Concept and understanding of memory address

Introduction to this issue

This paper mainly introduces ： How memory is used , How memory addresses are generated , How to use memory address .

Catalog

• Memory
• Memory address
  • Origin of memory address
  • How memory addresses are generated
  • The size of a memory unit
• How to use memory address

Memory

Memory is a very important memory on a computer , Provide enough memory space for the operation of the system and software , Of course, all programs in the computer run in memory . But here's the thing , Memory is only used for temporary storage of programs and data , In case of power off or power failure , The program and data will be lost .

Memory is actually a large space , I can't just store a data in such a large space , Then how can we effectively use this space ？ So we divide the memory into small memory units , Each memory unit can store some data relatively independently . In this way, the memory can be used effectively .

Memory address

Origin of memory address

How to use these memory units ？ In fact, it's not hard to , Just number each memory cell , Then you can access the corresponding memory unit through these numbers . Do you think this method looks a bit like real life , The courier goes through your home address and finds you a little similar . So later we call the number of each memory unit ： Memory address .

How memory addresses are generated

We all know that when we buy computers, there will be 32 Bit and 64 Position , And here it is 32 Bit and 64 Bit actually refers to physical 32 root Address line and 64 root Address line , Since it's a wire, of course it can be energized , As long as the power is on, there will be Positive and negative Points ; In the electrical field, positive electricity will be used “1” To express , For negative electricity “0” To express , In this way, an incoming call signal can be converted into a digital signal . Now if there is one 32 Bit machine , Imagine being energized 32 The root address line will produce 32 individual “0” or “1” The sequence of components （ That is to say 32 Binary sequence of bits ）, And this 32 The binary sequence of bits will produce 2^32 A different result . Here's the picture ：

Then we might as well make these binary sequences into the number of each memory unit , Can that produce 2^32 A memory address ！ To store an address in memory, you need the corresponding memory space to store ,32 The address of bit needs 4 Bytes ,64 The address of bit needs 8 Bytes .

The size of a memory unit

We know that the smallest unit of storage capacity of a computer is bits （bit）, Next comes bytes （byte）、kb、mb、gb、tb、pb.

Which storage unit is suitable for the size of memory unit ？ Let's start with an account , If the memory unit capacity is 1 What is the size of the whole memory in bytes （2^32 Car ride 1 Bytes = 4,294,967,296‬ Bytes = 4,194,304（kb）= 4,096（mb）‬= 4（gb））, The calculated memory size coincides with the memory size on the market . So after analysis 1 Bytes are the most appropriate capacity as a memory unit .

How to use memory address

stay C There is an operator in the language “&”, You can directly find the memory address , So it's called ： Take the address symbol . We can take a look through the following procedure ：

#include<stdio.h>
int main()
{
    
	int a = 10;
	printf("%p\n", &a);
}

The result of printing is ：00BBf9EC, This is the shaping variable a Storage address , It's just using hexadecimal instead of binary to represent the address .

If this blog is helpful to you , Give bloggers a free like to show encouragement. Welcome to like comment collection ️, thank you ！！！
If you have any questions or different opinions , Welcome to the comment area .