Von Neuman Architecture Flashcards
What is the Arithmetic and Logic Unit?
It carries out all the arithmetical and logical operations of the CPU. E.g. +, -, / , x, boolean operations (AND, OR, NOT) and comparing numbers (which one is bigger).
What is the Control Unit?
It organises the fetch-execute cycle
It also controls the flow of data in the CPU
What are registers?
Used to hold information needed by the CPU. Each register holds a specific piece of information.
What are the different types of registers?
- Accumulator (ACC) - Holds the calculations performed by the ALU.
- Program Counter (PC) - holds the address of the next instruction that is needed by the CPU to be fetched. Every time the execute phase is run, the pc is incremented by 1.
Memory Address Register (MAR) -holds the address of the current instruction that is to be fetched from memory, or the address in memory to which data is to be transferred.
Memory Data Register (MDR) - stores the data that are being read or written to. Once the data has been received it is stored. Stores the data returned from the address.
Current Instruction Register (CIR)- contains the instructions currently being carried out.
What is the fetch-decode-execute cycle?
Fetch - The address of the instruction that needs to be processed next is copied from the Program Counter (PC) to the Memory Address Register (MAR).
The PC is incremented to point to the next instruction that will be needed when the cycle starts again.
The instruction stored at the location held by the MAR is copied to the MDR.
Decode - The Control Unit decodes the instruction and sends control signals to the component within or outside the CPU that needs to act.
Execute - The operation indicated by the instruction is performed by the appropriate component.
What is parallel processing?
When multiple processes are carried out simultaneously
