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What is CPU?
CPU (Central Processing Unit) - otherwise known as a processor, is the electronic circuitry within a computer/ mobile devices that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions.
What is CPU Core?
The Core of CPU means a physical central processing unit. Each CPU “core” is actually a separate central processing unit, which is the part of the CPU that actually does the work. For example, a dual-core chip may look like a single CPU chip, but it actually has two physical central processing units on the chip and Quad core CPU has 4 central processing unit which makes the processing speed faster.
How does CPU Core work?
The designs of processors are extremely complex and vary widely between companies and even models. Their architectures for every leading company are constantly being improved to pack in the most amount of performance in the least amount of space and energy consumption. But despite all the architectural differences, processors go through 4 main steps whenever they process instructions: Fetch, Decode, Execute, and Writeback.
In the Fetch operation, processor core retrieves instructions that are waiting for it, usually from some sort of memory which includes RAM. Now in modern processor cores, the instructions are usually already waiting for the core inside the processor cache. The processors in the devices have an area called the program counter which essentially acts as a bookmark, letting the processor know where the last instruction ended and the next one begins.
After the fetch operation completes taking the immediate instruction, it goes on to decode it. Instructions often involve multiple areas of the processor core such as arithmetic and the processor core needs to figure this out. Each part has something called an opcode which tells the processor core what should be done with the information that follows it. Once the processor core has figured this all out, the different areas of the core itself can get to work.
At the execute step, the processor knows what it needs to do, and actually goes ahead and does it. What exactly happens here varies greatly depending on which areas of the processor core are being used and what information is put in. As an example, the processor can do arithmetic inside the ALU(Arithmetic Logic Unit). This unit can connect to different inputs and outputs to crunch numbers and get the desired result. The circuitry inside the ALU does all the magic like complex calculation, execution etc.
The final step, called writeback, simply places the result of what’s been worked on back into memory. Where exactly the output goes depends on the needs of the running application, but it often stays in processor registers for quick access as the following instructions often use it. From there, it’ll get taken care of until parts of that output need to be processed once again, which can mean that it goes into the RAM.
The whole process is done in a moment of time which is called “Instruction Cycle”. These instruction cycles happen ridiculously fast, especially now that we have powerful processors with high frequencies.Remember the above-mentioned process is done only one Core of the CPU. Now if you have Quad Core CPU, then the process will do at 4 CPUs at a time!
This is a very simple description of what is CPU Core and how it works in reality, they are far more complex and do a lot more than we realize. The current trend is that processor manufacturers are trying to make their chips as efficient as possible, and that includes shrinking the transistors. The more CPU cores result in more faster processing output with sufficient amount of RAM.
Credits: Google, Wikipedia, other blogs.
Previous Tech Class Lessons
Chapter 1: Introduction to Smartphone Specifications
Chapter 3: All You Need To Know About Augmented Reality
Chapter 4: All You Need To Know About Charging Cycle
Chapter 5: All About Activity Tracker & Fitness Band
Chapter 6: Internet of Things & Mi Home
Chapter 7: Infrared Blaster
Chapter 8: CPU Architecture, CPU,GPU
Chapter 9: Megapixels and Photo Quality
Chapter 10: PDAF and its difference with CDAF
Chapter 11: All About Network Bands
Chapter 12: All About Rooting
Chapter 13: All about Kernel
Chapter 14: All you need to know about Wi-Fi!
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