1.1 Characteristics of Contemporary Processors

What is the function of the arithmetic logic unit (ALU)?

Performs arithmetic calculations such as addition and subtraction on floating point numbers and boolean logic

What is the function of the Control Unit (CU)?

Controls and coordinates the activities in the CPU

Decoding instructions

Uses control signals to enable data to be read and written to and from main memory

Name the CPU's registers and their function

Program counter (PC) - holds the address of the next instruction to be executed

Accumulator (ACC) - stores the results of the ALU

Memory address register (MAR) - temporarily holds the address of the instruction being read or written

Memory data register (MDR) - temporarily holds the data being read or written

Current instruction register (CIR) - holds the current instruction being executed

What are the 3 buses in the CPU?

Address bus - transmits the memory address of an instruction

Data bus - transports data to and from components

Control bus - transmits control signals to internal and external components

Describe the fetch stage of the FDE cycle

PC copies address of next instruction to MAR

Instruction held at the address is copied to the MDR by the data bus

PC is incremented by 1

The contents of the MDR is copied to the CIR

Describe the decode stage of the FDE cycle

The contents of the CIR and split into operand and opcode

How does clock speed affect CPU performance?

The higher the clock speed, the greater the number of instructions that can be carried out per second

What are the factors affecting CPU performance

Clock speed

Number of cores

Cache size

How does the number of cores affect CPU performance?

The more cores, the more FDE cycles can occur per second

What is cache memory?

Stores the most frequently used instructions and data

What is pipelining?

The process of completing the fetch, decode and execute of three separate files simultaneously.

Describe the Von Neumann architecture