Paper 1 : CPU Flashcards
What does CPU stand for?
Central Processing Unit
What does the CPU do (simply)?
The CPU is the brain of the computer and processes all the data and instructions that make the computer work.
What are the two types of system architecture?
Von Neumann and Harvard.
What are the three main parts of the CPU?
The Control Unit (CU), The Arithmetic Logic Unit (ALU) and The Cache.
What are the 4 registers you’ll need to know?
Program counter, Memory address register (MAR), Memory Data Register (MDR) and the Accumulator.
What does the Control Unit Do?
It executes program instructions and is in overall control of the CPU. It controls the flow of data inside and outside the processor.
What does the ALU do?
Does the calculations on the computer. Also controls logic gates and the accumulator.
What does the Memory Address Register do?
Stores any memory address about to be used by the CPU. This address may store DATA or a CPU instruction.
What does the Memory Data Register do?
Holds the actual data or instruction. This might’ve come from the RAM or is going to the RAM
What does the Program counter do?
Holds the memory address of the current instruction.
What does the accumulator do?
Stores the immediate result of calculations in the ALU.
What happens in the fetch part of the Fetch Decode Execute Cycle?
First the memory address is copied to the MAR from the program counter. Next the instruction in the MAR address is copied to the MDR. After that, the program counter is increased to point to the memory address of the next instruction.
What happens in the decode and execute part of the Fetch Decode Execute Cycle?
The instruction is decoded, and then given to the CU. Then the instruction is carried out and the cycle repeats.
What is clock speed and what is it measured in?
Clock speed is the amount of instructions that can be completed in a second, it is measured in Hz (Hertz)
The higher the clock speed, the higher the ________
The higher the clock speed, the higher the performance.
