Creating PLI Applications Using VPI Routines

Summary

This chapter has presented two short examples which illustrate how PLI applications are created using the VPI routine library in the PLI standard. The $hello PLI application showed how a Verilog simulation can execute another C program. The $show_value application illustrated how arguments can be passed from a Verilog simulation to a PLI application, and how the application can access information about the arguments.

The principles illustrated by the $show_value example can be readily expanded to provide much more powerful and useful capabilities. In Chapter 3, the functionality of $show_value will be extended to create an application called $list_nets, which automatically finds all nets in a module and prints the values of each net. Another example in the same chapter extends $show_value to create $list_signals, which automatically finds all nets, regs and variables in a module and prints the values of each one.

The next chapter presents much greater detail on how PLI applications interact with Verilog simulations. Subsequent chapters in Part One of this book will discuss the complete VPI library, and include many examples of how the VPI routines are used to create PLI applications which interact with Verilog simulators.