wcsanders1 / AssemblyLanguageExercises

Exercises from Assembly Language for x86 Processors, by Kip Irvine

Assembly Language in Visual Studio

Introduction

This presentation will demonstrate how to set up a project in Visual Studio to write, assemble, run, and debug assmebly code using the Microsoft Assembler (MASM), which is included with Visual Studio. This is not a tutorial on assembly, and I am not qualified to give such a tutorial. Rather, the purpose of this presentation is to explore a capability of Visual Studio that most users may never encounter, and to do some low-level programming.

What is assembly language?

Assembly language is a low-level programming language with a nearly one-to-one correspondence with the computer's machine code instructions. It is mostly a set of mnemonic codes referring to machine codes. Assembly language is converted into machine code by an assembler, whereas higher-level languages like C# are compiled by a compiler, which may make decisions on its own based on the entirety of the program.

Setting up a Visual Studio project to write assembly

• Install an assembly language plugin to add intellisence and syntax highlighting. I used AsmDude, and there are others.
• Create a new empty C++ project (don't worry, this isn't going to be just a C++ program with inline assembly)
• Right-click on the project, go to Build Dependencies -> Build Customizations and select masm
• Add a file to the project with the .asm extension
• To make assembly programming easier, download the library files from http://asmirvine.com/gettingStartedVS2019/index.htm. To use these libraries in your programs:
  • right click the project in Visual Studio, go to Microsoft Macro Assembler -> General and add the directory to those library files to Include Paths
  • go to Linker -> General and add that directory to Additional Library Directories
  • go to Linker -> Input and add Irvine32.lib to Additional Dependencies

Program Basics

• .386 tells the assembler to use the .386 instruction set
• .model flat, stdcall
  • model is a directive specifying the memory model of the program, and flat is the model for Windows programs
  • stdcall is the method for passing parameters to Windows functions, indicating that parameters are pushed from right to left