GPL Cver is a full 1995 P1364 Verilog standard HDL simulator. It also
implements some of the 2001 P1364 standard features including all three
PLI interfaces (tf_, acc_ and vpi_) as defined in the 2001 Language
Reference Manual (LRM).

Verilog is the name for both a language for describing electronic hardware
called a hardware description language (HDL) and the name of the program
that simulates HDL circuit descriptions to verify that described circuits
will function correctly when the are constructed. Verilog is used only for
describing digital logic circuits. Other HDLs such as Spice are used for
describing analog circuits. There is an IEEE standard named P1364 that
standardizes the Verilog HDL and the behavior of Verilog simulators.
Verilog is officially defined in the IEEE P1364 Language Reference
Manual (LRM) that can be purchased from IEEE. There are many good books
for learning that teach the Verilog HDL and/or that teach digital circuit
design using Verilog.

WWW: http://www.pragmatic-c.com/gpl-cver/