Structure and function of the processor

the physical components which make up a computer system

an area of very fast memory inside the CPU itself which temporarily stores small amounts of binary data all arithmetic, logical, or shift operations take place in registers

central processing unit has a number of different components which enable it to carry out its task of executing instructions

the main system board which connects all the hardware components

• temporary storage/memory location • inside the CPU • used for a single specific purpose • faster access speed than RAM/secondary storage

direct the operations 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

completes all of the arithmetical and logical operations. A: all mathematical operations such as addition and subtraction on fixed or floating point numbers L: boolean logic operations such as AND, OR, NOT, and XOR also, shift operations on bits

holds the address of the next instruction to be executed

temporary storage for data being processed during calculations/stores the result • for I/O in processor, it acts as a buffer (holds data that is on its way to somewhere else)/gateway

holds the address of a location that is to be read from or written to

temporarily stores data that has been read or data that needs to be written • acts as a buffer (memory designed to hold data that is on its way to somewhere else)

holds the current instruction being executed, divided up into operand and opcode

the number of parallel wires the bus has. the width of the bus is directly proportional to the number of bits that can be transferred simultaneously at any given time buses are typically 8, 16, 32 or 64 wires wide

a set of parallel wires which connect two or more components inside the CPU - data bus - address bus - control bus ^collectively called system bus

a bi-directional bus used for transporting data and instructions between components

a bi-directional bus used to transmit control signals between internal and external components. its purpose is to transmit command, timing and specific status information between system components

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

determine the direction of data flow, and when each device can access the bus

uses mnemonics to represent instructions - a simplified way of representing machine code. the instruction is divided into operand and opcode in the CIR

specifies the type of instruction to be executed

contains the data or the address of the data upon which the operation is to be performed.

the sequence of operations that are completed to execute an instruction

• The address of the next instruction is copied from the PC to the MAR • instruction held at that address is copied to MDR by the data bus • simultaneously, the contents of the PC is incremented • the value held in the MDR is copied to the CIR

the contents of the CIR are split into operand and opcode opcode is used to determine the type of instruction and what hardware to use to execute it operand holds either: - actual data to be operated on - address of data to be used within the operation