Devices included in the processor: a description, functions

Today, in the homes of the vast majority of residents of developed countries, there are several computers, as well as tablets and other mobile devices. The heart of any of these is the processor (CPU or CPU). It has a complex structure. To understand how the PC works, you should find out what is included in the processor.

Purpose and functions

Before studying the devices that are part of the processor, you should find out what it is intended for. So, the processor is the central device of the PC. Its purpose is:

• To control the work of the computer, following a given program;
• Perform information processing operations.

Devices included in the processor

At the moment, the CPU is a special integrated circuit.

The devices that make up the processor are:

• register;
• Cache memory;
• Data and address buses;
• ALU (arithmetic logic unit);
• Mathematical coprocessor.

Register

This is a block of memory cells that form ultra-fast RAM inside the CPU. It is used by itself and is not available to programmers. The amount of memory is only a few hundred bytes.

The CPU registers are divided into 2 types: general purpose and special.

Registers of the 1st type are used when logical and arithmetic type operations or operations of such additional instruction sets as SSE, MMX, etc. are performed.

Registers of the second type contain the system data required for the operation of the processor. These include control registers, system addresses, debugging, etc. Access to them is strictly regulated.

In addition, such devices include a command counter containing the address of the command to which the CPU will start at the next operation cycle.

Cache memory

The devices that make up the processor are quite diverse. This includes the cache. It is a super-operative memory. The purpose of its use is to speed up the work of the PC. To do this, when you access the CPU in memory, you first check whether the requested data is stored in the cache. For this purpose, compare the address of the incoming request with the values of all the cache tags where this data can be stored. Coincidence of the cache line with the tag is called a hit (cache hit). In the opposite case, a cache miss is fixed. Cache hit allows the processor to immediately read or write data on a line with a matching tag. The measure of cache efficiency for the chosen algorithm (program) is the ratio of the number of failed cache hits to the total number of processor requests to memory, called the hit rating.

ALU

Although some devices that are part of the processor have their own memory, the ALU is a special combination scheme without elements of its own memory. Its purpose is to implement the most important operations of the data processing process:

• Accepts 2 inputs for 2 inputs (contents of 2 registers, etc.);
• Forms and outputs the output of the operation.

It consists in performing a set of simple arithmetic operations (AO), divided into 3 main categories: logical, arithmetic and bit operations. AO is a data processing procedure (subtraction, addition, multiplication or division) whose arguments and results are numbers. They differ from logical operations. They are understood as procedures that build complex statements (AND, NOT, OR).

Arithmetic logic device consists of registers, control element and adder with logic circuits. It functions in accordance with the operation codes that are executed on variables that are placed in registers.

Data and address buses

These devices, which are part of the processor, are a set of conductors. The first of them is intended for transferring the address of the memory location into which the data is sent. For each of them, 1 bit is transmitted. It corresponds to 1 digit in the address. An increase in the number of conductors used to generate the address makes it possible to label a larger number of cells. The bus width determines the maximum amount of memory that can be addressed by the processor.

If the data bus is compared to a highway and counted as a bit-lane with the number of lanes, then the address bus is associated with street or house numbering. The number of its lines is equal to the number of digits (signs) in the house number. Thus, if on a particular street the house numbers consist of more than 2 decimal digits, then the number of houses located on it can not exceed 100 (ie 102). With 3-digit numbers, the number of possible addresses increases to 103.

The address and data buses are independent, and the chip designers choose their bit depths at their own discretion. At the same time, there are more digits in the data bus, the more they are in the address bus. Their bit depth is an indicator of the capabilities of a particular processor. In particular, in the data bus it determines the processor's ability to exchange information, and the width of the address bus indicates the amount of memory with which it can work.

Mathematical coprocessor

Continuing to consider what is included in the computer processor, we can not say a few words about this device. It is designed to extend the capabilities of the CPU and to provide its functionality through a module of so-called floating point operations, for processors that do not have an integrated module.

The mathematical coprocessor is not one of the mandatory elements of the PC, and it can be discarded. Previously, many manufacturers did so, based on considerations of economy.

However, in solving problems that require a lot of mathematical calculations (for scientific or engineering calculations), it was necessary to solve the problem of increasing the productivity of the PC.

If earlier the module of the mathematical coprocessor was installed on the motherboard as a separate chip, then in modern personal computers the use of this device in this format is not required, since it was originally built into the central processor.

Other PC Devices

A personal computer is a complex and coherent system.

All possible devices that are part of the computer, can not be listed in two words.

In addition to the processor, the PC also includes:

• Motherboard with a connector for connecting the CPU;
• Hard drives and flexible magnetic disks ;
• Power Supply;
• Memory;
• Compact disk and dvd drives;
• Connectors (ports) for additional devices, etc.

In addition, various peripheral devices are used, such as:

• computer mouse;
• keyboard;
• microphone;
• Speakers, etc.

Now you know that all the possible devices that make up the computer are parts of a complex system controlled by the processor. Its role can not be overemphasized, as the work of the PC depends on its normal functioning. At the moment, experts predict that in the coming decades the material part of the processors will undergo significant changes. This is due to the fact that the technological process will become obsolete, quantum computers, biological computers, etc. will replace the usual PC.