1.1.1 Architecture of the CPU

• One purpose of the memory data register is to…

  Hold data fetched from or to be written to the memory.
• Control Unit

  Decodes instructions

  Sends signals to control how data moves around the CPU
• Accumulator

  A register

  Holds the result of calculations

  Used to hold data currently being processed by the central processor
• ALU

  Arithmetic Logic Unit

  The part of the CPU where data is processed and manipulated

  Performs calculations

  Handles logical comparisons allowing a program to make decisions

  Handles bit shifting
• Cache

  Memory inside the processor providing fast access to frequently used instructions and data
• CPU

  Central Processing Unit

  Decodes and executes instructions
• Fetch-Execute Cycle

  The complete process of retrieving an instruction from store, decoding it and carrying it out
• Memory Address Register (MAR)


  Small memory location inside the CPU to assist with the fetch-execute cycle

  Holds the address of the memory location currently being accessed