Linux x86初学者指南：Assembly语言编程入门

5星 · 超过95%的资源需积分: 12 123 浏览量更新于2024-07-28 收藏 1.32MB PDF 举报

《从零开始编程：Linux平台上x86机器的汇编语言教程》是一本由Jonathan Bartlett编写的书籍，适合编程初学者和希望深入理解汇编语言但尚未掌握该领域的中级开发者。本书以AT&T汇编风格为基础，专为Linux平台设计，特别关注于那些其他入门教材中通常略过的主题。首先，作者以易懂的方式引导读者从基础入手，介绍了Linux环境下x86架构的汇编语言编程。书中涵盖了广泛的领域，包括但不限于： 1. **内存管理**：作者解释了如何在汇编层面理解内存分配和管理，这对于理解计算机系统的工作原理至关重要。 2. **调试技巧**：学习者将了解到如何在汇编程序中有效地定位和解决问题，这是提高编程技能的关键步骤。 3. **与C语言接口**：通过实例演示，读者能够了解如何在汇编和高级语言（如C）之间进行交互，这对于编写高效代码时的模块化编程十分有用。 4. **动态链接库**：书中介绍了如何利用动态链接库，这在构建大型软件项目时非常实用，有助于代码重用和模块化。 5. **GUI编程入门**：虽然不是详尽的教程，但本书至少提供了一些关于图形用户界面编程的基础概念，让读者对现代软件开发有更全面的认识。值得注意的是，由于这本书旨在作为入门教材，所以它可能不会深入探讨专业级的x86汇编细节，而是侧重于概念的讲解和实践技巧的培养。这意味着它不是一本用于专业程序员的参考书，而是为初学者提供一个循序渐进的学习路径，帮助他们理解汇编语言的工作原理以及编程逻辑。最后，作者强调版权许可，允许读者在遵循GNU自由文档许可证（GPLv1.1或更高版本）的前提下复制、分发和修改文档，并提供了源代码示例的使用权限。此外，对于商标的提及，表明所有标识符均归其所有者所有。如果你正寻求系统地学习汇编语言并将其与Linux环境结合，或者想深入了解底层编程，这本书无疑是一个很好的起点。购买链接也一并提供，以便读者获取实体书或电子版资源。

Chapter 2. Computer Architecture

decoder which ﬁgures out what the instruction means. This includes what process

needs to take place (addition, subtraction, multiplication, data movement, etc.) and

what memory locations are going to be involved in this process. Computer

instructions usually consist of both the actual instruction and the list of memory

locations that are used to carry it out.

Now the computer uses the data bus to fetch the memory locations to be used in

the calculation. The data bus is the connection between the CPU and memory. It is

the actual wire that connects them. If you look at the motherboard of the

computer, the wires that go out from the memory are your data bus.

In addition to the memory on the outside of the processor, the processor itself has

some special, high-speed memory locations called registers. There are two kinds

of registers - general registers and special-purpose registers. General-purpose

registers are where the main action happens. Addition, subtraction, multiplication,

comparisions, and other operations generally use general-purpose registers for

processing. However, computers have very few general-purpose registers. Most

information is stored in main memory, brought in to the registers for processing,

and then put back into memory when the processing is completed. special-purpose

registers are registers which have very speciﬁc purposes. We will discuss these as

we come to them.

Now that the CPU has retrieved all of the data it needs, it passes on the data and

the decoded instruction to the arithmetic and logic unit for further processing.

Here the instruction is actually executed. After the results of the computation have

been calculated, the results are then placed on the data bus and sent to the

appropriate location in memory or in a register, as speciﬁed by the instruction.

This is a very simpliﬁed explanation. Processors have advanced quite a bit in

recent years, and are now much more complex. Although the basic operation is

still the same, it is complicated by the use of cache hierarchies, superscalar

processors, pipelining, branch prediction, out-of-order execution, microcode

translation, coprocessors, and other optimizations. Don’t worry if you don’t know

what those words mean, you can just use them as Internet search terms if you want

Chapter 2. Computer Architecture

So what about if we need numbers larger than 255? We can simply use a

combination of bytes to represent larger numbers. Two bytes can be used to

represent any number between 0 and 65536. Four bytes can be used to represent

any number between 0 and 4294967295. Now, it is quite difﬁcult to write

programs to stick bytes together to increase the size of your numbers, and requires

a bit of math. Luckily, the computer will do it for us for numbers up to 4 bytes

long. In fact, four-byte numbers are what we will work with by default.

We mentioned earlier that in addition to the regular memory that the computer has,

it also has special-purpose storage locations called registers. Registers are what

the computer uses for computation. Think of a register as a place on your desk - it

holds things you are currently working on. You may have lots of information

tucked away in folders and drawers, but the stuff you are working on right now is

on the desk. Registers keep the contents of numbers that you are currently

manipulating.

On the computers we are using, registers are each four bytes long. The size of a

typical register is called a computer’s word size. x86 processors have four-byte

words. This means that it is most natural on these computers to do computations

four bytes at a time. This gives us roughly 4 billion values.

Addresses are also four bytes (1 word) long, and therefore also ﬁt into a register.

x86 processors can access up to 4294967296 bytes if enough memory is installed.

Notice that this means that we can store addresses the same way we store any

other number. In fact, the computer can’t tell the difference between a value that is

an address, a value that is a number, a value that is an ASCII code, or a value that

you have decided to use for another purpose. A number becomes an ASCII code

when you attempt to display it. A number becomes an address when you try to

look up the byte it points to. Take a moment to think about this, because it is

crucial to understanding how computer programs work.

Addresses which are stored in memory are also called pointers, because instead of

having a regular value in them, they point you to a different location in memory.

As we’ve mentioned, computer instructions are also stored in memory. In fact,

Chapter 2. Computer Architecture

they are stored exactly the same way that other data is stored. The only way the

computer knows that a memory location is an instruction is that a special-purpose

instruction pointer points to a memory word, it is loaded as an instruction. Other

than that, the computer has no way of knowing the difference between programs

and other types of data.

Interpreting Memory

Computers are very exact. Because they are exact, programmers have to be

equally exact. A computer has no idea what your program is supposed to do.

Therefore, it will only do exactly what you tell it to do. If you accidentally print

out a regular number instead of the ASCII codes that make up the number’s digits,

the computer will let you - and you will wind up with jibberish on your screen (it

will try to look up what your number represents in ASCII and print that). If you

tell the computer to start executing instructions at a location containing data

instead of program instructions, who knows how the computer will interpret that -

but it will certainly try. The computer will execute your instructions in the exact

order you specify, even if it doesn’t make sense.

The point is, the computer will do exactly what you tell it, no matter how little

sense it makes. Therefore, as a programmer, you need to know exactly how you

have your data arranged in memory. Remember, computers can only store

numbers, so letters, pictures, music, web pages, documents, and anything else are

just long sequences of numbers in the computer, which particular programs know

how to interpret.

For example, say that you wanted to store customer information in memory. One

way to do so would be to set a maximum size for the customer’s name and address

- say 50 ASCII characters for each, which would be 50 bytes for each. Then, after

2. Note that here we are talking about general computer theory. Some processors and op-

erating systems actually mark the regions of memory that can be executed with a special

marker that indicates this.

剩余325页未读，继续阅读

大盈

粉丝: 2
资源: 8

Linux x86初学者指南：Assembly语言编程入门

COM+ programming from the ground up

Programming from Ground up

Programming from the Ground Up

how to extract the words from a pdf paper in python programming

Could not find a version that satisfies the requirement yaml (from versio ns: none)

the go programming language pdf

the c programming language pdf

file_version_info = win32api.GetFileVersionInfo(file_path, '\\')

extract word from a pdf file using tesseract-ocr in python programming

最新资源