ModelSim SE User's Manual - Electrical and Computer Engineering

UM-398 15 - Functional coverage with PSL and ModelSim
Creating a reactive testbench with endpoint directives
ModelSim SE User’s Manual
The PSL endpoint construct is designed to create a symbol in HDL that is set to TRUE for
the simulation time unit when a sequence is matched. The HDL code may test the endpoint
variable thereby allowing the testbench to take some action when a sequence occurs. If the
sequence is used for both an endpoint and a cover directive, this is equivalent to writing a
"reactive" testbench that can alter its behavior when a sequence is covered.
The following example shows an endpoint and a cover that are derived from the same
sequence. Note that the embedded PSL with the endpoint declaration for
endpoint_a_after_b has to appear before the VHDL process in which the
endpoint_a_after_b signal is tested.
library ieee;
use ieee.std_logic_1164.all;
use std.textio.all;
entity test is
end entity test;
architecture t of test is
signal clk : std_logic := '0';
signal a : std_logic := '0';
signal b : std_logic := '0';
begin
clk