当前位置:网站首页>Memory and stack related concepts
Memory and stack related concepts
2022-07-06 05:46:00 【qq_ twenty-nine million five hundred and sixty-six thousand six】
Memory
The smallest storage unit in a computer is bytes , Memory is no exception , Each byte acts as a storage unit . In this way, the memory is divided into hundreds of millions of memory units , To facilitate the management of these units , The computer has chosen to number each memory unit , When you want to use a memory unit , Just specify the memory unit number ( Memory address ) that will do . In order to number as many addresses as possible , The computer uses a 4 Number of bytes to address memory , This is good for 2^32 Block memory for addressing , Each block is 1byte,2^32 byte = 4Gb, The memory size that can be addressed is 4G size .
Stack
When the program runs, it will not immediately allocate all memory for the program , Will initialize a certain size of memory area to the program , Memory blocks in this memory space can be used by programs , Used to store data in the program . This space is used from memory blocks with large addresses , To see which address memory unit is used by the current stack , stay ESP The current memory location used is recorded in the register , If you add a data , Will be added at this location , then ESP Continue to move forward one position . therefore ESP The current position of the register record , Is the position of the next data insertion . This pointer is called the stack top pointer , The pointer is added with the data (push) And take out (pop) Move . alike ,EBP The address of the beginning of a stack is recorded in , Become a pointer at the bottom of the stack , The address usually does not change , Only in opening up a new stack space , For example, when executing a function call , When you need to re record a new function space for a function , Will change the position of the bottom of the stack . But when changing the pointer at the bottom of the stack , The original position at the bottom of the stack will be put on the stack and saved , It is convenient to restore to the original bottom of the stack in the future .
Stack elevation
We know , In advanced languages , When we execute a function call , Will open up a new stack space , At this point, stack lifting is required , You need to change ESP and EBP Bottom of stack and bottom of stack pointer recorded in register , In this way, the value generated in the function will not affect the original stack space ( The yellow part ) The data of . The right figure shows the result of stack elevation , here push The data will come from 1005 Start adding ,pop Only to 1005 The data of this address , Can't go down any further pop, This will not affect the contents of the metastack .
Stack balance
Stack balancing is actually restoring stack contents , For example, when performing a function operation , Stack up , Open up new space for functions , When function execution ends , The bottom and top pointers should be restored to their original positions .
The brief process is
1. take ESP Value in register , Change to EBP Value , In this way, the top of the stack is at the current bottom of the stack .ESP=1005
2. take EBP Get the value in the memory address pointed to by the register , namely 1000, take EBP The value of the register is changed to this value 1000. such EBP Back to 1000 The location of .
Thus, the stack recovery is completed , Stack balance is achieved
Data width
There are three data widths in assembly language , Respectively
BYTE: One byte wide , Occupy 8 position
WORD: word , Two bytes wide , Occupy 16 position
DOUBLEWORD: Two words , Four byte width , Occupy 32 position .
Large and small end mode
Memory is addressed from small to large , When storing a multi byte data , If the small address of memory stores the high order of multi byte data , It's the big end model . in other words , First get the high bit of the data for storage , Then take the low order storage . For example, a string "abcd",a Is the high order of the data ,d It's low , The memory will take out four consecutive memory spaces to store this string . If this continuous memory is stored in a small address a And then in turn bcd, It's the big end model . If the low order data is stored in the small address , Small end mode .
It is up to the compiler to store the data in big end or small end mode .
add , All registers contain addresses
边栏推荐
- [QNX hypervisor 2.2 user manual]6.3.3 using shared memory (shmem) virtual devices
- Yunxiaoduo software internal test distribution test platform description document
- How to get list length
- Algorithm -- climbing stairs (kotlin)
- The ECU of 21 Audi q5l 45tfsi brushes is upgraded to master special adjustment, and the horsepower is safely and stably increased to 305 horsepower
- Winter 2021 pat class B problem solution (C language)
- 改善Jpopup以实现动态控制disable
- 59. Spiral matrix
- 【经验】UltralSO制作启动盘时报错:磁盘/映像容量太小
- 05. 博客项目之安全
猜你喜欢
华为路由器如何配置静态路由
ARTS Week 25
- [email protected] raspberry pie"/>
[email protected] raspberry pie
Game push image / table /cv/nlp, multi-threaded start
Application Security Series 37: log injection
03. Login of development blog project
Station B Liu Erden linear regression pytoch
Sequoiadb Lake warehouse integrated distributed database, June 2022 issue
Promise summary
[experience] install Visio on win11
随机推荐
The ECU of 21 Audi q5l 45tfsi brushes is upgraded to master special adjustment, and the horsepower is safely and stably increased to 305 horsepower
First knowledge database
05. Security of blog project
Vulhub vulnerability recurrence 72_ uWSGI
自建DNS服务器,客户端打开网页慢,解决办法
JS array list actual use summary
Problems encountered in installing mysql8 on MAC
Pay attention to the details of pytoch code, and it is easy to make mistakes
Application Security Series 37: log injection
Download, install and use NVM of node, and related use of node and NRM
Luogu [Beginner Level 4] array p1427 number game of small fish
29io stream, byte output stream continue write line feed
Anti shake and throttling are easy to understand
Station B, Master Liu Er - back propagation
02. Develop data storage of blog project
Web服务连接器:Servlet
初识数据库
【华为机试真题详解】统计射击比赛成绩
JDBC calls the stored procedure with call and reports an error
Classes and objects (I) detailed explanation of this pointer