This paper describes new software called NLSoft, developed for the design of nonlinear controllers based on the well-known feedback linearization technique. NLSoft is a software package containing several symbolic manipulation modules, which includes differential geometric tools for the design and simulation of control systems. NLSoft presents a user-friendly graphical user interface (GUI) as well as a new and powerful module permitting the calculation time of linearizing control laws considering several digital signal processors (DSPs) characteristics. These facilitate the real-time implementation of the control system. NLSoft is validated considering a six order dynamic nonlinear system.