CPU Flashcards
What are Registers Used for?
store data, instructions or addresses on the actual processor.
What are the two types of registers?
MAR, MDR
What Does the MAR do?
Holds the address of the next item of data that is needed by the processor
What Does MDR do?
Holds data to be passed to the data bus or Received from the data bus
What are the two types of Buses
Address Bus, Data Bus
What is an Address bus
a Uni-directional Bus which passes addresses from the CPU to Ram
What is a Data Bus
A Multi-directional Bus which carries Data to or from the CPU
What is a Control Unit/Bus
A collection of lines which signals the current state of the processor and fetch execute cycle.
What types of Control Unit lines are there
Byte Enable Line, Read Line, Write Line, Clock Line, Interrupt Line, Reset Line
What Does the Byte Enable Line do
specifies the instruction size of the data being sent/received
What Does the Read Line do
initiates a memory read operation
What Does the Write line do
Initiates a memory write operation
What Does the Clock do
States the pace of the fetch/execute cycle
What Does the Interrupt Line do
Used to indicate that an interrupt to the fetch/execute cycle is taking place
What Does the Reset Line do
Resets the processor to the Base state
What is an ALU used for
to carry out operations that require the use of:
Arithmetic operations
Logical operations
What is Clock speed
Clock speed is the rate at which a processor can complete a processing cycle
What is Clock Speed measured in
Gigahertz - GHz
What is a multicore Processor
A single processor which has two or more separate processing Units called cores
Name for Two cores
Dual Core
Name for Four cores
Quad Core
Name for Eight cores
Octa Core
Advantages of Multiple Cores
More instructions which can be processed at once
What is the width of a data bus referred to as
Word Size
What does increasing word size do
Increases System Performance
Steps for Fetch Execute Cycle for Memory Read
- The processor sets up the address bus with the required address.
- The processor activates the read line on the control bus
- An instruction is fetched from the memory location using the data bus and stored in the instruction register.
4.The instruction in the instruction register is then interpreted by the decoder and carried out.
Steps for Fetch Execute Cycle for Memory Write
- The processor sets up the address bus with the required address.
2.The processor sets up the data bus with the required data to be written
3.The control unit write line is activated
4.Data bus transfers the data to the memory location specified on the address bus
Explain why increasing the width of the data bus will improve the system performance
More bits can be fetched in a single operation
