Getting Started with MASM and Visual Studio 2022

Updated 3/23/2022

This tutorial assumes that you are using either the 7th or 8th Edition of Assembly Language for x86 Processors, and you are using Visual Studio 2022.

Before starting the tutorials listed below, please visit our GitHub project page (surferkip/asmbook) to download the following files:

  • - code examples and required libraries
  • - sample 32-bit Visual Studio 2022 project, configured for assembly language
  • - sample 64-bit Visual Studio 2022 project, configured for assembly language


Found an error in this document? Please email the author.

Required Setup for 32-bit Applications

After you have downloaded and installed the VS 2022 Community Edition, you may need to enable Visual C++ Desktop development. First, let's see if it has already been installed (as often happens in college computer labs). When you start Visual Studio, click the "Create a new project" panel on the startup window:

Next, in the Create a new project dialog window, look for Console App project type with a C++ button in the list of Recent project templates.

If you do not see C++ in the list, close Visual Studio and run a separate program named the Visual Studio Installer. If your computer is in a college laboratory, your account may not have sufficient privileges to run this program, so you can ask your lab supervisor to do it for you.

The Visual Studio Installer

If you run the VS installer, select the Desktop development with C++ button in the installer window, look at the Summary list on the right side to verify that VC++ is selected, and click the Modify button in the lower right corner of the window.

The Visual C++ language includes the Microsoft Assembler (MASM). To verify that MASM is installed, open a Windows Explorer window and look for the file named ml.exe in the Visual Studio installation directory, such as C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.nn.nnnn\bin\HostX64\x86. (The "n" characters above indicate digits in the version number of your current VS installation.)

The Book's Example Programs

At the top of this document, we explained how to download the file named and extract it into the C:\Irvine folder. Unless you have some objection to using that location, do not alter the path. (Note to lab administrators: you can designate c:\Irvine directory as read-only.).

The folllowing files should appear in the c:\Irvine directory:

Filename Description
b16.asm, b32.asm Blank templates for 16-bit and 32-bit assembly language source files Include file for writing Windows applications Include file used with the Irvine16 link library (16-bit applications)
Irvine16.lib 16-bit link function library used with this book Include file used with the Irvine32 link library (32-bit applications)
Irvine32.lib Irvine's 32-bit link library
Kernel32.lib 32-bit link library for Windows API
Link16.exe 16-bit Microsoft linker Irvine's macro include file (see Chapter 10) Small-sized include file containing MS-Windows definitions, used by
User32.lib MS-Windows basic I/O link library Keyboard code definitions file, used by

A subdirectory named Examples will contain all the example programs shown in the book, source code for the book's 16-, 32-, and 64-bit libraries, and two sample projects for earlier versions of Visual Studio.

Configuring Visual Studio

You can open Visual Studio without opening or creating a project. In the initial splash screen, select Continue without code just below the Create a new project button.

Select the C++ Configuration

Visual Studio supports multiple programming languages and application types. The C++ programming language configuration most closely matches that of assembly language programming, so we suggest the following steps:
  1. Select Tools >> Import and Export Settings from the menu
  2. Select the "Import selected environment settings" radio button
  3. Select the "No, just import..." radio button
  4. Select "Visual C++" from the Default Settings List and click the Next button
  5. Click the Finish button, then click the Close button
  6. Notice the tabs on the left and right sides of the Visual Studio workspace. Close the Server Explorer and Toolbox tabs. (Optionally, you can use the mouse to drag the Solution Explorer tool window to either side of the workspace.) If you should ever accidentally close a window in the future, you can bring it back: select View from the menu, and locate the name of the windows from the View menu list.

Optional Step: Set the tab indent size

Start Visual Studio and select Options from the Tools menu. Select and expand the Text Editor item, select All Languages, and select Tabs. Optionally, you may want to select the Insert spaces radio button:

I prefer to set the Tab Size and Indent Size values to 5, and Indenting to none.

Tutorial: Building and running a 32-bit program

Now you're ready to open and build your first 32-bit project.

Opening a Project

Visual Studio requires assembly language source files to belong to a project, which is a kind of container. A project holds configuration information such as the locations of the assembler, linker, and required libraries. A project has its own folder, and it holds the names and locations of all files belonging to it.

Following the instructions at the top of this web page, download the file and unzip it into your working directory. It contains a sample asm test file named AddTwo.asm.

Follow these steps:

  1. Start Visual Studio.
  2. Open our sample Visual Studio project file by selecting File/Open/Project from the Visual Studio menu.
  3. Navigate to your working folder where you unzipped our project file, and select the file named Project.sln.
  4. Once the project has been opened, you will see the project name in Visual Studio's Solution Explorer window. You should also see an assembly language source file in the project named AddTwo.asm. Double-click the file name to open it in the editor.

You should see the following program in the editor window:

; AddTwo.asm - adds two 32-bit integers.
; Chapter 3 example

.model flat,stdcall
.stack 4096
ExitProcess proto,dwExitCode:dword

main proc
	mov	eax,5				
	add	eax,6				

	invoke ExitProcess,0
main endp
end main

In the future, you can use this file as a starting point to create new programs by copying it and renaming the copy in the Solution Explorer window.

Adding a File to a Project: If you need to add an .asm file to an open project, do the following: (1) Right-click the project name in the Visual Studio window, select Add, select Existing Item. (2) In the Add Existing Item dialog window, browse to the location of the file you want to add, select the filename, and click the Add button to close the dialog window.

Build the Program

Now you will build (assemble and link) the sample program. Select Build Project from the Build menu. In the Output window for Visual Studio at the bottom of the screen, you should see messages similar to the following, indicating the build result:

Build started...
1>------ Build started: Project: Project, Configuration: Debug Win32 ------
1>Assembling AddTwo.asm...
1>Project.vcxproj -> ...\Project32_VS2022\Debug\Project.exe
========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========
(The ... above represents a machine-specific path.)

If you do not see these messages, the project has probably not been modified since it was last built. No problem--just select Rebuild Project from the Build menu.

Run the Program in Debug Mode

The easiest way to run your first program is to use the debugger. First, you must set a breakpoint. When you set a breakpoint in a program, you can use the debugger to execute the program a full speed (more or less) until it reaches the breakpoint. At that point, the debugger drops into single-step mode. Here's how to do it:

  1. Make sure the ASM source code file is open in the editor window.
  2. Click the mouse along the border to the left of the mov eax,5 statement. A large red dot should appear in the margin.
  3. Select Start Debugging from the Debug menu. The program should run and pause on the line with the breakpoint. (Optionally, you can close the Diagnostic Tools, Autos, and Call Stack windows.)
  4. Don't be surprised to see a new window suddently appear, named the "Console window", with a plain black background. It's the window that displays your program's output while you're stepping through the code.
  5. Press the F10 key (called Step Over) to execute the current statement. Continue pressing F10 until the program is about to execute the invoke statement.
  6. Press F10 one more time to end the program.

You can remove a breakpoint by clicking its dot with the mouse. Take a few minutes to experiment with the Debug menu commands. Set more breakpoints and run the program again.

Here's what your program will look like when paused at the breakpoint:

You may also notice the following message in the Console window when your program finishes. It offers you the option of letting Visual Studio close the window automatically when your programs finish:

Running a program from the Command Prompt

When you assembled and linked the sample project, a file named Project.exe was created inside the project's \Debug folder. This file executes when you run the project. You can execute any exe file by double-clicking its name inside Windows Explorer, but it will often just flash on the screen and disappear. That is because Windows Explorer does not pause the display before closing the command window. On the other hand, you can open a Command prompt window, move to the Debug directory, and run Project.exe by typing "Project" (without the quotes). You will need to do some reading on Windows shell commands if you plan to use the command line.

Final note: To remove a source file from the Visual Studio window, right-click its filename and select Remove. The file will not be deleted from the file system. On the other hand, if you want to delete the file, select it and press the Del key.


Soon you will want to display CPU registers when debugging your programs. Here's how to make them visible: First, under the Tools >> Options menu, select Debbuging in the left panel, and select Enable address-level debugging. Next, set a breakpoint in your source code on an executable statement, run your program in Debug mode, select Windows from the Debug menu, and then select Registers from the drop-down list.

The Registers window may appear docked to the Visual Studio workspace, but you may find it helpful to let the window float so you can move it anywhere on your computer desktop. You can grab the window header with the mouse and pull it to a new location. You will also want to display the CPU flags inside the Registers window. To do that, right click inside the Registers window and check the word Flags from the popup menu. Here's what it looks like:

You can interrupt a debugging session at any time by selecting Stop Debugging from the Debug menu. You can do the same by clicking the red square button on the toolbar. To remove a breakpoint from a program, click its red dot to make it disappear.

A reminder, you might want to review our tutorial: Using the Visual Studio debugger

Building and Running Other Programs

Suppose you want to run another example program, or possibly create your own program. You can remove the existing assembly language file from the Solution Explorer window and insert a new .asm file into the project.

  • To remove a program from a project without deleting the file, right-click its name in the Solution Explorer window. In the context menu, select Remove. If you change your mind and decide to add it back to the project, right-click in the same window, select Add, select Existing item, and select the file you want to add.

Adding a File to a Project

An easy way to add an assembly language source file to an open project is to drag its filename with the mouse from a Windows Explorer window onto the name of your project in the Solution Explorer window. The physical file will not be copied--the project only holds a reference to the file's location. Try this now:

  1. Remove the AddTwo.asm file from your project.
  2. Add a reference to the file Examples\ch03\AddTwoSum.asm to the project.
  3. Build and run the project.

Copying a Source File

One way to make a copy of an existing source code file is to use Windows Explorer to copy the file into your project directory. Then, right-click the project name in Solution Explorer, select Add, select Existing Item, and select the filename.

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Tutorial: Building and running a 64-bit program

In this tutorial, we will show you how to assemble, link, and run a sample 64-bit program. We assume you have already completed our tutorial entitled Building a 32-Bit Assembly Language Program.

Do the following steps, in order:

  1. Following the instructions at the top of this web page, download the file and unzip it into your working directory.
  2. In Visual Studio 2022, select Open Project from the File menu, navigate to the Project64_VS2022 folder, and select the file named Project.sln.
  3. You are about to add an existing source code file to the project. To do that, right-click on Project in the Solution Explorer window, select Add,  select Existing Item, navigate to the book's Examples\ch03\64 bit" folder, select AddTwoSum_64.asm, and click the Add button to close the dialog window.
  4. Open the AddTwoSum_64.asm file for editing by double-clicking its filename in the Solution Explorer window.

You should see the following program in the editor window:

; AddTwoSum_64.asm - Chapter 3 example.

ExitProcess proto

sum qword 0

main proc
   mov  rax,5
   add  rax,6
   mov  sum,rax

   mov  ecx,0
   call ExitProcess

main endp
(Notice that the program's entry point is the main procedure. If you wish to use a different name for your startup procedure in your own programs, you can modify this option by selecting Properties from the Project menu, and then selecting Linker / Advanced / Entry Point.)

Build the Program

Select Build Project from the Build menu. You should see text written to Visual Studio's output window like the following:
1>------ Build started: Project: Project, Configuration: Debug x64 ------
1>  Assembling AddTwoSum_64.asm...
1>  Project64.vcxproj -> ...\Project64_VS2022\x64\Debug\Project.exe
========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========
If you do not see these messages, the project has probably not been modified since it was last built. No problem--just select Rebuild Project from the Build menu.

You use the same Visual Studio commands to run and debug 64-bit programs as you would for 32-bit programs.

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Building 16-bit programs (Chapters 14-17)

Only Chapters 14 through 17 require you to build 16-bit applications. Except for a few exceptions, which are noted in the book, your 16-bit applications will run under the 32-bit versions of Windows (Windows XP, Windows Vista, Windows 7).

If you're interested in running 16-bit programs under 64-bit Windows, you will need to enable a feature named NTVDM.) Click here to read a web site with instructions on how to do this. Another alternative you may wish to explore is to install a virtual machine (using a free program named VirtualBox from Oracle) and install 32-bit Windows on the virtual machine.

The book's example programs in Chapters 1-13 have been successfully tested in 32-bit Windows 7,8, and 10. On the other hand, many programs in Chapters 14-17 will not run in any Microsoft OS later than Windows 98, because they rely on direct access to hardware and system memory. You cannot directly run 16-bit applications in any 64-bit version of Windows.

If you plan to build 16-bit applications, you need to add two new commands to the Visual Studio Tools menu. To add a command, select External Tools from the Tools menu. The following dialog will appear, although many of the items in your list on the left side will be missing. Download the batch file here (rename the .txt extension to .bat after downloading): make16_vs2022.txt.


Step 1: Create the Build 16-bit ASM Command

Click the Add button and fill in the Title, Command, Arguments, and Initial directory fields as shown in the screen snapshot. If you click the buttons with arrows on the right side of the Arguments and Initial directory fields, a convenient list appears. You can select an item without having to worry about spelling:

Click the Apply button to save the command.


Step 2: Create the Run 16-bit ASM Command

Click the Add button again, and create a new command named Run 16-bit ASM:

Uncheck the "Close on exit" option and click the OK button to save the command and close the External Tools dialog.

Testing Your new 16-Bit Commands

To test your new 16-bit commands, close any Visual Studio project that happens to be open. Then, select File | Open | File from the menu and choose the file named 16-bit.asm from the ch03 folder in the book's example programs. Select Build 16-bit ASM from the Tools menu. The following command window should appear, showing the successful execution of the assembler and linker, followed by a listing of all files related to this program:

Press a key to close the window. Next, you will run the program. Select Run 16-bit ASM from the Tools menu. The following window will appear, although the contents of all registers except EAX will be different:

Press a key to close the window.

You have completed the setup for building and running 16-bit assembly language programs.

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Syntax highlighting in your source code

When a text editor uses syntax highlighting, language keywords, strings, and other elements appear in different colors. Visual Studio highlights MASM reserved words and strings, as shown in the following example:

This won't happen automatically, but you can create a syntax definition file named Usertype.dat that contains MASM keywords. Then when Visual Studio starts, it reads the syntax file and highlights MASM keywords.

If you decide to use Visual Studio's built-in MASM syntax highlighter, here are the required steps to set it up:

1) Download this Usertype.dat file (enclosed in a ZIP file) given here to a folder in which you have read/write permissions. Extract it from the zip archive.

2) Close Visual Studio.

3) Copy Usertype.dat to the C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\IDE folder.

Windows will display a confirmation dialog before copying the file.

4) Open Visual Studio, select Options from the Tools menu, select Text Editor, and select File Extension. On the right side of the dialog (shown below), enter asm as the extension, select Microsoft Visual C++ from the Editor list, and click the Add button. Click the OK button to save your changes.

Open your project and display an ASM file. You should see syntax highlighting in the editor. There is a glitch in the highlighting--assembly language comment line starts start with a semicolon, which C++ doesn't recognize. But this is a simple workaround: add an extra // right after the semicolon, like this, which will cause the comments to appear in their usual green color:

;// AddTwo.asm - adds two 32-bit integers.
;// Chapter 3 example
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Was your program's EXE file blocked by an Antivirus scanner?

Antivirus scanner software has improved greatly in recent years, and so have the number of viruses (one website reports 50,000 at present). Because of this, your computer's antivirus scanner may report a false positive when you build your program, and refuse to let you run it. There are a few workarounds: (1) You can add your project's bin/debug folder into an exclusion list in your antivirus configuration. This is my preferred approach, and it nearly always works. (2) You can suspend your realtime antivirus scanner software, but this will leave you open to malware for a short time. If you choose this option, be sure to temporarily disconnect your computer from the Internet.

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Tip: If the Solution Explorer window is not visible, select Solution Explorer from the View menu. Also, if you do not see main.asm in the Solution Explorer window, it might be hidden behind another window. To bring it to the front, click the Solution Explorer tab from the tabs shown along the bottom of the window.