_paddle_collision move_ball_one_cell
You must translate each function separately to MIPS assembler, following the standard calling conventions used in lectures. When translating a function, you must not make any assumptions about the behaviour or side effects of any other function which is called.
Subsets
This assignment is split into four subsets. Later subsets will involve more complex translation.
Subset Functions Performance Weight
print_welcome
Subset 0 10%
main read_grid_width game_loop initialise_game
Subset 1 45% move_paddle
count_total_active_ballsWeChat: print_cell register_screen_update
count_balls_at_coordinateAssignment
Project Exam Help
Subset 2 print_game 25% spawn_new_ball
move_balls
move_ball_in_axis hit_brick
Subset 3
Commands 20% check_ball_paddle_collisionQQ: 749389476 move_ball_one_cell
Command Description Function called
a Move the paddle one cell left move_paddle
d Move the paddle one cell right move_paddle
A Move the paddle three cells left move_paddle
D Move the paddle three cells right move_paddle
. Simulate the movement of the ball(s) move_balls
; Simulate the movement of the ball(s) for 3 steps move_balls
, Simulate the movement of the ball(s) for ⅓ of a step move_balls
? Output the internal state of the game print_debug_info
h Output the welcome message print_welcome
s Output changes to the screen (used by play-breakout) print_screen_updates
p Print the game, and turn off auto-printing print_game
q Quit the game —
Running & Testing
To run your MIPS code, simply enter the following in your terminal:
1521 mipsy breakout.s
Once you have finished your translation, to test your implementation, you can compile the provided C implementation, run it to collect the expected output, run your assembly implementation to collect observed output, and then compare them.
The game takes a lot of input, so it’s a good idea to write a file with the input you want to test, and then pipe that into your program.
You have been given a file called input.txt as an example.
dcc breakout.c -o breakout cat input.txt | ./breakout | tee c.out
cat input.txt | 1521 mipsy breakout.s | tee mips.outWeChat: diff -s c.out mips.out
Files c.out and mips.out are identical
? command (which calls print_debug_info) to be useful.
Hints
You should implement all the functions from one subset before moving on to the next.
Simplified C code
You are encouraged to simplify your C code to remove any loop constructs and if-else statements, and test that your simplified code works correctly before translating it to MIPS, in a separate file breakout.simple.c.
This file will not be marked – you do not need to submit it.
In order to allow you to check that your simplified code works correctly, we have provided a simple set of automated tests.
You can run these tests by running the following command:
An example game of Breakout
Assumptions, Clarifications, and Restrictions
Like all good programmers, you should make as few assumptions as possible.
Your functions will be tested individually. They must exactly match the behaviour of the corresponding C function and they must follow MIPS calling conventions.
The C code defines constants using #define. Your MIPS translation should use the corresponding provided named constants, in the places where a #define is used in the C code. You should not use a #define constant in your MIPS translation if it is not used in the corresponding part of the C code.
There will be a correctness penalty for assignments that do not follow standard MIPS calling conventions including:
Function arguments are passed in registers $a0..$a3.
Function return values areWeChat: passed in register $v0
Values in registers $s0..$s7 are preserved across function calls. If a function changes these registers, it must restore the original value before returning.
The only registers’ values that can be relied upon across a function call are $s0..$s7, $gp, $sp, and $fp. All other registers must be assumed to be have, an undefined value after a function call, except $v0 which has the function return value.
If you need clarification on what you can and cannot use or do for this assignment, ask in the class forum.
You are required to submit intermediate versions of your assignment. See below for details. Breakout wrapper
You can change the parameter 60 to other numbers for different grid widths. You can also optionally supply another parameter slow, medium (which is the default), fast or increasing to alter the game speed. For example, this will start a game with fast speed and a grid width of 42:
Change Log
Assessment
Testing
We have provided some autom ated tests to help you check the correctness of your translation.
To run all the provided tests, execute the following command:
1521 autotest breakout
Some of these tests check only a specific function, and some test your whole program. To run all the tests for a specific function, pass the name of the function to autotest. For example, to run all the tests for the print_welcome function, run the command:
1521 autotest breakout print_welcome
You can also run all the autotests for a particular subset. For example, to run all the autotests for subset 1, run the command:
To run the autotests which test your program as a whole, run the command: 1521 autotest breakout whole_prog
Some tests are more complex tAssignment Project Exam Helphan others. If you are failing more than one test, you are encouraged to focus on solving the first of those failing tests. To do so, you can run a specific test by giving its name to the autotest command:
1521 autotest breakout print_welcome_S0
Whilst we can detect that errors have occurred, it is often substantially harder to explain what that error was.
The errors from 1521 autotest will be less clear and useful than in labs. You will need to do your own debugging and analysis.
1521 autotest will not test everything. You are strongly encouraged to do your own testing. The provided autotests are less comprehensive for latehttps://tutorcs.comr subsets.
Whilst the function autotests for subset 0, 1 and 2 check for your conformance to the MIPS calling convention (‘strict’ autotests), the subset 3 autotests will not check whether your code follows the MIPS calling convention. However, the marking tests will check for conformance to the MIPS calling convention. This means that it is important that you check yourself that your code follows the MIPS calling convention, particularly for your subset 3 code.
Submission
When you are finished working on the assignment, you must submit your work by running give:
You can run give multiple times.
Only your last submission will be marked.
You can check your latest submission on CSE servers with:
You can check the files you have submitted here.
The UNSW standard late penalty for assessment is 5% per day for 5 days – this is implemented hourly for this assignment.
For example, if an assignment worth 60% was submitted half an hour late, it would be awarded 59.8%, whereas if it was submitted past 10 hours laWeChat: cstutorcste, it would be awarded 57.8%.
Assessment ScheEmail: [email protected]
An indicative assessment scheme for performance follows.
100% for performance implements all behaviours perfectly, following the spec exactly.
85% for performance implements all simple and most difficult functions correctly.
65% for performance implements all simple and some moderate difficulty functions correctly.
≤ 50% for performance good progress, simple functions work correctly.
An indicative assessment scheme for style follows.
100% for style perfect style
90% for style great style, almost all style characteristics perfect.
80% for style good style, one or two style characteristics not well done.
70% for style good style, a few style characteristics not well done.
60% for style ok style, an attempt at most style characteristics.
≤ 50% for styl n attempt at style.
An indicative style rubric follows.
Formatting (8/20):
Whitespace
Indentation (consistent, tabs or spaces are okay)
Line length (below 120 characters unless very exceptional)
Line breaks (using vertical whitespace to improve readability)
Documentation (12/20): :
Header comment (with name, zID, description of program)
Function comments (above each function with a description) Sensible commentingAssignment Project Exam Help throughout the code
0 for knowingly providing your work to anyone assignment 1 and it is subsequently submitted (by anyone).
0 FL for submitting any other person’s work; this includes joint work. COMP1521
academic https://tutorcs.comsubmitting another person’s work without their consent; misconduct paying another person to do work for you.
Intermediate Versions of Work
You are required to submit intermediate versions of your assignment.
Every time you work on the assignment and make some progress you should copy your work to your CSE account and submit it using the give command above. It is fine if intermediate versions do not compile or otherwise fail submission tests. Only the final submitted version of your assignment will be marked.
Assignment Conditions
Joint work is not permitted on this assignment.
Do not request help from anyone other than the teaching staff of COMP1521 — for example, in the course forum, or in help sessions.
Do not post your assignment code to the course forum. The teaching staff can view code you have recently submitted with give, or recently autotested.
Assignment submissions are routinely examined both automatically and manually for work written by others. Rationale: this assignment is designed to develop the individual skills needed to produce an entire working program. Using code written by, or taken from, other people will stop you learning these skills. Other CSE courses focus on skills needed for working in a team.
The use of code-synthesis tools, such as GitHub Copilot, ChatGPT, Google Bard, etc. are not permitted on this assignment.
Rationale: this assignment is designed to develop your understanding of basic concepts. Using synthesis tools will stop you learning these fundamental concepts, which will significantly impact your ability to complete future courses.
Sharing, publishing, or distributing your assignment work is not permitted.
Do not provide or show yourWeChat: assignment work to any other person, other than the teaching staff of COMP1521. For example, do not message your work to friends.
Do not publish your assignmAssignment Project Exam Helpent code via the Internet. For example, do not place your assignment in a public GitHub repository.
Sharing, publishing, or distributing your assignment work after the completion of COMP1521 is not permitted. For example, do not place your assignment in a public GitHub repository after this offering of COMP1521 is over.
For all enquiries, please email the class account at [email protected]
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