Assignment 1: Cat Scan in MIPS

version: 1.1 last updated: 2025-03-07 16:50:00

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 cat_scan, change to this directory, and fetch the provided code by running these commands: 

mkdir -m 700 cat_scan
cd cat_scan
1521 fetch cat_scan

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:

  • cat_scan.s: a stub MIPS assembly file to complete.
  • cat_scan.c: a reference implementation of cat scan in C.
  • cat_scan.simple.c: a copy of the reference implementation of cat scan, for you to simplify.
  • input.txt: example input file.
  • cat_scan.mk: a make(1) fragment for compiling cat_scan.c.

😺📦 Cat Scan: The Game 🧶😻

1521 mipsy cat_scan.s
===============================================================
                     Welcome to Cat Scan!
===============================================================
┌─────────┐  ┌─────────┐  ┌─────────┐
│  /\_/\  │  │  /\_/\  │  │  /\_/\  │
│ ( o.o ) │  │ ( ^_^ ) │  │ ( -.- ) │
│ /     \ │  │ /     \ │  │ /     \ │
└─────────┘  └─────────┘  └─────────┘
===============================================================

Enter a random seed (from 0 to 65535): 12
Enter a height (from 4 to 12): 4
Enter a width  (from 4 to 12): 4

===============================================================
There are 1 cats hidden in a 4-by-4 box. Your goal is to deduce
their locations by rolling balls of string in from the edges
and noticing where they exit the grid.

Balls of string interact with cats as follows:
- Absorbed:         when hitting a cat directly.
- Deflected 90 degrees:  when passing diagonally near a cat.
- Reflected:        when aimed between two cats one square apart.
- Reflected:        when deflected before entering the box.
- Straight-line:    otherwise (no interaction).

Starting Score: 100

Points/Costs:
- Correct guess   = +25 points
- Incorrect guess = -25 points
- Rolling a ball  = -12 points

Available Commands:
 h - Print this help message.
 p - Print the game.
 a - Toggle auto-print ON/OFF.
 g - Guess a cat location.
 r - Roll a ball of string.
 s - Print game stats.
 c - Cheat (reveal cat positions).
 d - Debug info.
 q - Quit the game.

===============================================================

Enter Command: g
(guessing cat location)
Enter a row edge number (from 1 to 4): 3
Enter a col edge number (from 5 to 8): 8
          ┌───┬───┬───┬───┐
          │   │   │   │   │
          └───┴───┴───┴───┘
          ┌───┬───┬───┬───┐
          │ 16│ 15│ 14│ 13│
┌───┐ ┌───┼───┼───┼───┼───┼───┐ ┌───┐
│   │ │ 1 │   │   │   │   │ 12│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 2 │   │   │   │   │ 11│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │   │^_^│ 10│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ 9 │ │   │
└───┘ └───┼───┼───┼───┼───┼───┘ └───┘
          │ 5 │ 6 │ 7 │ 8 │
          └───┴───┴───┴───┘
          ┌───┬───┬───┬───┐
          │   │   │   │   │
          └───┴───┴───┴───┘
Good Guess! [+25 points]
You found "Baron Chonk"
All cats found.
┌─────────┐
│  /\_/\  │
│ (*^_^*) │
│ /     \ │
└─────────┘
You win! Final Score: 125

Cat Scan is a variation of Black Box, a game where players shoot X-rays into a box to determine the locations of atoms hidden inside.

In cat_scan.c, cats are hidden in a box across a two-dimensional grid. The goal is to deduce their locations by rolling balls of string into the box and observing where they exit the grid.

The image below illustrates a game in which 4 cats are hiding in an 8-by-8 box. The edges of the box are numbered counterclockwise from 1 to 32.

Diagram of Cat Scan

Balls of string interact with cats as follows:

  • Absorbed: When colliding directly with a cat. The green arrow shows the path travelled by a ball of string rolled from edge 22. This ball collides directly with the cat at the [2][3], so it is absorbed. The edge is labelled with an A to record this result.
  • Deflected 90 degrees: When passing diagonally near a cat. The blue arrow shows the path travelled by a ball that enters from edge 21. This ball is deflected 90 degrees to the left by the cat at [2][3], then 90 degrees to the right by the cat at [5][5]. The ball continues rolling and is deflected twice more before exiting the box at edge 4. The edges 21 and 4 are labelled 4 and 21, respectively.
  • Reflected: When aimed between two cats one square apart. The path of the ball rolled from edge 2 is aimed between the two cats at [0][3] and [2][3] so it reflects. It exits the box from the same edge it entered, which is labelled with an R.
  • Reflected: When passing by a cat located on the edge. The path of the ball rolled from edge 28 passes cat [0][3], which is located at the edge of the box, so the ball reflects, exiting the box from the same edge that it entered from. Again, this edge is labelled with an R.
  • Straight Line Travel: Otherwise. The dark gold arrow shows the path travelled by a ball of string rolled from edge 8. It doesn't interact with any cats, so continues in a straight line and exits the box at edge 8. The edges 8 and 17 are labelled 17 and 8, respectively.

Note: absorption takes priority over deflection.

When playing the game, the player has two main commands:

  • g (guess) allows the player to guess the location of a cat.
  • r (roll) rolls a ball of string into the box from a given edge.
The game is won when the locations of all cats have been guessed. Guessing cat locations and rolling balls of string cost points. If the player does not have sufficient points for another guess, then the game is lost.

An example game of cat scan can be seen to the right.

To get a feel for this game, try it out in a terminal: 

dcc cat_scan.c -o cat_scan
./cat_scan

You should read through cat_scan.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 assignment.

cat_scan.s: The Assignment

Your task in this assignment is to implement cat_scan.s in MIPS assembly.

You have been provided with some assembly and some helpful information in cat_scan.s. Read through the provided code carefully, then add MIPS assembly so it executes exactly the same as cat_scan.c.

You have to implement the following functions in MIPS assembly:

  • main
  • print_welcome
  • game_setup
  • prompt_for_int
  • initialise_ball_of_string
  • initialise_ball_paths
  • initialise_box
  • print_stats
  • game_loop
  • is_cat_at_position
  • do_move_ball_forward
  • do_turn_ball
  • spawn_cats
  • guess_cat_location
  • handle_ball_movement
  • generate_cat_name
  • roll_ball_of_string

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 function which is called.

The following functions have already been translated to MIPS assembly for you:

  • random_in_range
  • update_random_number
  • process_command
  • print_help
  • print_debug_info
  • print_smiling_cat
  • print_crying_cat
  • configure_ball
  • check_ball_interactions
  • edge_number_from_position
  • print_game
  • print_game_row_upper
  • print_game_row_inner
  • print_game_row_lower
  • print_grid_row_edge
  • print_grid_row_edge_upper
  • print_grid_row_edge_inner
  • print_grid_row_edge_lower
  • print_grid_row_cells
  • print_cell_content
  • is_position_in_box
  • is_position_an_edge_number
  • is_position_a_path_result
  • print_edge_number

Subsets

This assignment is split into four subsets. Later subsets will involve more complex translation.

Subset Functions Performance Weight
Subset 0
  • main
  • print_welcome
 10%
Subset 1
  • game_setup
  • prompt_for_int
  • initialise_ball_of_string
  • initialise_ball_paths
  • initialise_box
  • print_stats
 45%
Subset 2
  • game_loop
  • is_cat_at_position
  • do_move_ball_forward
  • do_turn_ball
  • spawn_cats
 25%
Subset 3
  • guess_cat_location
  • handle_ball_movement
  • generate_cat_name
  • roll_ball_of_string
 20%

The performance mark for the final subset also includes tests which run the program as a whole.

Commands

The get_command function calls various other functions. When translating you should follow the exact behaviour of the C code, however when testing you may find it useful to consult the following table of commands.


Command Description Function called
h Print this help message print_help
p Print the game print_game
a Toggle auto-print ON/OFF
g Guess a cat location guess_cat_location
r Roll a ball of string into the box from an edge roll_ball_of_string
s Print game stats print_stats
c Cheat (shows cat locations) print_game
d Output debugging information print_debug_info
q Quit the game

Running & Testing

To run your MIPS code, simply enter the following in your terminal: 

1521 mipsy cat_scan.s

Manual Testing

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 cat_scan.c -o cat_scan
cat input.txt | ./cat_scan | tee c.out
cat input.txt | 1521 mipsy cat_scan.s | tee mips.out
diff -s c.out mips.out
Files c.out and mips.out are identical

Try this for different sequences of inputs. When testing some functions you may find using the d command (which calls print_debug_info) to be useful.

Automated Testing

There are two types of autotests for this assignment:

  1. Whole Program Tests
  2. Function Tests

Whole Program Tests run your entire cat_scan.s file and compare the observed output against the expected output. These tests are generally not practical until most or all of your functions have been implemented in MIPS.

Function Tests only test individual functions from cat_scan.s. These tests isolate a function and run it separately to the rest of your solution. For example, you can test the main function with: 

1521 autotest cat_scan main
The result of this test is based entirely on the implementation of the main function. It does not depend on the correctness of any other functions that main calls, such as print_welcome, game_setup, or game_loop.

Hints

  • You should implement all the functions from one subset before moving on to the next.

  • You may find the provided process_command and print_debug_info function implementations to be useful guidance for your implementation including comments, label names, indentation and register usage.

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 cat_scan.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: 

1521 autotest cat_scan.simple

An example game of Cat Scan

1521 mipsy cat_scan.s
===============================================================
                     Welcome to Cat Scan!
===============================================================
┌─────────┐  ┌─────────┐  ┌─────────┐  ┌─────────┐  ┌─────────┐
│  /\_/\  │  │  /\_/\  │  │  /\_/\  │  │  /\_/\  │  │  /\_/\  │
│ ( o.o ) │  │ ( ^_^ ) │  │ ( -.- ) │  │ ( uwu ) │  │ ( z_z ) │
│ /     \ │  │ /     \ │  │ /     \ │  │ /     \ │  │ /     \ │
└─────────┘  └─────────┘  └─────────┘  └─────────┘  └─────────┘
===============================================================

Enter a random seed (from 0 to 65535): 3778
Enter a height (from 4 to 12): 8
Enter a width  (from 4 to 12): 8

===============================================================
There are 4 cats hidden in a 8-by-8 box. Your goal is to deduce
their locations by rolling balls of string in from the edges
and noticing where they exit the grid.

Balls of string interact with cats as follows:
- Absorbed:         when hitting a cat directly.
- Deflected 90 degrees:  when passing diagonally near a cat.
- Reflected:        when aimed between two cats one square apart.
- Reflected:        when deflected before entering the box.
- Straight-line:    otherwise (no interaction).

Starting Score: 400

Points/Costs:
- Correct guess   = +25 points
- Incorrect guess = -25 points
- Rolling a ball  = -25 points

Available Commands:
 h - Print this help message.
 p - Print the game.
 a - Toggle auto-print ON/OFF.
 g - Guess a cat location.
 r - Roll a ball of string.
 s - Print game stats.
 c - Cheat (reveal cat positions).
 d - Debug info.
 q - Quit the game.

===============================================================

Enter Command: p
(printing game)
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │   │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│   │ │ 1 │   │   │   │   │   │   │   │   │ 24│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │   │   │   │   │   │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │   │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │   │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘

Enter Command: s
(printing game stats)
You have 400 points = 16 guesses / 16 roll(s) left, with 4 cat(s) remaining.

Enter Command: g
(guessing cat location)
Enter a row edge number (from 1 to 8): 4
Enter a col edge number (from 9 to 16): 13
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │   │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│   │ │ 1 │   │   │   │   │   │   │   │   │ 24│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │   │   │   │   │   │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │   │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Bad Guess [-25 points]
You have 375 points = 15 guesses / 15 roll(s) left, with 4 cat(s) remaining.

Enter Command: r
(rolling ball of string from edge)
Enter an edge number (from 1 to 32): 30
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│   │ │ 1 │   │   │   │   │   │   │   │   │ 24│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │   │   │   │   │   │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │   │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Ball entered 30 and was ABSORBED
Roll Cost [-25 points]
You have 350 points = 14 guesses / 14 roll(s) left, with 4 cat(s) remaining.

Enter Command: r
(rolling ball of string from edge)
Enter an edge number (from 1 to 32): 1
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │   │   │   │   │   │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │   │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Ball entered 1 and exited 24
Roll Cost [-25 points]
You have 325 points = 13 guesses / 13 roll(s) left, with 4 cat(s) remaining.

Enter Command: r
(rolling ball of string from edge)
Enter an edge number (from 1 to 32): 2
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │   │   │   │   │   │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │   │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Ball entered 2 and exited 31
Roll Cost [-25 points]
You have 300 points = 12 guesses / 12 roll(s) left, with 4 cat(s) remaining.

Enter Command: r
(rolling ball of string from edge)
Enter an edge number (from 1 to 32): 11
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │   │   │   │   │   │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Ball entered 11 and was ABSORBED
Roll Cost [-25 points]
You have 275 points = 11 guesses / 11 roll(s) left, with 4 cat(s) remaining.

Enter Command: g
(guessing cat location)
Enter a row edge number (from 1 to 8): 3
Enter a col edge number (from 9 to 16): 11
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │   │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Good Guess! [+25 points]
You found "Empress Nibbleton"
You have 300 points = 12 guesses / 12 roll(s) left, with 3 cat(s) remaining.

Enter Command: r
(rolling ball of string from edge)
Enter an edge number (from 1 to 32): 12
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │   │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │ 14│   │ 12│   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Ball entered 12 and exited 14
Roll Cost [-25 points]
You have 275 points = 11 guesses / 11 roll(s) left, with 3 cat(s) remaining.

Enter Command: g
(guessing cat location)
Enter a row edge number (from 1 to 8): 3
Enter a col edge number (from 9 to 16): 15
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │ X │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │ 14│   │ 12│   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Bad Guess [-25 points]
You have 250 points = 10 guesses / 10 roll(s) left, with 3 cat(s) remaining.

Enter Command: r
(rolling ball of string from edge)
Enter an edge number (from 1 to 32): 7
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │ X │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │ 14│   │ 12│   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Ball entered 7 and exited 7
Roll Cost [-25 points]
You have 225 points = 9 guesses / 9 roll(s) left, with 3 cat(s) remaining.

Enter Command: r
(rolling ball of string from edge)
Enter an edge number (from 1 to 32): 6
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │ X │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ A │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │ 14│   │ 12│   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Ball entered 6 and was ABSORBED
Roll Cost [-25 points]
You have 200 points = 8 guesses / 8 roll(s) left, with 3 cat(s) remaining.

Enter Command: r
(rolling ball of string from edge)
Enter an edge number (from 1 to 32): 5
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │ X │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ A │ │ 6 │   │   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │ 14│   │ 12│   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Ball entered 5 and exited 5
Roll Cost [-25 points]
You have 175 points = 7 guesses / 7 roll(s) left, with 3 cat(s) remaining.

Enter Command: g
(guessing cat location)
Enter a row edge number (from 1 to 8): 6
Enter a col edge number (from 9 to 16): 9
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │   │   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │ X │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ A │ │ 6 │^_^│   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │ 14│   │ 12│   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Good Guess! [+25 points]
You found "Count Crumpet"
You have 200 points = 8 guesses / 8 roll(s) left, with 2 cat(s) remaining.

Enter Command: r
(rolling ball of string from edge)
Enter an edge number (from 1 to 32): 28
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │ 13│   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │ X │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ A │ │ 6 │^_^│   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │ 14│ 28│ 12│   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Ball entered 28 and exited 13
Roll Cost [-25 points]
You have 175 points = 7 guesses / 7 roll(s) left, with 2 cat(s) remaining.

Enter Command: r
(rolling ball of string from edge)
Enter an edge number (from 1 to 32): 4
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │ 13│   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │ X │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 5 │   │   │   │   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ A │ │ 6 │^_^│   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │ 14│ 28│ 12│   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Ball entered 4 and exited 4
Roll Cost [-25 points]
You have 150 points = 6 guesses / 6 roll(s) left, with 2 cat(s) remaining.

Enter Command: g
(guessing cat location)
Enter a row edge number (from 1 to 8): 5
Enter a col edge number (from 9 to 16): 11
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │ 13│   │   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │ X │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 5 │   │   │^_^│   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ A │ │ 6 │^_^│   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │ 14│ 28│ 12│   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Good Guess! [+25 points]
You found "Empress Fluffernap"
You have 175 points = 7 guesses / 7 roll(s) left, with 1 cat(s) remaining.

Enter Command: r
(rolling ball of string from edge)
Enter an edge number (from 1 to 32): 21
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │ 13│   │   │ 21│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │ X │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │ 25│
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 5 │   │   │^_^│   │   │   │   │   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ A │ │ 6 │^_^│   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │ 14│ 28│ 12│   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Ball entered 21 and exited 25
Roll Cost [-25 points]
You have 150 points = 6 guesses / 6 roll(s) left, with 1 cat(s) remaining.

Enter Command: g
(guessing cat location)
Enter a row edge number (from 1 to 8): 5
Enter a col edge number (from 9 to 16): 15
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │ 2 │ A │   │ 13│   │   │ 21│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │ 32│ 31│ 30│ 29│ 28│ 27│ 26│ 25│
┌───┐ ┌───┼───┼───┼───┼───┼───┼───┼───┼───┼───┐ ┌───┐
│ 24│ │ 1 │   │   │   │   │   │   │   │   │ 24│ │ 1 │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ 31│ │ 2 │   │   │   │   │   │   │   │   │ 23│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 3 │   │   │^_^│   │   │   │ X │   │ 22│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 4 │   │   │   │   │ X │   │   │   │ 21│ │ 25│
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 5 │   │   │^_^│   │   │   │^_^│   │ 20│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ A │ │ 6 │^_^│   │   │   │   │   │   │   │ 19│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│ R │ │ 7 │   │   │   │   │   │   │   │   │ 18│ │   │
├───┤ ├───┼───┼───┼───┼───┼───┼───┼───┼───┼───┤ ├───┤
│   │ │ 8 │   │   │   │   │   │   │   │   │ 17│ │   │
└───┘ └───┼───┼───┼───┼───┼───┼───┼───┼───┼───┘ └───┘
          │ 9 │ 10│ 11│ 12│ 13│ 14│ 15│ 16│
          └───┴───┴───┴───┴───┴───┴───┴───┘
          ┌───┬───┬───┬───┬───┬───┬───┬───┐
          │   │   │ A │ 14│ 28│ 12│   │   │
          └───┴───┴───┴───┴───┴───┴───┴───┘
Good Guess! [+25 points]
You found "Master Crumpet"
All cats found.
┌─────────┐
│  /\_/\  │
│ (*^_^*) │
│ /     \ │
└─────────┘
You win! Final Score: 175

Assumptions, Clarifications, and Restrictions

  • Like all good programmers, you should make as few assumptions as possible.

  • Your submitted code must be hand-written MIPS assembly, which you yourself have written.
    You may not submit code in other languages.
    You may not submit compiled output.

  • You may not copy a solution from an online source. e.g. Github.

  • Your functions will be tested individually. They must exactly match the behaviour of the corresponding C function and they must follow MIPS calling conventions.

  • You may assume the input provided to cat_scan.s will be correctly formatted. For example, where a number is expected the input will not be a letter.

  • 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 are 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.

Change Log

Version 1.0
(2025-02-10 15:30:00)
  • Initial release
Version 1.1
(2025-03-07 16:50:00)
  • Added the walkthrough video link

Assessment

Testing

We have provided some automated tests to help you check the correctness of your translation. To run all the provided tests, execute the following command: 
1521 autotest cat_scan
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 main function, run the command: 
1521 autotest cat_scan main
You can also run all the autotests for a particular subset. For example, to run all the autotests for subset 1, run the command: 
1521 autotest cat_scan S1
To run the autotests which test your program as a whole, run the command: 
1521 autotest cat_scan whole_prog
Some tests are more complex than 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 cat_scan main_S0_0

Submission

When you are finished working on the assignment, you must submit your work by running give: 

give cs1521 ass1_cat_scan cat_scan.s

You must run give before Week 5 Friday 18:00:00 to obtain the marks for this assignment. Note that this is an individual exercise, the work you submit with give must be entirely your own.

You can run give multiple times.
Only your last submission will be marked.

If you are working at home, you may find it more convenient to upload your work via give's web interface.

You cannot obtain marks by emailing your code to tutors or lecturers.

You can check your latest submission on CSE servers with: 

1521 classrun check ass1_cat_scan

You can check the files you have submitted here.

Manual marking will be done by your tutor, who will mark for style and readability, as described in the Assessment section below. After your tutor has assessed your work, you can view your results here; The resulting mark will also be available via give's web interface.

Due Date

This assignment is due Week 5 Friday 18:00:00 (2025-03-21 18:00:00).

The UNSW standard late penalty for assessment is 5% per day for 5 days - this is implemented hourly for this assignment.

Your assignment mark will be reduced by 0.2% for each hour (or part thereof) late past the submission deadline.

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 late, it would be awarded 57.8%.

Beware - submissions 5 or more days late will receive zero marks. This again is the UNSW standard assessment policy.

Assessment Scheme

This assignment will contribute 15 marks to your final COMP1521 mark.

80% of the marks for assignment 1 will come from the performance of your code on a large series of tests.

20% of the marks for assignment 1 will come from hand marking. These marks will be awarded on the basis of clarity, commenting, elegance and style. In other words, you will be assessed on how easy it is for a human to read and understand your program.

An indicative assessment scheme for performance follows.
The lecturer may vary the assessment scheme after inspecting the assignment submissions, but it is likely to be broadly similar to the following:

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.
The lecturer may vary the assessment scheme after inspecting the assignment submissions, but it is likely to be broadly similar to the following:

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 style an attempt at style.

An indicative style rubric follows.
The lecturer may vary the assessment scheme after inspecting the assignment submissions, but it is likely to be broadly similar to the following:

  • 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 commenting throughout the code
    • Descriptive label names, indicating structure

Note that the following penalties apply to your total mark for plagiarism:

0 for
assignment 1		 knowingly providing your work to anyone
and it is subsequently submitted (by anyone).
0 FL for
COMP1521		 submitting any other person's work; this includes joint work.
academic
misconduct		 submitting another person's work without their consent;
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.

    This is an individual assignment. The work you submit must be entirely your own work: submission of work even partly written by any other person is not permitted.

    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 your 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 assignment code via the Internet. For example, do not place your assignment in a public GitHub repository.

    Rationale: by publishing or sharing your work, you are facilitating other students using your work. If other students find your assignment work and submit part or all of it as their own work, you may become involved in an academic integrity investigation.

  • 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.

    Rationale: COMP1521 may reuse assignment themes covering similar concepts and content. If students in future terms find your assignment work and submit part or all of it as their own work, you may become involved in an academic integrity investigation.

Violation of any of the above conditions may result in an academic integrity investigation, with possible penalties up to and including a mark of 0 in COMP1521, and exclusion from future studies at UNSW. For more information, read the UNSW Student Code, or contact the course account.