A DIGITAL COMPUTER HAS A MEMORY UNIT WITH 48 BITS PER WORD

Task

 

1. A digital computer has a memory unit with 48 bits per word. The instruction set consists of 240 different operations. All instructions have an operation code part (opcode) and an address part (allowing for only one address). Each instruction is stored in one word of memory.[4 marks]

 

1. How many bits are needed for the opcode?  
2. How many bits are needed to specify the register?
3. How many bits are left for the address part of the instruction?
4. What is the maximum allowable size for memory?
5. What is the largest unsigned binary number that can be accommodated in one word of memory?

 

2. Write a MARIE program using a loop that multiplies two non-negative numbers by using repeated addition. For example, to multiply 3 x 6, the program would add 3 six times (e.g. 3 + 3 + 3 + 3 + 3 + 3) or add 6 three times (e.g. 6+6+6). You should write and run the program using MARIE simulator. Also write the code with Address, Instruction, and Comments. [5 Marks]

 

 

 

3. Consider an instruction Add 1000. Memory contents, Accumulator (AC), and R1 Register contents are depicted in the below figure: (such as memory address 1000 contains a value 1400, memory address 1100 contains a value 400 etc. All the numbers used here are decimals). [6 marks]

 

Assuming R1 is implied in the indexed addressing mode, determine the actual value loaded into the accumulator (AC) using the following addressing modes:

 

1. Immediate
2. Direct

• Indirect

1. Indexed

 

Online submission via Turnitin is required for this assignment.

 

Rationale

 

This assessment task covers topics on CPU operation and Instruction Set Architecture, and has been designed to ensure that you are engaging with the subject content on a regular basis. More specifically it seeks to assess your ability to:

• be able to define and appropriately use computer systems terminologies;
• be able to describe the essential elements of computer organisation and discuss how the elements function;
• be able to describe the basic instruction set architecture of a simple computer;
• be able to discuss the general trends in computing technologies including examples of leading edge developments.

 

Marking Criteria

The following marking criteria will be used to mark this assignment:

 

Questions	Fail (	Pass (50% - 64%)	Credit (65% - 74%)	Distinction (75% - 84%)	High Distinction (>84%)
Question 1	Incorrect answer with no demonstration of understanding the topic.	Student demonstrate the understanding, however the calculations are incorrect.	Answers are correct, omission of few calculations.		Answers are correct and clearly show the calculations
Question 2	Incorrect answer with no demonstration of understanding the topic.	Student demonstrate the understanding, however the testing are incorrect.	Answers are correct, Not passed all tests.		Answers are correct and clearly show the calculations The program should be tested using different combination of inputs, such as 3 and 6, 5 and 9, 2 and 18 etc... Also check using any or both 0s, such as 3 and 0, 0 and 8, 0 and 0 etc.
Question 3	Answers are incorrect	Only two of them are correct	There is a mistake in answer		Answers are correct and clearly show the process steps