IRSIM is an event-driven logic-level simulator for MOS circuits.

To run irsim, users should set CAD_HOME to the base installation directory
where magic was installed, e.g. /usr/local.  Alternatively, the system
administrator can create a dummy user named 'cad' with its home
directory set to the installation directory.

WWW: http://opencircuitdesign.com/irsim/