20 Mixing C/C++ and Assembly Language

Assembly language code can be mixed with C/C++ code using two different techniques: writing assembly code and placing it into a separate assembler module, or including it as in-line assembly in a C/C++ module. This section describes how to use assembly language and C/C++ modules together. It gives examples of using C/C++ variables and functions in assembly code, and examples of using assembly language variables and functions in C/C++.

The more assembly code a project contains, the more difficult and time consuming its maintenance will be. As the project is developed, the compiler may work in different ways as some optimizations look at the entire program. The assembly code is more likely to fail if the compiler is updated due to differences in the way the updated compiler may work. These factors do not affect code written in C/C++.