The CPU Flashcards
What does a CPU do?
It acts as the brain of the computer system, it processes all the data and instructions that make the system workl
How is the speed and power of a CPU determined?
It depends on the clock speed, amount of cores and cache size
What types of structure of CPU are the most common?
Von Neumann and Harvard architechtures
What are the three main parts of a CPU?
The control unit (CU), arithmetic logic unit (ALU), and the cache
What is the Control Unit?
It has overall control of the CPU. It starts program instructions by following the fetch-decode-execute cycle. It controls data flow inside and outside CPU
What is the ALU?
It completes all the calculations. Can do addition, subtraction, compare size or numbers. Contains an accumulator part. Performs basic logic operations such as AND, OR and NOT
What is the cache?
It is very fast memory, faster than RAM but slower than the registers (MDR and MAR). Stores regularly used commands by the CPU. They are expensive and have a low capacity. Different levels level 1 is the fastest bu lowest capacity and level 3 is the largest but alos the slowest
What is in Von Neumans CPU architecture?
Program counter, accumulator, memory adress register, memory data register
What does the program counter (PC) do?
Holds the memory address of the instruction for each cycle (counts the stage of each line)
What does the accumulator do?
Stores intermidiate results of calculations in the ALU
What does the memory adress register do?
Holds any memory adress about to be used by the CPU, could point to a price of data or an CPU instruction
What does the memory data register do?
Holds actual data or instruction. Data Could have been taken in by the RAM or other memory sources
What cycle do CPUs follow?
The Fetch-Decode-Execute cycle
What is the fetch part of the cycle?
Copy the memory adress from the program counter to the MAR, then the instruction gets copied to the MDR, the program counter increments to point to the memory adress of the next instruction ready for the next cycle
What happens in the decode part of the cycle?
The instruction in the MDR is decoded by the CU, then th CU prepares for the next step and loads the values into the MAR or MDR
