Function and structure of the Processor Flashcards
Arithmetic and Logic Unit
Component of the processor, which is responsible for all arithmetical and logical operations.
What are Arithmetic operations?
All mathematical operations such as addition and subtraction on fixed or floating point numbers.
Control Unit
Component of the processor which directs the operations of the CPU.
What does CU stand for?
Control Unit
What are the roles of the CPU?
- Controlling and coordinating the activities of the CPU
- Managing the flow of data between the CPU and other devices
- Accepting the next instruction
- Decoding instructions
- Storing the resulting data back in memory
Registers
Small memory cells that operate at a very high speed.
What is a register?
Small memory cells that operate at a very high speed.
What is the purpose of a register?
Temporarily store data and all arithmetic, logical and shift operations occur in these register.
What are the 5 types of registers?
Program counter Accumulator Memory data register Memory address register Current instruction register
What does PC stand for?
Program counter
What is a program counter?
The program counter holds the address of the next instruction to be executed.
What does ACC stand for?
Accumulator
What is an Accumulator?
Stores the results of the ALU
What is a Logical operations?
Boolean logic operations such as AND, OR, NOT, XOR. NAND and NOR.
Memory data register
Temporarily stores data that has been read
or data that needs to be written
Memory address register
Holds the address of a location that is to be read from or written to.
What does MDR stand for?
Memory data register
What does MAR stand for?
Memory address register
What does CIR stand for?
Current instruction register
Current instruction register
Holds the current instruction being executed, divided up into operand and opcode.
What is a bus?
A set of parallel wires, which connect 2 or more components inside the CPU. There are three buses in the CPU: data bus, control bus, and address bus. These buses collectively are called the system bus.
What is a data bus?
Bi-directional bus (meaning bits can be carried in both directions). This is used for transporting data and instructions between components.
What is an address bus?
This is the bus used to transmit the memory addresses specifying where data is to be sent to or retrieved from. The width of the address bus is proportional to the number of addressable memory locations.
The control signals include
The control signals include:
- Bus request: shows that a device is requesting the use of the data bus
- Bus grant: shows that the CPU has granted access to the data bus
- Memory write: data is written into the addressed location using this bus
- Memory read: data is read from a specific location to be placed onto the data bus,
- Interrupt request: shows that a device is requesting access to the CPU
- Clock: used to synchronize operations
