User guide

D-34
Compiler Directives and System Tasks
$enable_warnings("timing"[,module_instance,...]);
If you specify a module instance, this system task enables timing
violations for the specified instance and all instances
hierarchically under this instance.
If you omit module instances, this system task enables timing
violations throughout the design.
$hold
Reports a timing violation when a data event happens too soon
after a reference event.
See IEEE Std 1364-2001 pages 241-242.
$period
Reports a timing violation when an edge triggered event happens
too soon after the previous matching edge triggered event on a
signal.
See IEEE Std 1364-2001 pages 255-256.
$recovery
Reports a timing violation when a data event happens too soon
after a reference event. Unlike the $setup timing check, the
reference event must include the posedge or negedge keyword.
Typically the $recovery timing check has a control signal, such
as clear, as the reference event, and the clock signal as the data
event.
See IEEE 1364-2001 pages 245-246.