Compiling an assembly program with NASM can be done on Linux or Windows as NASM is available for both platforms. The Netwide Assembler or the NASM is a popular assembler which is used for programming assembly code with x86 Intel processor architecture. Unlike high level programming languages, an assembly language code comprises only of mnemonics and symbols. It is possible to create an executable from NASM code to run on Linux or Windows. Running the executable on Linux and Windows requires a simple command line procedure which is specific to each operating system after compiling an assembly program with the NASM on Linux or Windows.
Netwide Assembler (NASM) is an assembler and dissembler for the Intel x86 architecture and is commonly used to create 16-bit, 32-bit (IA-32) and 64-bit (x86-64) programs. It is available on multiple operating systems like Linux or Windows, for example.
An assemble will turn your low-level coding, using mnemonics, into machine language that can be understood by the processor.
This article will not teach you to program with NASM, but to create an executable for Linux and Windows from NASM source code.
Step 1. Create a source file
You can use any text editor to create your source file for NASM such as Gedit, KWrite, or XEmacs.
When you save your file, give it the extension .asm
Step 2. Assemble the source file
For this step, you will need NASM software installed on your machine. If you're running Debian or Ubuntu, simply type the command:
sudo apt-get install nasm
If you have another Linux distribution, you must use your distribution's package manager (eg Urpmi, Yum, Emerge) or download NASM from the official site.
Use the following command line to assemble your source file:
nasm -f elf test.asm
In the example, the saved .asm file is called test.asm
This will create a file named test.o in the current directory. Note: This file is not executable - it is still an object file.
Step 3. Creating the executable
Now that we have our object file named test.o we must create our executable.
Two cases are presented here:
Your program begins with a procedure called "_start". This means that your program has its own point of entry without the use of the main function. However, you'll need to use the "l" to create your executable:
ld test.o -o test
Your program begins with a procedure called "main". You will need to use gcc to create your executable:
gcc test.o -o test
Our executable is created, it is tested and is in the current directory.
Step 4. Program Execution
To run the program called "test", just type this command:
. / test
Under the windows the convention is not the same. The main function is not available under Windows and must be replaced by WinMain.
If your entry point is "_start" or "main", it should be changed to "_WinMain @ 16" and change the "ret" at the end of the procedure to "ret 16":
mov eax, 0
Leave all options selected by default and then wait for it to install.
Now we'll insert NASM in the development environment MinGW:
Unpack the NASM archive.
You should get a folder containing, among other things, a file named nasm.exe
Copy this file into the directory C: \ MinGW \ bin
Step 2. Create a source file
Like Linux, there is no need to use a specific publisher to create a source file for NASM. You can use Notepad but beware - it tends to add the .txt extension to files it creates. To remove any ambiguity, it is recommend that you view the extensions of your files.
In any case, avoid word processors such as Word or WordPad.
If you wish, you can also use an editor that uses NASM syntax, such NasmEdit IDE (free).
Make sure your save your source file with the .asm extension.
Step 3. Assemble the source file
Open the Command window by going to Start > Run and typing cmd.exe
Using the command "cd", go to the folder containing your source file
Once you are in this directory, assemble your source file (test.asm) with this command:
nasm -f win32 test.asm -o test.o
You have now created an object file. The next step will turn it into an executable file.
Step 4. Creation and execution of the program
From your Command window, type the final command to create the executable:
ld test.o -o test.exe
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