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This article mainly explains "the internal architecture and working principle of Linux CPU". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let Xiaobian take you to learn "the internal architecture and working principle of Linux system CPU"!

CPU development history

On July 18, 1968, Bob North and Gordon Moore opened their new company at 365 Meadowfield Avenue in beautiful Manyview, California. Shortly after its founding, it paid $15000 to buy the rights to use the Intel name from a company called INTELCO. Intel, the semiconductor giant, thus began his legendary history in the IT industry.

November 15, 1971, is remembered as a landmark day in the global IT community and is written into many computer science textbooks. Intel engineer Ted Hoff invented the world's first microprocessor-4004, a 4-bit microprocessor that only had 45 instructions and could execute only 50,000 instructions per second. It is even inferior to ENIAC, the world's first computer developed by the U.S. Army University of Pennsylvania in 1946. However, its integration was much higher. The weight of a 4004 was less than a cup. He was named "one of the most influential scientists since World War II" by the British magazine The Economist for inventing the microprocessor. Intel's CPU development history is shown in the table below:

Pentium 1, Pentium 2, Pentium 3, Pentium 4, Pentium 4, Pentium 2, Pentium 3, Pentium 4, Pentium 1, Pentium 2, Pentium 3, Pentium 4, Pentium

Intel began with 8086 and entered what we call the x86 era. The birth of 80386 marks Intel's entry into the era of 32-bit microprocessors. CPU from 80386 to Pentium 4 is the legendary IA-32 era.

CPU working principle

We all know that the fundamental task of the CPU is to execute instructions, which for computers end up as a sequence of zeros and ones. CPU can be logically divided into three modules, namely control unit, arithmetic unit and memory unit, which are connected by CPU internal bus.

As follows:

Control unit: The control unit is the command and control center of the entire CPU, consisting of an instruction register IR(Instruction Register), an instruction decoder ID(Instruction Decoder) and an operation controller OC(Operation Controller), etc., which is extremely important for coordinating the orderly work of the entire computer. According to the program pre-programmed by the user, it successively fetches various instructions from the memory, places them in the instruction register IR, determines what operation should be performed by instruction decoding (analysis), and then sends micro-operation control signals to the corresponding parts according to the determined timing through the operation controller OC. Operation controller OC mainly includes pulse generator, control matrix, clock pulse generator, reset circuit and start-stop circuit control logic.

Unit: It is the core of the arithmetic unit. Arithmetic operations (including basic operations such as addition and subtraction multipliers and additional operations) and logical operations (including shifts, logical tests, or comparisons of two values) can be performed. In contrast to the control unit, the arithmetic unit receives commands from the control unit and performs operations, that is, all operations performed by the arithmetic unit are commanded by control signals sent by the control unit, so it is an execution component.

Storage unit: Including CPU on-chip cache and register group, it is the place where CPU temporarily stores data, which holds data waiting to be processed, or data that has been processed. The CPU accesses the register in a shorter time than accessing the memory. The use of registers can reduce the number of times the CPU accesses memory, thus increasing the CPU's working speed. However, due to the limitation of chip area and integration, the capacity of register bank cannot be very large. Register groups can be divided into special purpose registers and general purpose registers. The role of special registers is fixed, respectively register the corresponding data. General purpose registers are widely used and can be specified by programmers. The number of general purpose registers varies from microprocessor to microprocessor.

If you refine the above figure, you can conclude that the working principle of CPU is summarized as follows:

Generally speaking, the CPU fetches instructions and corresponding data from memory one by one, and performs arithmetic processing on the data according to the provisions of the instruction operation code until the program execution is completed.

summary

CPU operation principle: the control unit in the timing pulse under the action of the instruction counter pointed to the instruction address (this address is in memory) sent to the address bus, and then the CPU will read the instructions in this address to the instruction register for decoding. For the data needed to execute the instruction process, the data address will also be sent to the address bus, and then the CPU will read the data to the CPU's internal storage unit (that is, internal register) temporarily stored, and finally command the arithmetic unit to process the data. And so on and so forth until the power went out.

At this point, I believe that everyone has a deeper understanding of the "internal architecture and working principle of Linux system CPU". Let's actually operate it! Here is the website, more related content can enter the relevant channels for inquiry, pay attention to us, continue to learn!

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