Von Neumann Architecture

Von Neumann Architecture

1. Arithmetic Logic Unit (ALU)

   • The ALU performs all the calculations for the CPU
   • E.g it will perform simple addition and subtraction , binary shifts and logic operations (AND/OR/NOT)

2. Control Unit

   • It controls the flow of data between the CPU and other parts of the computer system
   • E.g it sends control signals to the memory. ALU and input/output devices

3. Registers

   • Program Counter
     • Stores the address of the next instruction to be run
   • Accumulator
     • Stores the intermediate results of a calculation
   • Current instruction register
     • Stores the instruction currently being used
   • Memory Address Register (MAR)
     • Stores the memory address where the data or instruction will be fetched/written
   • Memory Data Register (MDR)
     • Stores the data or instruction which is being fetched/written from/to memory

4. Cache

   • Stores frequently used instructions for the CPU
   • There are 3 different levels of cache.
     • A directory store, a data section and status information