What if you knew how computers work? The x86 Adventures series teaches you your computer's language - x86 Assembly language, from scratch. No prior knowledge is assumed. [Part 7] x86 Stringing Welcome to the seventh chapter of x86 Assembly Adventures. Have you ever wondered how text is represented inside the computer? We have dealt with lots of numbers, but how can we write anything useful to the user? Maybe you have so much to say to the world through your programs, and numbers are just not enough. Don't worry, we are going to cover it here. In this part we will learn how to represent text characters as numbers (ASCII code) and how to keep text in memory. (In the programming world, a sequence of text character is sometimes referred to as a string.) Next, we will meet a few x86 instructions that were specially designed to deal with text strings. Those are stos, lods and movs. We also discover the rep prefix, and use it together with our newly learned instructions to copy strings, search characters and more. Why learn x86 Assembly Language?
- You are the kind of person who really likes to know how things work. In this course you are going to get solid understanding on how computer programs work from the inside.
- Become a better programmer - Knowing how things work down there will help you take better decisions, even as a high level programmer. If you were always wondering what is the stack, or what are those pointers everyone talks about, you came to the right place.
- Write faster code - When you really want to get the most of your processor, writing in raw Assembly is needed. We are not going to talk about optimizations in this course, however you will get a solid foundations so that you can continue exploring on your own.
- You want to become a reverse engineer or a security researcher, read the code of viruses or look for software vulnerabilities. As most of the time the original source code will not be available to you, solid understanding of x86 Assembly Language is mandatory.
The course is made of video lectures. A lecture could be from a presentation, or a real world example, showing me doing stuff at the computer. Almost every video lecture is accompanied by some kind of exercise (You will be told during the lecture, don't worry :) ) The exercises are open source. They are attached here as a rar file, however you could also get them on github. (See "About this course" video for more information). It is crucial that you complete the exercises. You will learn a lot from the lectures, but it is pretty much a waste of your time and money if you don't do the exercises. (Or at least verify that you know how to do them, if you are more experienced). Course tech stack
No prior knowledge is assumed for this course, but I do assume some things regarding your system, so make sure that everything here describes you:
- You are using a Windows operation system. (The course videos use Windows 7). It is recommended to use at least Windows XP.
- You have an intel x86 processor. (If you don't know what you have then you have x86 processor, trust me).
For the tech savvy, some more details about the tools we are going to use in this course:
- Assembly flavour: x86 32 bits protected mode.
- Assembler: The Flat Assembler (FASM)
- Debugger: WinDbg.
? Most of the exercises were ported to linux, however the videos show me using windows 7. Contact me if you are not sure.