1.1.1 Structure & Function of the Processor Flashcards
What is the purpose of the Arithmetic Logic Unit?
Completes all the arithmetical and logical operations
What is the purpose of the Control Unit?
Directs operations inside the CPU
What are registers?
Small memory cells that operate at high speeds
What does the Program Counter store?
The address of the next instruction
What does the accumulator store?
Arithmetic & logic results of ALU
What does the Memory Address Register store?
The address of the location to be read from or written to
What does the Memory Data Register store?
The data read from or to be written to
What does the Current Instruction Register store?
The current instruction divided up into opcode & operand
What is a bus?
A set of parallel wires connecting two or more components together
What is the system bus?
The collection of the data bus, address bus & control bus
What is the width of a bus?
The number of parallel wires it has
What is the data bus?
A bidirectional bus used to transport data and instructions between components
What is the control bus?
A bidirectional bus used to transmit control signals between internal & external components
What is the address bus?
A unidirectional bus used to transmit the memory address specifying where data is to be sent to or retrieved from
What consequence does adding a wire to the address bus have?
Doubles the number of addressable locations
What does Bus Request indicate?
A request from a device for access to the data bus
What does Bus Grant indicate?
The CPU has granted access to the data bus
What does memory write do?
Causes the data on the data bus to be written into addressed location
What does memory read do?
Causes the data from the addressed location to be placed onto the data bus
What does the interrupt request control signal indicate?
A device is requesting access to the CPU
What is the clock control signal used for?
Synchronise instructions
What is assembly language?
Assembly language is a programming language where mnemonics are used to represent instructions
What is opcode?
Determines the type of instruction and what hardware is required to execute it
What is the operand?
Address of where the operation is performed
What occurs during the fetch phase of the FDE cycle?
The address from the PC is copied to the MAR
Instruction held at address copied to MDR by the data bus
Simultaenously the contents of the PC is increased by 1
The value of the MDR is copied to the CIR
What occurs during the decode phase?
The contents of the CIR is split into operand & opcode
What occurs during the execute phase?
The opcode is executed on the data
What is clock speed?
The number of clock cycles completed per second
What is cache memory?
A faster smaller segment of memory
Holds frequently used data/instructions
Built into processor so faster access
What is pipelining?
The process of completing stages of the FDE cycle simultaneously on numerous data/instructions
What is Von Neumann architecture?
CPU architecture with a single shared memory & shared data bus for both data & instructions
What is Harvard architecture?
CPU architecture with two separate memory & data buses for data & instructions
What is contemporary processing?
Von Neumann architecture is used for main memory
Harvard architecture is used for cache, dividing into instruction cache & data cache
