The central processing unit or the CPU is a piece of hardware inside your computer that carries out all the necessary instructions inside your computer.
It can easily be considered the brain of your whole computer. Every single piece of instruction has to go through the CPU before being executed.
The operations performed by the CPU include basic arithmetic, logical and input-output operations. The thing which makes it even more important for any computer system is the speed at which it carries out all these functions.
To function at high speeds, the CPU uses certain storage places to store necessary and temporary information. This information is extracted at the time of need instantly when triggered. This brings us to our question, where does the CPU store its computations?
To answer that question, we will have to dig deep into how the CPU works but, to put it simply, the CPU stores its computations inside tiny pieces of memory called registers.
What are Computations?
The CPU is a very complex piece of hardware. All of the operations being carried out include long strands of millions of instructions from the CPU.
Computations are simply just mathematical operations. The part of the CPU that is responsible for carrying out such operations is called the Arithmetic Logic Unit or the ALU.
Mathematical operations can be as simple as adding two numbers or estimating the number of odd numbers between 1 and 5000. All of this is done in the blink of an eye thanks to memory.
Where Does The CPU Store Its Computations
Since the system’s memory (RAM) is outside the CPU and it takes time to access the data inside the RAM. So, to be able to carry out complex operations in the blink of an eye the CPU needs to store the relevant data close to itself or even better, inside it.
This is where the registers come into play. The CPU stores all its computations inside registers. They are tiny pieces of memory that are an integral part of the processor and can be accessed far more quickly than the RAM or the CPU’s cache (this is also a type of memory that is present inside the CPU).
Registers come with the CPU’s architecture meaning you cannot add or remove any registers from a processor’s chip by any means.
They come in different sizes which are determined by how much data they can hold according to their processors. The most common sizes are 8,16,32 and 64.
So, the order of saving memory goes like this. Firstly, being the fastest of them all, computations are stored in the registers followed by the cache and then the RAM respectively.
Why the Registers Instead of the CPU Cache?
Both the cache and registers are present inside the CPU but the registers are preferred over the cache while dealing with such quick operations.
You may be familiar with the term “memory hierarchy” which basically is the pyramid for different types of memories in the computer according to their sizes and speeds.
Well, bigger memories such as the hard drives are present at the bottom of the pyramid. They are the biggest available memories to the CPU but are the slowest.
The registers are present at the top of the pyramid which means that they are the fastest of the memories but are the smallest of them all. The CPU cache lies below the registers.
This means that although being present inside the CPU, the cache lag behind the registers in terms of speed.
How Do Registers Function?
Registers are tiny memory storages that are present inside the CPU. They are the fastest of all memory types, however, they are the smallest of them all as well.
They are almost similar to the cache and the RAM in building and function but they are specifically used by the CPU to store all its computations.
The way the CPU utilizes the registers to be as fast as possible is that while making any computation, it takes smaller chunks of necessary data from the system’s memory and transfers it to the registers where it is temporarily stored.
When the CPU is done with the operation, it sometimes transfers the instructions back to the system’s memory in order to make more room for future computations. And the cycle goes on.
Types of Registers
Different registers perform different tasks. Some are responsible for just storing information, for example, the data registers which are responsible for holding numeric data, whereas, others are responsible for finding the location of the data needed for a specific operation, for example, the index registers.
There are a ton of different registers each having its own functions according to the task you are performing on the computer and each of them holds its own crucial value.
To put it shortly, there are a lot of complex processes going on inside the CPU and it is true that the way I portrayed it, is not everything.
But my main goal while going with this was to put it as simply as possible for the readers to grasp and understand what actually is going on inside their computers.
I hope this article was helpful in that regard and after reading the article I am sure that you will now have the answer to anyone who asks you the question “Where does the CPU store its computations”.
Where does the computer store its data permanently?
The permanent storage available to the computer to store its data is called the HDD (Hard Disk Drive).
How is data stored in computer memory?
Computers store data in the form of electronic signals inside the memory. It stores data in the form of bytes which is a unit of memory. Bytes are made up of individual bits which are represented by using electric voltage, they can either be on or 1 or off or 0 at any particular time. The combination of bits inside a byte forms all the data.