User guide

17-2
Using the PLI
• Probabilistic distribution
• Returning a string pointer to a parameter value
• Extended VCD files
• Line callbacks
• Source protection
• Signal in a generate block
ACC routines, which access the values in a design, changing, for
example, the delay values of module paths or the simulation values
of individual signals, are more powerful that the TF routines which
operate only on data passed to them. However, the ACC routines
also have a greater performance cost. The ability of ACC routines to
traverse the entire design and make extensive value changes
requires VCS to omit powerful performance optimizations so that it is
possible for the ACC routines to make these changes.
This performance cost of the ACC routines is a major consideration
in VCS performance. There are ways to limit this performance cost
and doing so is an important step in developing a PLI application that
uses ACC routines.
This chapter covers the following topics:
• Writing a PLI Application
• Functions in a PLI Application
• Header Files for PLI Applications
• The PLI Table File
• Enabling ACC Capabilities