13.4.1. Summary of Instruction Execution Phases

Try these first

1. 1.

   What does the Program Counter (PC) do?

   Hint

   Think about how the CPU knows which instruction to execute next.

2. 2.

   What is stored in the Instruction Register (IR)?

   Hint

   What part of the execution process involves looking at the instruction?

3. 3.

   What is the purpose of the Program Counter (PC)?

   • To execute an instruction
   • To store data
   • To track the address of the next instruction

   Hint

   Think about how the CPU processes instructions sequentially.

4. 4.

   True or False: The Memory Data Register (MDR) holds current instructions being executed.

   • True
   • False

   Hint

   Consider the role of memorized instructions versus data.

5. 5.

   If the Program Counter has a value of 5, what would it become after executing a fetch instruction? Explain the result.

   Hint

   Consider how PC increments after each instruction cycle.

6. 6.

   Illustrate how an 'ADD' instruction operates without accessing memory compared to a 'LOAD' instruction, emphasizing the role of registers.

   Hint

   Focus on where each source of information comes from.