Processor Components Flashcards
ALU
ALU = Arithmetic Logic Unit
Overview of a Processor
ALU
CU
MU
CU
CU=Control Unit
MU
MU= Memory Unit
Define Control Unit
The part of the processor that runs the machine code.
Has the responsibility of coordinating the rest of the processor.
The exact nature of the CU is dependent on the architecture of the CPU.
Define ALU
Responsible for performing calculations and logic.
E.g. simple arithmetic or comparisons.
Also acts as a gateway to the processor – all inputs and outputs to and from the processor have to pass through the ALU.
Memory Unit
Responsible for accessing memory.
The MU will store currently running programs, current files and the operating system.
Register
A register is a small block of memory, normally about 4/8 bytes, which is used in order for instructions to be processed.
(Machine instructions can only work if they are loaded into registers)
(Programs tend to load and save data into general purpose registers. These can be used for any purpose the programmer )
Different registers
PC MAR MDR CIR ACC
PC
Program Counter
A special purpose register which stores the address of the next instruction to be carry out.
MAR
Memory address register
A special purpose register which stores the address of the next instruction or data to be fetched into the CPU.
This is where the address that was read by the PC is sent.
ROM
ROM ,that the data that is stored on it can not be altered or deleted.
This is useful because the data always stays in the ROM even when the computer is powered off.
To store computers’ BOIS
2 Memory
Read Only Memory (ROM)
Random Access Memory (RAM)
RAM
RAM is categorised by the fact that it is wiped clear when the computer is powered off,this enables the computer to do more than one thing.
Define MDR
Memory data register
A special purpose register which stores the data fetched using the address found in the MAR.
