24.4.1. Fetching and Decoding Instructions

Try these first

1. 1.

   What does the MPC do during instruction fetching?

   Hint

   Think about where the microinstructions are stored.

2. 2.

   What is the purpose of the Instruction Register (IR)?

   Hint

   What do we need to decode an instruction?

3. 3.

   What does MPC stand for?

   • Microprogram Control
   • Microprogrammed Control
   • Microprogrammed Processor

   Hint

   MPC is involved in memory fetching.

4. 4.

   True or False: The Op-Code is directly related to the operation being fetched.

   • True
   • False

   Hint

   Consider the function of Op-Code in instruction execution.

5. 5.

   Design a microprogram that incorporates branching for both addition and subtraction operations, illustrating how common sequences can be reused.

   Hint

   Think about what would be common before performing operations.

6. 6.

   Evaluate a scenario where the instruction register fetches an invalid instruction. Discuss how the control unit responds and what optimizations could prevent such situations.

   Hint

   Consider how common checks can ensure valid commands.