User guide

17-25
Using the PLI
Using Only the ACC Capabilities that You Need
There are compile-time and runtime options that enable VCS and PLI
applications to use only the ACC capabilities they need and no more
than they need. The procedure to use these options is as follows:
1. Use the +vcs+learn+pli runtime option to tell VCS to keep
track of, or learn, the ACC capabilities that are used by different
modules in your design. VCS uses this information to create a
secondary PLI table file, named pli_learn.tab, that you can use to
recompile your design so that subsequent simulations only use
the ACC capabilities that they need.
2. Tell VCS to apply what it has learned in the next compilation of
your design, and specify the secondary PLI table file, with the
+applylearn+filename compile-time option (if you omit
+filename from the +applylearn compile-time option, VCS
uses the pli_learn.tab secondary PLI table file).
3. Simulate again with a simv executable in which only the ACC
capabilities you need are enabled.
Learning What ACC Capabilities are Used
You include the +vcs+learn+pli runtime option to tell VCS to learn
the ACC capabilities that were used by the modules in your design
and write them into a secondary PLI table file named pli_learn.tab.
We call this file a secondary PLI table file because it does not replace
the first PLI table file that you used (if you used one). This file does
however modify what ever ACC capabilities are specified in a first PLI
table file, or other means of specifying ACC capabilities, so that you
enable only the ACC capabilities you need in subsequent simulations.