Fetch-decode-execute cycle

• What is the fetch-decode-execute cycle?

  It is a continuous process by the processor.
• How does the control unit ensure instructions are executed correctly?

  By fetching instructions from memory in order
• How does the control unit coordinate data flow?

  By managing interactions between ALU, registers, and memory
• What does the control unit decode?

  Instructions to understand what they do
• What is the first step in the fetch-decode-execute cycle?

  Fetch phase
• What do Operands specify?

  The data or registers involved
• What is the purpose of the Decode phase?

  To analyze the instruction in the Instruction Register
• When might memory be accessed during the Execute phase?

  To read or write data
• How does the processor run programs?

  By repeating the fetch-decode-execute cycle.
• Why is the control unit important for program execution?

  It ensures programs run smoothly by managing the cycle
• What are the main steps in the Execute phase of the instruction cycle?

  1. Control Unit activates processor parts
  2. ALU performs calculations using registers
  3. Registers store intermediate results
  4. Memory may be accessed to read/write data
  5. Program counter increments for next instruction
• What are the steps of the fetch-decode-execute cycle?

  1. Fetch: Gets instructions from memory
  2. Decode: Understands the instruction
  3. Execute: Carries out the instruction
• What are the key functions of the control unit?

  • Fetching instructions from memory
  • Decoding instructions to understand their purpose
  • Coordinating data flow between ALU, registers, and memory
  • Controlling processor operations at each step
• What happens to the program counter (PC) after execution?

  It increments to fetch the next instruction
• What does the control unit analyze during the Decode phase?

  The instruction in the Instruction Register
• What does the Program Counter (PC) hold?

  Memory address of the next instruction
• What is the role of the control unit in a processor?

  It manages the fetch-decode-execute cycle
• What does the OpCode indicate?

  The type of operation
• What are the main components involved in the Fetch phase?

  • Program Counter (PC): Holds next instruction address
  • Memory Access: Control unit reads instruction from RAM
  • Instruction Register (IR): Stores fetched instruction for decoding
• What is the final step in the instruction cycle?

  Execute phase
• What happens to the instruction after it is fetched?

  It moves to the decode phase
• What do registers store during execution?

  Intermediate results
• Which unit does the control unit signal for calculations?

  Arithmetic Logic Unit (ALU)
• How does the control unit respond after analyzing the instruction?

  It determines which parts of the processor to activate
• What role does the ALU play in the Execute phase?

  Performs calculations using data from registers
• What is the relationship between the Decode phase and the control unit's function?

  The Decode phase informs the control unit's actions
• What does the control unit do in the Execute phase?

  Activates parts of the processor for instructions
• What is stored in the Instruction Register (IR)?

  The fetched instruction for decoding
• What are the key components analyzed in the Decode phase?

  • OpCode: Type of operation
  • Operands: Data or registers involved
• What does the control unit do during memory access in the fetch phase?

  Reads the instruction from RAM