Activity 1: Understanding Direct-Mapped Cache Organization

1. Open the CPU-OS Simulator. Create a new program and enter the following code instruction by instruction (click on the "Instructions" tab, then click "ADD NEW", and select "NEW INSTRUCTION" for each instruction).

This program writes the numbers from 0 to 63 into memory addresses 0 to 63.

MOV #0, R01  

STB R01, @R01  

CMP #63, R01  

JEQ 31  

ADD #1, R01  

JMP 6  

HLT

2. Run the program by clicking "RUN", and observe the contents of the data memory by selecting "SHOW PROGRAM DATA MEMORY".

Then click "SHOW CACHE" to open the cache memory window.

3. Cache Configuration

Configure the cache memory with the following parameters:

Block Size: 4

Cache Type: Direct Mapped

Cache Size: 16

Write Policy: Write-Back

4. Additional Instructions

Insert the following instructions after the instruction JMP 6:

LDB 0, R00  

LDB 2, R00  

LDB 4, R00  

LDB 6, R00  

LDB 8, R00  

5. Execute the LDB instructions one by one by double-clicking each line.

7. What causes the number of cache misses reported? (0.75 pt)