First, some background 首先，一些背景

Assembly language is bare-bones. The only interface a programmer has above the actual hardware is the kernel itself. In order to build useful programs in assembly we need to use the linux system calls provided by the kernel. These system calls are a library built into the operating system to provide functions such as reading input from a keyboard and writing output to the screen.
汇编语言是基本的。程序员在实际硬件之上的唯一接口是内核本身。为了在汇编中构建有用的程序，我们需要使用内核提供的 linux 系统调用。这些系统调用是操作系统中内置的库，用于提供从键盘读取输入和将输出写入屏幕等功能。

When you invoke a system call the kernel will immediately suspend execution of your program. It will then contact the necessary drivers needed to perform the task you requested on the hardware and then return control back to your program.
当您调用系统调用时，内核将立即暂停程序的执行。然后，它将联系在硬件上执行您请求的任务所需的必要驱动程序，然后将控制权交还给您的程序。

Note: Drivers are called drivers because the kernel literally uses them to drive the hardware.
注意：驱动程序之所以被称为驱动程序，是因为内核实际上使用它们来驱动硬件。

We can accomplish this all in assembly by loading EAX with the function number (operation code OPCODE) we want to execute and filling the remaining registers with the arguments we want to pass to the system call. A software interrupt is requested with the INT instruction and the kernel takes over and calls the function from the library with our arguments. Simple.
我们可以在汇编中完成这一切，方法是用我们想要执行的函数号（操作代码 OPCODE）加载 EAX，并用我们想要传递给系统调用的参数填充剩余的寄存器。使用 INT 指令请求软件中断，内核接管并使用我们的参数从库中调用函数。简单。

For example requesting an interrupt when EAX=1 will call sys_exit and requesting an interrupt when EAX=4 will call sys_write instead. EBX, ECX & EDX will be passed as arguments if the function requires them. Click here to view an example of a Linux System Call Table and its corresponding OPCODES.
例如，当 EAX=1 将调用 sys_exit 时请求中断，而当 EAX=4 将调用 sys_write 时请求中断。如果函数需要，EBX、ECX和EDX将作为参数传递。单击此处查看 Linux 系统调用表及其相应 OPCODES 的示例。

Writing our program 编写我们的程序

Firstly we create a variable 'msg' in our .data section and assign it the string we want to output in this case 'Hello, world!'. In our .text section we tell the kernel where to begin execution by providing it with a global label _start: to denote the programs entry point.
首先，我们在 .data 部分创建一个变量 'msg'，并为其分配我们想要输出的字符串，在本例中为 'Hello， world！'。在我们的 .text 部分中，我们通过为内核提供一个全局标签 _start： 来表示程序入口点，从而告诉内核从哪里开始执行。

We will be using the system call sys_write to output our message to the console window. This function is assigned OPCODE 4 in the Linux System Call Table. The function also takes 3 arguments which are sequentially loaded into EDX, ECX and EBX before requesting a software interrupt which will perform the task.
我们将使用 system 调用 sys_write将我们的消息输出到控制台窗口。此函数在 Linux 系统调用表中被分配为 OPCODE 4。该函数还接受 3 个参数，这些参数在请求执行任务的软件中断之前按顺序加载到 EDX、ECX 和 EBX 中。

The arguments passed are as follows:
传递的参数如下：

• EDX will be loaded with the length (in bytes) of the string.
  EDX 将加载字符串的长度（以字节为单位）。
• ECX will be loaded with the address of our variable created in the .data section.
  ECX 将加载在 .data 部分中创建的变量的地址。
• EBX will be loaded with the file we want to write to – in this case STDOUT.
  EBX 将加载我们想要写入的文件 – 在本例中为 STDOUT。

We compile, link and run the program using the commands below.
我们使用以下命令编译、链接和运行程序。

Error: Segmentation fault
错误：分段错误

Some more background 更多背景

After successfully learning how to execute a system call in Lesson 1 we now need to learn about one of the most important system calls in the kernel, sys_exit.
在第 1 课中成功学习如何执行系统调用后，我们现在需要了解内核中最重要的系统调用之一 sys_exit。

Notice how after our 'Hello, world!' program ran we got a Segmentation fault? Well, computer programs can be thought of as a long strip of instructions that are loaded into memory and divided up into sections (or segments). This general pool of memory is shared between all programs and can be used to store variables, instructions, other programs or anything really. Each segment is given an address so that information stored in that section can be found later.
注意到我们的 'Hello， world！' 程序运行后，我们是怎么遇到 Segmentation 错误的吗？嗯，计算机程序可以被认为是一条长条指令，这些指令被加载到内存中并分为多个部分（或段）。这个通用内存池在所有程序之间共享，可用于存储变量、指令、其他程序或任何实际内容。每个区段都有一个地址，以便以后可以找到存储在该区段中的信息。

To execute a program that is loaded in memory, we use the global label _start: to tell the operating system where in memory our program can be found and executed. Memory is then accessed sequentially following the program logic which determines the next address to be accessed. The kernel jumps to that address in memory and executes it.
要执行加载到内存中的程序，我们使用全局标签 _start： 来告诉操作系统可以在内存中的哪个位置找到和执行我们的程序。然后按照程序逻辑顺序访问内存，该程序逻辑确定要访问的下一个地址。内核跳转到内存中的该地址并执行它。

It's important to tell the operating system exactly where it should begin execution and where it should stop. In Lesson 1 we didn't tell the kernel where to stop execution. So, after we called sys_write the program continued sequentially executing the next address in memory, which could have been anything. We don't know what the kernel tried to execute but it caused it to choke and terminate the process for us instead - leaving us the error message of 'Segmentation fault'. Calling sys_exit at the end of all our programs will mean the kernel knows exactly when to terminate the process and return memory back to the general pool thus avoiding an error.
请务必告诉操作系统它应该从哪里开始执行，应该从哪里停止。在第 1 课中，我们没有告诉内核在何处停止执行。因此，在我们调用 sys_write 后，程序继续按顺序执行内存中的下一个地址，该地址可以是任何内容。我们不知道内核试图执行什么，但它导致它窒息并为我们终止了进程 - 给我们留下了“Segmentation fault”的错误消息。在所有程序结束时调用 sys_exit 意味着内核确切地知道何时终止进程并将内存返回给通用池，从而避免错误。

Writing our program 编写我们的程序

Sys_exit has a simple function definition. In the Linux System Call Table it is allocated OPCODE 1 and is passed a single argument through EBX.
Sys_exit 具有一个简单的函数定义。在 Linux 系统调用表中，它被分配为 OPCODE 1，并通过 EBX 传递单个参数。

In order to execute this function all we need to do is:
为了执行此函数，我们需要做的就是：

• Load EBX with 0 to pass zero to the function meaning 'zero errors'.
  加载 EBX 0 以将零传递给函数，表示“零错误”。
• Load EAX with 1 to call sys_exit.
  加载 EAX 1 以调用 sys_exit。
• Then request an interrupt on libc using INT 80h.
  然后使用 INT 80h 在 libc 上请求中断。

We then compile, link and run it again.
然后我们编译、链接并再次运行它。

Note: Only new code added in each lesson will be commented.
注意：只会注释每节课中添加的新代码。

Firstly, some background 首先，一些背景

Why do we need to calculate the length of a string?
为什么我们需要计算字符串的长度？

Well sys_write requires that we pass it a pointer to the string we want to output in memory and the length in bytes we want to print out. If we were to modify our message string we would have to update the length in bytes that we pass to sys_write as well, otherwise it will not print correctly.
嗯sys_write要求我们向它传递一个指针，指向我们想要在内存中输出的字符串和我们想要打印出来的长度（以字节为单位）。如果我们要修改我们的消息字符串，我们也必须更新我们传递给 sys_write 的长度（以字节为单位），否则它将无法正确打印。

You can see what I mean using the program in Lesson 2. Modify the message string to say 'Hello, brave new world!' then compile, link and run the new program. The output will be 'Hello, brave ' (the first 13 characters) because we are still only passing 13 bytes to sys_write as its length. It will be particularly necessary when we want to print out user input. As we won't know the length of the data when we compile our program, we will need a way to calculate the length at runtime in order to successfully print it out.
您可以在第 2 课中了解我使用该程序的含义。修改消息字符串以表示 'Hello， brave new world！'，然后编译、链接并运行新程序。输出将是 'Hello， brave '（前 13 个字符），因为我们仍然只将 13 个字节作为其长度传递给 sys_write。当我们想要打印出用户输入时，这将特别必要。由于我们在编译程序时不知道数据的长度，因此我们需要一种方法来计算运行时的长度，以便成功打印出来。

Writing our program 编写我们的程序

To calculate the length of the string we will use a technique called pointer arithmetic. Two registers are initialised pointing to the same address in memory. One register (in this case EAX) will be incremented forward one byte for each character in the output string until we reach the end of the string. The original pointer will then be subtracted from EAX. This is effectively like subtraction between two arrays and the result yields the number of elements between the two addresses. This result is then passed to sys_write replacing our hard coded count.
为了计算字符串的长度，我们将使用一种称为指针算术的技术。两个 registers 被初始化，指向内存中的相同地址。一个寄存器（在本例中为 EAX）将为输出字符串中的每个字符向前增加一个字节，直到我们到达字符串的末尾。然后，将从 EAX 中减去原始指针。这实际上就像两个数组之间的减法，结果会产生两个地址之间的元素数。然后，此结果将传递给 sys_write 替换我们的硬编码计数。

The CMP instruction compares the left hand side against the right hand side and sets a number of flags that are used for program flow. The flag we're checking is the ZF or Zero Flag. When the byte that EAX points to is equal to zero the ZF flag is set. We then use the JZ instruction to jump, if the ZF flag is set, to the point in our program labeled 'finished'. This is to break out of the nextchar loop and continue executing the rest of the program.
CMP 指令将左侧与右侧进行比较，并设置许多用于程序流的标志。我们正在检查的标志是 ZF 或 Zero Flag。当 EAX 指向的字节等于零时，设置 ZF 标志。然后，如果设置了 ZF 标志，我们使用 JZ 指令跳转到程序中标记为 'finished' 的点。这是为了跳出 nextchar 循环并继续执行程序的其余部分。

Introduction to subroutines
子例程简介

Subroutines are functions. They are reusable pieces of code that can be called by your program to perform various repeatable tasks. Subroutines are declared using labels just like we've used before (eg. _start:) however we don't use the JMP instruction to get to them - instead we use a new instruction CALL. We also don't use the JMP instruction to return to our program after we have run the function. To return to our program from a subroutine we use the instruction RET instead.
子例程是函数。它们是可重用的代码段，程序可以调用这些代码来执行各种可重复的任务。子例程使用标签进行声明，就像我们之前使用的那样（例如 _start：），但是我们不使用 JMP 指令来访问它们 - 而是使用新的指令 CALL。在运行函数后，我们也不会使用 JMP 指令返回到我们的程序。要从子例程返回我们的程序，我们改用指令 RET。

Why don't we JMP to subroutines?
为什么我们不对子例程进行 JMP 呢？

The great thing about writing a subroutine is that we can reuse it. If we want to be able to use the subroutine from anywhere in the code we would have to write some logic to determine where in the code we had jumped from and where we should jump back to. This would litter our code with unwanted labels. If we use CALL and RET however, assembly handles this problem for us using something called the stack.
编写子例程的伟大之处在于我们可以重用它。如果我们希望能够从代码中的任何位置使用子例程，则必须编写一些逻辑来确定我们从代码中的哪个位置跳转，以及应该跳回到哪里。这将使我们的代码中充斥着不需要的标签。但是，如果我们使用 CALL 和 RET，assembly 会使用称为堆栈的东西为我们处理这个问题。

Introduction to the stack
堆栈简介

The stack is a special type of memory. It's the same type of memory that we've used before however it's special in how it is used by our program. The stack is what is call Last In First Out memory (LIFO). You can think of the stack like a stack of plates in your kitchen. The last plate you put on the stack is also the first plate you will take off the stack next time you use a plate.
堆栈是一种特殊类型的内存。它与我们之前使用的内存类型相同，但它在我们的程序使用方式上很特殊。该堆栈就是所谓的 Last In First Out 内存 （LIFO）。您可以将堆栈想象成厨房中的一堆盘子。您放在堆栈上的最后一个盘子也是您下次使用盘子时从堆栈中取出的第一个盘子。

The stack in assembly is not storing plates though, its storing values. You can store a lot of things on the stack such as variables, addresses or other programs. We need to use the stack when we call subroutines to temporarily store values that will be restored later.
但是，assembly 中的 stack 不是存储板，而是存储值。您可以在堆栈上存储很多东西，例如变量、地址或其他程序。当我们调用子例程时，我们需要使用堆栈来临时存储稍后将恢复的值。

Any register that your function needs to use should have it's current value put on the stack for safe keeping using the PUSH instruction. Then after the function has finished it's logic, these registers can have their original values restored using the POP instruction. This means that any values in the registers will be the same before and after you've called your function. If we take care of this in our subroutine we can call functions without worrying about what changes they're making to our registers.
您的函数需要使用的任何 register 都应该将其当前值放在堆栈上，以便使用 PUSH 指令安全保存。然后在函数完成其 logic之后，这些 registers 可以使用 POP 指令恢复其原始值。这意味着 registers 中的任何值在您调用函数之前和之后都是相同的。如果我们在子例程中处理到这个问题，我们就可以调用函数，而不必担心它们对我们的寄存器进行了哪些更改。

The CALL and RET instructions also use the stack. When you CALL a subroutine, the address you called it from in your program is pushed onto the stack. This address is then popped off the stack by RET and the program jumps back to that place in your code. This is why you should always JMP to labels but you should CALL functions.
CALL 和 RET 指令也使用堆栈。当你 CALL 一个子例程时，你在程序中调用它的地址被压入堆栈。然后，RET 从堆栈中弹出此地址，程序跳回到代码中的该位置。这就是为什么您应该始终对标签进行 JMP，但您应该 CALL 函数。

External include files allow us to move code from our program and put it into separate files. This technique is useful for writing clean, easy to maintain programs. Reusable bits of code can be written as subroutines and stored in separate files called libraries. When you need a piece of logic you can include the file in your program and use it as if they are part of the same file.
外部包含文件允许我们从程序中移动代码并将其放入单独的文件中。此技术对于编写干净、易于维护的程序非常有用。可重用的代码位可以编写为子例程，并存储在称为 libraries 的单独文件中。当您需要一段 logic 时，可以将该文件包含在程序中，并像使用它们一样使用它，就好像它们是同一个文件的一部分一样。

In this lesson we will move our string length calculating subroutine into an external file. We fill also make our string printing logic and program exit logic a subroutine and we will move them into this external file. Once it's completed our actual program will be clean and easier to read.
在本课中，我们将把字符串长度计算子例程移动到外部文件中。我们还将字符串打印逻辑和程序退出逻辑设置为子例程，并将它们移动到此外部文件中。一旦完成，我们的实际程序将变得干净且更易于阅读。

We can then declare another message variable and call our print function twice in order to demonstrate how we can reuse code.
然后，我们可以声明另一个 message 变量并调用我们的 print 函数两次，以演示如何重用代码。

Note: I won't be showing the code in functions.asm after this lesson unless it changes. It will just be included if needed.
注意：在这节课之后，我不会在 functions.asm 中显示代码，除非它发生更改。如果需要，它只会被包括在内。

Error: Our second message is outputted twice. This is fixed in the next lesson.
错误：我们的第二条消息输出两次。此问题将在下一课中修复。

Ok so why did our second message print twice when we only called our sprint function on msg2 once? Well actually it did only print once. You can see what I mean if you comment out our second call to sprint. The output will be both of our message strings.
好的，那么为什么我们只在 msg2 上调用了一次 sprint 函数，而我们的第二条消息打印了两次呢？嗯，实际上它只打印了一次。如果你把我们对 sprint 的第二次调用注释掉，你就会明白我的意思。输出将是我们的两个消息字符串。

But how is this possible?
但这怎么可能呢？

What is happening is we weren't properly terminating our strings. In assembly, variables are stored one after another in memory so the last byte of our msg1 variable is right next to the first byte of our msg2 variable. We know our string length calculation is looking for a zero byte so unless our msg2 variable starts with a zero byte it keeps counting as if it's the same string (and as far as assembly is concerned it is the same string). So we need to put a zero byte or 0h after our strings to let assembly know where to stop counting.
发生的事情是我们没有正确地终止我们的字符串。在汇编中，变量一个接一个地存储在内存中，因此 msg1 变量的最后一个字节紧挨着 msg2 变量的第一个字节。我们知道我们的字符串长度计算正在寻找一个零字节，因此除非我们的 msg2 变量以零字节开头，否则它会一直计数，就好像它是同一个字符串一样（就汇编而言，它是同一个字符串）。所以我们需要在字符串后面放一个 0 字节或 0h，让 assembly 知道在哪里停止计数。

Note: In programming 0h denotes a null byte and a null byte after a string tells assembly where it ends in memory.
注意：在编程中，0h 表示一个 null 字节和一个 null 字节，字符串后告诉 assembly 它在内存中的结束位置。

Linefeeds are essential to console programs like our 'hello world' program. They become even more important once we start building programs that require user input. But linefeeds can be a pain to maintain. Sometimes you will want to include them in your strings and sometimes you will want to remove them. If we continue to hard code them in our variables by adding 0Ah after our declared message text, it will become a problem. If there's a place in the code that we don't want to print out the linefeed for that variable we will need to write some extra logic remove it from the string at runtime.
换行符对于控制台程序（如我们的“你好世界”程序）至关重要。一旦我们开始构建需要用户输入的程序，它们就变得更加重要。但是维护换行可能很痛苦。有时你会想把它们包含在你的字符串中，有时你会想删除它们。如果我们继续在变量中对它们进行硬编码，在声明的消息文本后添加 0Ah，这将成为一个问题。如果代码中有一个地方我们不想打印出该变量的换行符，我们将需要编写一些额外的逻辑：在运行时将其从字符串中删除。

It would be better for the maintainability of our program if we write a subroutine that will print out our message and then print a linefeed afterwards. That way we can just call this subroutine when we need the linefeed and call our current sprint subroutine when we don't.
如果我们编写一个子例程来打印我们的消息，然后打印换行符，那对程序的可维护性会更好。这样，我们可以在需要换行时调用此子例程，并在不需要时调用当前的 sprint 子例程。

A call to sys_write requires we pass a pointer to an address in memory of the string we want to print so we can't just pass a linefeed character (0Ah) to our print function. We also don't want to create another variable just to hold a linefeed character so we will instead use the stack.
对 sys_write 的调用要求我们将指针传递给要打印的字符串内存中的地址，因此我们不能只将换行符 （0Ah） 传递给我们的 print 函数。我们也不想创建另一个变量来保存换行字符，因此我们将改用堆栈。

The way it works is by moving a linefeed character into EAX. We then push EAX onto the stack and get the address pointed to by the Extended Stack Pointer. ESP is another register. When you push items onto the stack, ESP is decremented to point to the address in memory of the last item and so it can be used to access that item directly from the stack. Since ESP points to an address in memory of a character, sys_write will be able to use it to print.
它的工作方式是将换行字符移动到 EAX 中。然后，我们将 EAX 推送到堆栈上，并获取 Extended Stack Pointer 指向的地址。ESP 是另一个寄存器。当您将项目推送到堆栈上时，ESP 会递减以指向内存中最后一项的地址，因此它可以用于直接从堆栈访问该项目。由于 ESP 指向字符内存中的地址，因此sys_write将能够使用它来打印。

Note: I've highlighted the new code in functions.asm below.
注意：我在下面的 functions.asm 中突出显示了新代码。

Passing arguments to your program from the command line is as easy as popping them off the stack in NASM. When we run our program, any passed arguments are loaded onto the stack in reverse order. The name of the program is then loaded onto the stack and lastly the total number of arguments is loaded onto the stack. The last two stack items for a NASM compiled program are always the name of the program and the number of passed arguments.
从命令行将参数传递给程序就像在 NASM 中将它们从堆栈中弹出一样简单。当我们运行程序时，任何传递的参数都会以相反的顺序加载到堆栈上。然后将程序的名称加载到堆栈上，最后将参数总数加载到堆栈上。NASM 编译程序的最后两个堆栈项始终是程序的名称和传递的参数的数量。

So all we have to do to use them is pop the number of arguments off the stack first, then iterate once for each argument and perform our logic. In our program that means calling our print function.
因此，要使用它们，我们所要做的就是先从堆栈中弹出参数的数量，然后为每个参数迭代一次并执行我们的逻辑。在我们的程序中，这意味着调用我们的 print 函数。

Note: We are using the ECX register as our counter for the loop. Although it's a general-purpose register it's original intention was to be used as a counter.
注意：我们使用 ECX 寄存器作为循环的计数器。虽然它是一个通用寄存器，但它的初衷是用作计数器。

Introduction to the .bss section
.bss 部分简介

So far we've used the .text and .data section so now it's time to introduce the .bss section. BSS stands for Block Started by Symbol. It is an area in our program that is used to reserve space in memory for uninitialised variables. We will use it to reserve some space in memory to hold our user input since we don't know how many bytes we'll need to store.
到目前为止，我们已经使用了 .text 和 .data 部分，现在是时候介绍 .bss 部分了。BSS 代表 Block Started by Symbol。它是我们程序中的一个区域，用于在内存中为未初始化的变量保留空间。我们将使用它在内存中保留一些空间来保存我们的用户输入，因为我们不知道需要存储多少字节。

The syntax to declare variables is as follows:
声明变量的语法如下：

Writing our program 编写我们的程序

We will be using the system call sys_read to receive and process input from the user. This function is assigned OPCODE 3 in the Linux System Call Table. Just like sys_write this function also takes 3 arguments which will be loaded into EDX, ECX and EBX before requesting a software interrupt that will call the function.
我们将使用 system 调用 sys_read 来接收和处理用户的输入。此函数在 Linux 系统调用表中被分配为 OPCODE 3。就像 sys_write 一样，此函数也接受 3 个参数，这些参数将在请求调用该函数的软件中断之前加载到 EDX、ECX 和 EBX 中。

The arguments passed are as follows:
传递的参数如下：

• EDX will be loaded with the maximum length (in bytes) of the space in memory.
  EDX 将加载内存中空间的最大长度（以字节为单位）。
• ECX will be loaded with the address of our variable created in the .bss section.
  ECX 将加载在 .bss 部分中创建的变量的地址。
• EBX will be loaded with the file we want to read from – in this case STDIN.
  EBX 将加载我们想要读取的文件 – 在本例中为 STDIN。

When sys_read detects a linefeed, control returns to the program and the users input is located at the memory address you passed in ECX.
当 sys_read 检测到换行时，控制权将返回给程序，并且用户输入位于您在 ECX 中传递的内存地址。

Firstly, some background 首先，一些背景

Counting by numbers is not as straight forward as you would think in assembly. Firstly we need to pass sys_write an address in memory so we can't just load our register with a number and call our print function. Secondly, numbers and strings are very different things in assembly. Strings are represented by what are called ASCII values. ASCII stands for American Standard Code for Information Interchange. A good reference for ASCII can be found here. ASCII was created as a way to standardise the representation of strings across all computers.
按数字计数并不像您在组装中想象的那么简单。首先，我们需要sys_write 个内存中的地址传递一个地址，这样我们就不能只用数字加载我们的寄存器并调用我们的 print 函数。其次，数字和字符串在组装中是非常不同的东西。字符串由所谓的 ASCII 值表示。ASCII 代表美国信息交换标准代码。可以在此处找到 ASCII 的良好参考。ASCII 的创建是为了标准化所有计算机上字符串的表示。

Remember, we can't print a number - we have to print a string. In order to count to 10 we will need to convert our numbers from standard integers to their ASCII string representations. Have a look at the ASCII values table and notice that the string representation for the number '1' is actually '49' in ASCII. In fact, adding 48 to our numbers is all we have to do to convert them from integers to their ASCII string representations.
请记住，我们不能打印数字 - 我们必须打印字符串。为了数到 10，我们需要将数字从标准整数转换为它们的 ASCII 字符串表示形式。查看 ASCII 值表，请注意数字 '1' 的字符串表示形式实际上是 ASCII 中的 '49'。事实上，我们将数字加 48 就是将它们从整数转换为 ASCII 字符串表示所需要做的。

Writing our program 编写我们的程序

What we will do with our program is count from 1 to 10 using the ECX register. We will then add 48 to our counter to convert it from a number to it's ASCII string representation. We will then push this value to the stack and call our print function passing ESP as the memory address to print from. Once we have finished counting to 10 we will exit our counting loop and call our quit function.
我们将对程序执行的操作是使用 ECX 寄存器从 1 到 10 的计数。然后，我们将 48 添加到计数器中，将其从数字转换为 ASCII 字符串表示形式。然后，我们将此值推送到堆栈中，并调用我们的 print 函数，将 ESP 作为要从中打印的内存地址传递。一旦我们完成计数到 10，我们将退出计数循环并调用我们的 quit 函数。

Error: Our number 10 prints a colon (:) character instead. What's going on?
错误：我们的数字 10 打印了一个冒号 （:) 字符。这是怎么回事？

So why did our program in Lesson 10 print out a colon character instead of the number 10?. Well lets have a look at our ASCII table. We can see that the colon character has a ASCII value of 58. We were adding 48 to our integers to convert them to their ASCII string representations so instead of passing sys_write the value '58' to print ten we actually need to pass the ASCII value for the number 1 followed by the ASCII value for the number 0. Passing sys_write '4948' is the correct string representation for the number '10'. So we can't just simply add 48 to our numbers to convert them, we first have to divide them by 10 because each place value needs to be converted individually.
那么，为什么我们在第 10 课中的程序打印出冒号字符而不是数字 10呢？好吧，让我们看看我们的 ASCII 表。我们可以看到冒号字符的 ASCII 值为 58。我们将 48 添加到整数中以将它们转换为 ASCII 字符串表示形式，因此我们实际上需要传递数字 1 的 ASCII 值，然后传递数字 0 的 ASCII 值，而不是sys_write传递值 '58' 来打印 10。传递 '4948' sys_write是数字 '10' 的正确字符串表示形式。因此，我们不能简单地将 48 添加到数字中来转换它们，我们首先必须将它们除以 10，因为每个位值都需要单独转换。

We will write 2 new subroutines in this lesson 'iprint' and 'iprintLF'. These functions will be used when we want to print ASCII string representations of numbers. We achieve this by passing the number in EAX. We then initialise a counter in ECX. We will repeatedly divide the number by 10 and each time convert the remainder to a string by adding 48. We will then push this onto the stack for later use. Once we can no longer divide the number by 10 we will enter our second loop. In this print loop we will print the now converted string representations from the stack and pop them off. Popping them off the stack moves ESP forward to the next item on the stack. Each time we print a value we will decrease our counter ECX. Once all numbers have been converted and printed we will return to our program.
在本课中，我们将编写 2 个新的子例程 'iprint' 和 'iprintLF'。当我们想要打印数字的 ASCII 字符串表示时，将使用这些函数。我们通过在 EAX 中传递数字来实现这一点。然后我们在 ECX 中初始化一个计数器。我们将重复将数字除以 10，每次通过添加 48 将余数转换为字符串。然后，我们会将其推送到堆栈上以供以后使用。一旦我们无法再将数字除以 10，我们将进入第二个循环。在这个打印循环中，我们将从堆栈中打印现在转换的字符串表示并将它们弹出。将它们从堆栈中弹出会将 ESP 向前移动到堆栈上的下一个项目。每次我们打印一个值时，我们都会减少我们的计数器 ECX。转换并打印所有号码后，我们将返回我们的程序。

How does the divide instruction work?
divide 指令如何运作？

The DIV and IDIV instructions work by dividing whatever is in EAX by the value passed to the instruction. The quotient part of the value is left in EAX and the remainder part is put into EDX (Originally called the data register).
DIV 和 IDIV 指令的工作原理是将 EAX 中的任何内容除以传递给指令的值。该值的商部分留在 EAX 中，其余部分放入 EDX （最初称为数据寄存器）。

For example. 例如。

If we are only storing the remainder won't we have problems?
如果我们只存储剩余部分，我们不会有问题吗？

No, because these are integers, when you divide a number by an even bigger number the quotient in EAX is 0 and the remainder is the number itself. This is because the number divides zero times leaving the original value as the remainder in EDX. How good is that?
不，因为这些是整数，所以当您将一个数字除以更大的数字时，EAX 中的商是 0，余数是数字本身。这是因为该数字除以零次，在 EDX 中留下原始值作为余数。那有多好？

Note: Only the new functions iprint and iprintLF have comments.
注意：只有新函数 iprint 和 iprintLF 有注释。

In this program we will be adding the registers EAX and EBX together and we'll leave our answer in EAX. Firstly we use the MOV instruction to load EAX with an integer (in this case 90). We then MOV an integer into EBX (in this case 9). Now all we need to do is use the ADD instruction to perform our addition. EBX & EAX will be added together leaving our answer in the left most register in this instruction (in our case EAX). Then all we need to do is call our integer printing function to complete the program.
在这个程序中，我们将把寄存器 EAX 和 EBX 一起添加，我们将把我们的答案留在 EAX 中。首先，我们使用 MOV 指令加载带有整数（在本例中为 90）的 EAX。然后我们将一个整数移动到 EBX 中（在本例中为 9）。现在我们需要做的就是使用 ADD 指令来执行我们的加法。EBX和EAX将被加在一起，使我们的答案在此指令的最左边寄存器中（在我们的例子中是EAX）。然后我们需要做的就是调用我们的整数打印函数来完成程序。

In this program we will be subtracting the value in the register EBX from the value in the register EAX. Firstly we load EAX and EBX with integers in the same way as Lesson 12. The only difference is we will be using the SUB instruction to perform our subtraction logic, leaving our answer in the left most register of this instruction (in our case EAX). Then all we need to do is call our integer printing function to complete the program.
在这个程序中，我们将从寄存器 EAX 中的值中减去寄存器 EBX 中的值。首先，我们按照与第 12 课相同的方式加载带有整数的 EAX 和 EBX。唯一的区别是我们将使用 SUB 指令来执行我们的减法逻辑，将我们的答案留在该指令的最左侧寄存器（在我们的例子中为 EAX）。然后我们需要做的就是调用我们的整数打印函数来完成程序。

In this program we will be multiplying the value in EBX by the value present in EAX. Firstly we load EAX and EBX with integers in the same way as Lesson 12. This time though we will be calling the MUL instruction to perform our multiplication logic. The MUL instruction is different from many instructions in NASM, in that it only accepts one further argument. The MUL instruction always multiples EAX by whatever value is passed after it. The answer is left in EAX.
在这个程序中，我们将 EBX 中的值乘以 EAX 中的值。首先，我们按照与第 12 课相同的方式加载带有整数的 EAX 和 EBX。不过，这一次，我们将调用 MUL 指令来执行我们的乘法逻辑。MUL 指令与 NASM 中的许多指令不同，因为它只接受一个进一步的参数。MUL 指令始终将 EAX 乘以在其之后传递的任何值。答案留在 EAX 中。

In this program we will be dividing the value in EBX by the value present in EAX. We've used division before in our integer print subroutine. Our program requires a few extra strings in order to print out the correct answer but otherwise there's nothing complicated going on.
在这个程序中，我们将 EBX 中的值除以 EAX 中的值。我们之前在 integer print 子例程中使用过 division。我们的程序需要一些额外的字符串才能打印出正确答案，但除此之外没有什么复杂的事情。

Firstly we load EAX and EBX with integers in the same way as Lesson 12. Division logic is performed using the DIV instruction. The DIV instruction always divides EAX by the value passed after it. It will leave the quotient part of the answer in EAX and put the remainder part in EDX (the original data register). We then MOV and call our strings and integers to print out the correct answer.
首先，我们按照与第 12 课相同的方式加载带有整数的 EAX 和 EBX。除法 logic 使用 DIV 指令执行。DIV 指令始终将 EAX 除以在其之后传递的值。它将答案的商部分留在 EAX 中，并将剩余部分放在 EDX （原始数据寄存器）中。然后我们 MOV 并调用我们的字符串和整数来打印出正确答案。

Our program will take several command line arguments and add them together printing out the result in the terminal.
我们的程序将获取几个命令行参数并将它们添加在一起，在终端中打印出结果。

Writing our program 编写我们的程序

Our program begins by using the POP instruction to get the number of passed arguments off the stack. This value is stored in ECX (originally known as the counter register). It will then POP the next value off the stack containing the program name and remove it from the number of arguments stored in ECX. It will then loop through the rest of the arguments popping each one off the stack and performing our addition logic. As we know, arguments passed via the command line are received by our program as strings. Before we can add the arguments together we will need to convert them to integers otherwise our result will not be correct. We do this by calling our Ascii to Integer function (atoi). This function will convert the ascii value into an integer and place the result in EAX. We can then add this value to EDX (originally known as the data register) where we will store the result of our additions. If the value passed to atoi is not an ascii representation of an integer our function will return zero instead. When all arguments have been converted and added together we will print out the result and call our quit function.
我们的程序首先使用 POP 指令从堆栈中获取传递的参数数量。此值存储在 ECX （最初称为 counter register） 中。然后，它将从包含程序名称的堆栈中弹出下一个值，并将其从 ECX 中存储的参数数量中删除。然后，它将遍历其余的参数，将每个参数从堆栈中弹出并执行我们的加法逻辑。正如我们所知，通过命令行传递的参数被我们的程序以字符串形式接收。在我们将参数添加在一起之前，我们需要将它们转换为整数，否则我们的结果将不正确。我们通过调用 Ascii to Integer 函数 （atoi） 来实现这一点。此函数会将 ASCII 值转换为整数，并将结果放入 EAX 中。然后，我们可以将此值添加到 EDX（最初称为数据寄存器）中，我们将在其中存储添加的结果。如果传递给 atoi 的值不是整数的 ASCII 表示，我们的函数将返回零。当所有参数都被转换并加在一起时，我们将打印出结果并调用我们的 quit 函数。

How does the atoi function work
atoi 函数是如何工作的

Converting an ascii string into an integer value is not a trivial task. We know how to convert an integer to an ascii string so the process should essentially work in reverse. Firstly we take the address of the string and move it into ESI (originally known as the source register). We will then move along the string byte by byte (think of each byte as being a single digit or decimal placeholder). For each digit we will check if it's value is between 48-57 (ascii values for the digits 0-9).
将 ASCII 字符串转换为整数值并非易事。我们知道如何将整数转换为 ASCII 字符串，因此该过程基本上应该是相反的。首先，我们获取字符串的地址并将其移动到 ESI （最初称为 source register）。然后，我们将逐字节地沿着字符串移动（将每个字节视为单个数字或小数点占位符）。对于每个数字，我们将检查它的值是否在 48-57 之间（数字 0-9 的 ASCII 值）。

Once we have performed this check and determined that the byte can be converted to an integer we will perform the following logic. We will subtract 48 from the value – converting the ascii value to it's decimal equivalent. We will then add this value to EAX (the general purpose register that will store our result). We will then multiple EAX by 10 as each byte represents a decimal placeholder and continue the loop.
一旦我们执行了此检查并确定字节可以转换为整数，我们将执行以下逻辑。我们将从值中减去 48 – 将 ascii 值转换为它的十进制等效值。然后我们将此值添加到 EAX （将存储结果的通用寄存器）。然后，我们将 EAX 乘以 10，因为每个字节代表一个小数点占位符并继续循环。

When all bytes have been converted we need to do one last thing before we return the result. The last digit of any number represents a single unit (not a multiple of 10) so we have multiplied our result one too many times. We simple divide it by 10 once to correct this and then return. If no integer arguments were pass however, we skip this divide instruction.
当所有字节都被转换后，我们需要在返回结果之前做最后一件事。任何数字的最后一位数字都代表一个单位（不是 10 的倍数），因此我们将结果乘以太多次。我们简单地将其除以 10 一次来纠正这个问题，然后返回。但是，如果未传递整数参数，则跳过此 divide 指令。

What is the BL register
什么是提单登记册

You may have noticed that the atoi function references the BL register. So far in these tutorials we have been exclusively using 32bit registers. These 32bit general purpose registers contain segments of memory that can also be referenced. These segments are available in 16bits and 8bits. We wanted a single byte (8bits) because a byte is the size of memory that is required to store a single ascii character. If we used a larger memory size we would have copied 8bits of data into 32bits of space leaving us with 'rubbish' bits - because only the first 8bits would be meaningful for our calculation.
您可能已经注意到 atoi 函数引用了 BL 寄存器。到目前为止，在这些教程中，我们一直只使用 32 位寄存器。这些 32 位通用寄存器包含也可以引用的内存段。这些段有 16 位和 8 位两种版本。我们想要一个字节 （8bits），因为一个字节是存储单个 ASCII 字符所需的内存大小。如果我们使用更大的内存大小，我们会将 8 位数据复制到 32 位空间中，留下“垃圾”位 - 因为只有前 8 位对我们的计算有意义。

The EBX register is 32bits. EBX's 16 bit segment is referenced as BX. BX contains the 8bit segments BL and BH (Lower and Higher bits). We wanted the first 8bits (lower bits) of EBX and so we referenced that storage area using BL.
EBX 寄存器为 32 位。EBX 的 16 位段称为 BX。BX 包含 8 位段 BL 和 BH（低位和高位）。我们想要 EBX 的前 8 位（较低位），因此我们使用 BL 引用该存储区域。

Almost every assembly language tutorial begins with a history of the registers, their names and their sizes. These tutorials however were written to provide a foundation in NASM by first writing code and then understanding the theory. The full story about the size of registers, their history and importance are beyond the scope of this tutorial but we will return to that story in later tutorials.
几乎每个汇编语言教程都以寄存器的历史、它们的名称和大小开始。但是，编写这些教程是为了提供 NASM 的基础，首先编写代码，然后理解理论。有关 register 的大小、它们的历史和重要性的完整故事超出了本教程的范围，但我们将在后面的教程中返回该故事。

Note: Only the new function in this file 'atoi' is shown below.
注意：下面仅显示此文件中的 new function 'atoi'。

Namespace is a necessary construct in any software project that involves a codebase that is larger than a few simple functions. Namespace provides scope to your identifiers and allows you to reuse naming conventions to make your code more readable and maintainable. In assembly language where subroutines are identified by global labels, namespace can be achieved by using local labels.
Namespace 是任何涉及比几个简单函数更大的代码库的软件项目中的必要结构。Namespace 为您的标识符提供范围，并允许您重用命名约定，使您的代码更具可读性和可维护性。在子例程由全局标签标识的汇编语言中，可以使用局部标签来实现命名空间。

Up until the last few tutorials we have been using global labels exclusively. This means that blocks of logic that essentially perform the same task needed a label with a unique identifier. A good example would be our "finished" labels. These were global in scope meaning when we needed to break out of a loop in one function we could jump to a "finished" label. But if we needed to break out of a loop in a different function we would need to name this same task something else maybe calling it "done" or "continue". Being able to reuse the label "finished" would mean that someone reading the code would know that these blocks of logic perform almost the same task.
在最近几个教程之前，我们一直只使用全局标签。这意味着本质上执行相同任务的 logic blocks 需要一个具有唯一标识符的 label。一个很好的例子是我们的 “finished” 标签。这些是全局范围的，这意味着当我们需要一个函数跳出一个循环时，我们可以跳转到“finished”标签。但是，如果我们需要在不同的函数中跳出一个循环，我们需要将同一个任务命名为其他名称，可能将其命名为 “done” 或 “continue”。能够重用 “finished” 标签意味着阅读代码的人会知道这些 logic blocks 执行几乎相同的任务。

Local labels are prepended with a "." at the beginning of their name for example ".finished". You may have noticed them appearing as our code base in functions.asm grew. A local label is given the namespace of the first global label above it. You can jump to a local label by using the JMP instruction and the compiler will calculate which local label you are referencing by determining in what scope (based on the above global labels) the instruction was called.
本地标签在其名称的开头加上 “..”，例如 “.finished”。你可能已经注意到，它们随着 functions.asm 中的代码库的增长而出现。为本地标签提供其上方第一个全局标签的命名空间。您可以使用 JMP 指令跳转到本地标签，编译器将通过确定调用该指令的范围（基于上述全局标签）来计算您引用的局部标签。

Note: The file functions.asm was modified adding namespaces in all the subroutines. This is particularly important in the "slen" subroutine which contains a "finished" global label.
注意：修改了 functions.asm 文件，在所有子例程中添加了命名空间。这在包含 “finished” 全局标签的 “slen” 子例程中尤为重要。

Firstly, some background 首先，一些背景

FizzBuzz is group word game played in schools to teach children division. Players take turns to count aloud integers from 1 to 100 replacing any number divisible by 3 with the word "fizz" and any number divisible by 5 with the word "buzz". Numbers that are both divisible by 3 and 5 are replaced by the word "fizzbuzz". This children's game has also become a defacto interview screening question for computer programming jobs as it's thought to easily discover candidates that can't construct a simple logic gate.
FizzBuzz 是在学校玩的集体文字游戏，用于教孩子们除法。玩家轮流大声数出从 1 到 100 的整数，将任何可被 3 整除的数字替换为单词“fizz”，将任何可被 5 整除的数字替换为单词“buzz”。都可以被 3 和 5 整除的数字被单词 “fizzbuzz” 替换。这款儿童游戏也已成为计算机编程工作事实上的面试筛选问题，因为它被认为可以轻松发现无法构建简单逻辑门的候选人。

Writing our program 编写我们的程序

There are a number of code solutions to this simple game and some languages offer very trivial and elegant solutions. Depending on how you choose to solve it, the solution almost always involves an if statement and possibly an else statement depending whether you choose to exploit the mathematical property that anything divisible by 5 & 3 would also be divisible by 3 * 5. Being that this is an assembly language tutorial we will provide a solution that involves a structure of two cascading if statements to print the words "fizz" and/or "buzz" and an else statement in case these fail, to print the integer as an ascii value. Each iteration of our loop will then print a line feed. Once we reach 100 we call our program exit function.
这个简单的游戏有许多代码解决方案，有些语言提供了非常简单和优雅的解决方案。根据你选择如何解决它，解决方案几乎总是涉及一个if语句和一个可能的else语句，这取决于你是否选择利用数学特性，即任何能被5和3整除的东西也会被3 * 5整除。由于这是一个汇编语言教程，我们将提供一个解决方案，该解决方案涉及两个级联 if 语句的结构，用于打印单词 “fizz” 和/或 “buzz” 和一个 else 语句，如果这些语句失败，将整数打印为 ASCII 值。然后，循环的每次迭代都会打印一个换行符。一旦我们达到 100，我们调用我们的程序 exit 函数。

Firstly, some background 首先，一些背景

The EXEC family of functions replace the currently running process with a new process, that executes the command you specified when calling it. We will be using the SYS_EXECVE function in this lesson to replace our program's running process with a new process that will execute the linux program /bin/echo to print out “Hello World!”.
EXEC 系列函数将当前正在运行的进程替换为新进程，该进程将执行您在调用该进程时指定的命令。在本课中，我们将使用 SYS_EXECVE 函数将程序的运行进程替换为新进程，该进程将执行 linux 程序 /bin/echo 以打印出 “Hello World！”。

Naming convention 命名约定

The naming convention used for this family of functions is exec (execute) followed by one or more of the following letters.
用于此函数系列的命名约定是 exec （execute），后跟以下一个或多个字母。

• e - An array of pointers to environment variables is explicitly passed to the new process image.
  e - 将指向环境变量的指针数组显式传递给新的进程映像。
• l - Command-line arguments are passed individually to the function.
  l - 命令行参数单独传递给函数。
• p - Uses the PATH environment variable to find the file named in the path argument to be executed.
  p - 使用 PATH 环境变量查找要执行的 path 参数中命名的文件。
• v - Command-line arguments are passed to the function as an array of pointers.
  v - 命令行参数作为指针数组传递给函数。

Writing our program 编写我们的程序

The V & E at the end of our function name means we will need to pass our arguments in the following format: The first argument is a string containing the command to execute, then an array of arguments to pass to that command and then another array of environment variables that the new process will use. As we are calling a simple command we won't pass any special environment variables to the new process and instead will pass 0h (null).
我们的函数名称末尾的V和E意味着我们需要按照以下格式传递我们的参数：第一个参数是一个包含要执行的命令的字符串，然后是一个要传递给该命令的参数数组，然后是新进程将使用的另一个环境变量数组。由于我们调用的是一个简单的命令，因此我们不会将任何特殊的环境变量传递给新进程，而是传递 0h （null）。

Both the command arguments and the environment arguments need to be passed as an array of pointers (addresses to memory). That's why we define our strings first and then define a simple null-terminated struct (array) of the variables names. This is then passed to SYS_EXECVE. We call the function and the process is replaced by our command and output is returned to the terminal.
command 参数和 environment 参数都需要作为指针数组（指向内存的地址）传递。这就是为什么我们首先定义字符串，然后定义变量名称的简单以 null 结尾的结构体（数组）。然后将其传递给 SYS_EXECVE。我们调用函数，进程被我们的命令替换，输出返回到终端。

Note: Here are a couple other commands to try.
注意：以下是可以尝试的其他几个命令。

Firstly, some background 首先，一些背景

In this lesson we will use SYS_FORK to create a new process that duplicates our current process. SYS_FORK takes no arguments - you just call fork and the new process is created. Both processes run concurrently. We can test the return value (in eax) to test whether we are currently in the parent or child process. The parent process returns a non-negative, non-zero integer. In the child process EAX is zero. This can be used to branch your logic between the parent and child.
在本课中，我们将使用 SYS_FORK 创建一个复制当前流程的新流程。SYS_FORK 不接受任何参数 - 您只需调用 fork 并创建新进程。两个进程同时运行。我们可以测试返回值（以 eax 为单位）以测试我们当前是在父进程还是子进程中。父进程返回一个非负、非零的整数。在子进程中，EAX 为零。这可用于在 parent 和 child 之间对 logic 进行分支。

In our program we exploit this fact to print out different messages in each process.
在我们的程序中，我们利用这一事实在每个进程中打印出不同的消息。

Note: Each process is responsible for safely exiting.
注意：每个进程都负责安全退出。

Generating a unix timestamp in NASM is easy with the SYS_TIME function of the linux kernel. Simply pass OPCODE 13 to the kernel with no arguments and you are returned the Unix Epoch in the EAX register.
使用 linux 内核的 SYS_TIME 功能，在 NASM 中生成 unix 时间戳很容易。只需将 OPCODE 13 不带参数地传递给内核，即可在 EAX 寄存器中返回 Unix Epoch。

That is the number of seconds that have elapsed since January 1st 1970 UTC.
这是自 1970 年 1 月 1 日 UTC 以来经过的秒数。

Firstly, some background 首先，一些背景

File Handling in Linux is achieved through a small number of system calls related to creating, updating and deleting files. These functions require a file descriptor which is a unique, non-negative integer that identifies the file on the system.
Linux 中的文件处理是通过与创建、更新和删除文件相关的少量系统调用来实现的。这些函数需要一个文件描述符，它是一个唯一的非负整数，用于标识系统上的文件。

Writing our program 编写我们的程序

We begin the tutorial by creating a file using sys_creat. We will then build upon our program in each of the following file handling lessons, adding code as we go. Eventually we will have a full program that can create, update, open, close and delete files.
在本教程中，我们首先使用 sys_creat 创建一个文件。然后，我们将在以下每个文件处理课程中以我们的程序为基础，随时添加代码。最终，我们将拥有一个完整的程序，可以创建、更新、打开、关闭和删除文件。

sys_creat expects 2 arguments - the file permissions in ECX and the filename in EBX. The sys_creat opcode is then loaded into EAX and the kernel is called to create the file. The file descriptor of the created file is returned in EAX. This file descriptor can then be used for all other file handling functions.
sys_creat需要 2 个参数 - ECX 中的文件权限和 EBX 中的文件名。然后将 sys_creat 操作码加载到 EAX 中，并调用内核来创建文件。创建的文件描述符在 EAX 中返回。然后，此文件描述符可用于所有其他文件处理功能。

Note: The file 'readme.txt' will now have been created in the folder.
注意：现在，文件 'readme.txt' 将在文件夹中创建。

Building upon the previous lesson we will now use sys_write to write content to a newly created file.
在上一课的基础上，我们现在将使用 sys_write 将内容写入新创建的文件。

sys_write expects 3 arguments - the number of bytes to write in EDX, the contents string to write in ECX and the file descriptor in EBX. The sys_write opcode is then loaded into EAX and the kernel is called to write the content to the file. In this lesson we will first call sys_creat to get a file descriptor which we will then load into EBX.
sys_write需要 3 个参数 - 要在 EDX 中写入的字节数、要在 ECX 中写入的内容字符串以及 EBX 中的文件描述符。然后将 sys_write 操作码加载到 EAX 中，并调用内核将内容写入文件。在本课中，我们将首先调用 sys_creat 来获取文件描述符，然后将其加载到 EBX 中。

Note: Open the newly created file 'readme.txt' in this folder and you will see the content 'Hello world!'.
注意：在此文件夹中打开新创建的文件 'readme.txt' ，您将看到内容 'Hello world！'

Building upon the previous lesson we will now use sys_open to obtain the file descriptor of the newly created file. This file descriptor can then be used for all other file handling functions.
在上一课的基础上，我们现在使用 sys_open 来获取新创建的文件的文件描述符。然后，此文件描述符可用于所有其他文件处理功能。

sys_open expects 2 arguments - the access mode (table below) in ECX and the filename in EBX. The sys_open opcode is then loaded into EAX and the kernel is called to open the file and return the file descriptor.
sys_open需要 2 个参数 - ECX 中的访问模式（下表）和 EBX 中的文件名。然后将sys_open操作码加载到 EAX 中，并调用内核以打开文件并返回文件描述符。

sys_open additionally accepts zero or more file creation flags and file status flags in EDX. Click here for more information about the access mode, file creation flags and file status flags.
sys_open 还接受 EDX 中的零个或多个文件创建标志和文件状态标志。单击此处了解有关访问模式、文件创建标志和文件状态标志的更多信息。

Note: sys_open returns the file descriptor in EAX. On linux this will be a unique, non-negative integer which we will print using our integer printing function.
注意：sys_open 返回 EAX 中的文件描述符。在 linux 上，这将是一个唯一的非负整数，我们将使用整数打印函数打印它。

Building upon the previous lesson we will now use sys_read to read the content of a newly created and opened file. We will store this string in a variable.
在上一课的基础上，我们现在将使用 sys_read 来读取新创建和打开的文件的内容。我们将此字符串存储在变量中。

sys_read expects 3 arguments - the number of bytes to read in EDX, the memory address of our variable in ECX and the file descriptor in EBX. We will use the previous lessons sys_open code to obtain the file descriptor which we will then load into EBX. The sys_read opcode is then loaded into EAX and the kernel is called to read the file contents into our variable and is then printed to the screen.
sys_read需要 3 个参数 - EDX 中要读取的字节数、ECX 中变量的内存地址以及 EBX 中的文件描述符。我们将使用前面的课程sys_open代码来获取文件描述符，然后将其加载到 EBX 中。然后将 sys_read 操作码加载到 EAX 中，并调用内核将文件内容读入我们的变量，然后打印到屏幕上。

Note: We will reserve 255 bytes in the .bss section to store the contents of the file. See Lesson 9 for more information on the .bss section.
注意：我们将在 .bss 部分保留 255 字节来存储文件的内容。有关 .bss 部分的更多信息，请参阅第 9 课。

Building upon the previous lesson we will now use sys_close to properly close an open file.
在上一课的基础上，我们现在将使用 sys_close 正确关闭打开的文件。

sys_close expects 1 argument - the file descriptor in EBX. We will use the previous lessons code to obtain the file descriptor which we will then load into EBX. The sys_close opcode is then loaded into EAX and the kernel is called to close the file and remove the active file descriptor.
sys_close需要 1 个参数 - EBX 中的文件描述符。我们将使用前面的课程代码来获取文件描述符，然后将其加载到 EBX 中。然后将 sys_close 操作码加载到 EAX 中，并调用内核以关闭文件并删除活动文件描述符。