Professional Assembly Language

Chapter 13. Using Inline Assembly

Now that you know the basics of assembly language programming, it's time to start putting those concepts to practical use. One very common use of assembly language programming is to code assembly functions within higher-level languages, such as C and C++. There are a couple of different ways to do this. This chapter describes how to place assembly language functions directly within C and C++ language programs. This technique is called inline assembly.

The chapter begins by describing how C and C++ programs use functions, and how the functions are converted to assembly language code by the compiler. Next, the basic inline assembly format is discussed, including how to incorporate simple assembly functions. After that, the extended inline assembly format is described. This format enables you to incorporate more complex assembly language functions within the C or C++ programs. Finally, the chapter explains how to define macros using complex inline assembly language functions within C programs.

What Is Inline Assembly?

In a standard C or C++ program, code is entered in the C or C++ syntax in a text source code file. The source code file is then compiled into assembly language code using the compiler. After that step, the assembly language code is linked with any required libraries to produce an executable program (see Chapter 3, "The Tools of the Trade").

In the Linux world, the GNU compiler (gcc) is used to create the executable program from the text source ...