Assignment 6

General

The questions for this assignment are below. Record your answers in this response document. Do not copy the questions into your response document; only fill in your answers. When you are ready to turn it in, save it to your computer as a PDF with File→Download→PDF Document. Then submit that PDF to Canvas by the due date.

Little Computer

1. This Little Computer program takes one number as input and then prints either 0 or 1. Use a combination of reading the code and experimentation to find all the inputs that will cause it to print 1.

   You can use this Little Computer with the program already loaded.

   Address	Value
   00	901
   01	313
   02	215
   03	810
   04	514
   05	213
   06	810
   07	517
   08	902
   09	612
   10	516
   11	902
   12	000
   13	000
   14	005
   15	010
   16	000
   17	001

2. Translate this Little Computer Assembly to machine code.

   Address	Value	Assembly
   00	???	START INP
   01	???	STA X
   02	???	SUB SECRET
   03	???	BRP EXIT
   04	???	BRA START
   05	???	EXIT LDA SECRET
   06	???	OUT
   07	???	HLT
   08	???	X DAT 0
   09	???	SECRET DAT 10

Compression

3. The image below is a 6×6 area of a fax we are sending. Representing white squares with 1 and black squares with 0, we would represent the second row as 000000 and third row as 110011. The rows are sent one after another, so those rows together would be 000000110011. The whole image would look like a sequence of 36 bits.

   Give a run-length-encoded version of the whole image. Put counts in parentheses for clarity, e.g. (5)1 to indicate the digit one repeated five times.

   

4. Expand the following compressed string according to the same-as-earlier trick.
   QRSTUV-b3c6

5. Construct a Huffman code given these symbols and their relative weights.

   Symbol	Weight
   A	4
   B	3
   C	2
   D	10
   E	4

   Show your final Huffman tree with all of the symbols at the leaves, and a table showing what code is used for each symbol. Constructing the tree is likely to be easiest on paper; just put a readable picture of your work in your response document.

6. What kind of tricks can we use while compressing data like images that we could not use if we were compressing a spreadsheet containing student grades?

Impacts of Computing: Sending messages

7. Use the framework laid out in the Impacts of Computing material in Welcome to CS to analyze and respond to the following article.

   Oklahoma City Police Department to implement Clearview AI technology