1.1.1 Structure and Function of the processor

• What is the role of the processor in a computer?

  It executes instructions for programs
• What does the Arithmetic and Logic Unit (ALU) do?

  It completes arithmetical and logical operations
• What types of operations does the ALU perform?

  Arithmetical and logical operations
• What is the function of the Control Unit?

  It directs operations of the CPU
• What are the jobs of the Control Unit?

  • Control and coordinate CPU activities
  • Manage data flow between CPU and devices
  • Accept the next instruction
  • Decode instructions
  • Store resulting data back in memory
• What are registers in a CPU?

  Small memory cells operating at high speed
• What operations occur in registers?

  Arithmetic, logical, and shift operations
• What is the purpose of the Program Counter (PC)?

  • Holds the address of the next instruction to execute
• What does the Accumulator (ACC) do?

  • Stores results from calculations
• What is the function of the Memory Address Register (MAR)?

  • Holds the address of a location to read/write
• What does the Memory Data Register (MDR) temporarily store?

  • Data that has been read or needs to be written
• What is the role of the Current Instruction Register (CIR)?

  • Holds the current instruction being executed
• What are buses in a CPU?

  Parallel wires connecting CPU components
• What are the three types of buses in a CPU?

  • Data bus
  • Control bus
  • Address bus
• What does the width of a bus indicate?

  Number of parallel wires it has
• How does bus width affect data transfer?

  It is proportional to bits transferred simultaneously
• What is the function of the Data Bus?

  Transport data and instructions between components
• What is the purpose of the Address Bus?

  Transmit memory addresses for data retrieval
• What does the Control Bus do?

  Transmits control signals between components
• What are some control signals transmitted by the Control Bus?

  • Bus request
  • Bus grant
  • Memory write
  • Memory read
  • Interrupt request
  • Clock
• What does assembly code use to represent instructions?

  Mnemonics to simplify machine code
• How is an instruction divided in the Current Instruction Register?

  Into operand and opcode
• What is pipelining in CPU processing?

  • Completing fetch, decode, execute cycles simultaneously
  • Holds data in a buffer near the CPU
• What are the two types of pipelining?

  Instruction pipelining and arithmetic pipelining
• What is the fetch-decode-execute cycle?

  • Sequence of operations to execute an instruction
• What happens during the fetch phase?

  • Address from PC copied to MAR
  • Instruction copied to MDR by data bus
  • PC contents increased by 1
  • MDR value copied to CIR
• What occurs during the decode phase?

  • Contents of CIR split into operand and opcode
• What happens during the execute phase?

  • The decoded instruction is executed
• What are the factors affecting CPU performance?

  • Clock speed
  • Number of cores
  • Amount and type of cache memory
• What determines the clock speed of a CPU?

  The system clock generates switching signals
• What is a core in a CPU?

  An independent processor running its own cycle
• How does having multiple cores affect CPU performance?

  It allows multiple fetch-execute cycles simultaneously
• What is cache memory?

  • CPU's onboard memory
  • Stores instructions fetched from main memory
  • Allows quicker access to frequently used instructions
• What are the types of cache memory?

  • Level 1 Cache: Very fast, small capacity (2-64KB)
  • Level 2 Cache: Relatively fast, medium capacity (256KB-2MB)
  • Level 3 Cache: Much larger, slower memory cell
• What is Von Neumann Architecture?

  • Basic components of computer and processor
  • Shared memory and data bus for data and instructions
  • Built on the stored program concept
• What is Harvard Architecture?

  • Physically separate memories for instructions and data
  • Useful for embedded processors
  • Allows optimization of memory characteristics
• What are the advantages of Von Neumann Architecture?

  • Cheaper to develop
  • Easier control unit design
• What are the advantages of Harvard Architecture?

  • Quicker execution of instructions
  • Optimized memory sizes
• How do contemporary processors utilize both architectures?

  • Use Von Neumann for main memory
  • Use Harvard for cache division