Pillars of VLSI Design - Hardware Description Languages ( HDLs )
As the size and complexity of digital systems increased, more EDA Tools were introduced into the hardware design process. The early paper and pencil design methods have long given way to sophisticated design tools. The latest entrants into this design methodology are Hardware Description Languages ( HDLs ). They have now changed the process of VLSI Design to an extent unimaginable.
They are used to describe hardware for the purpose of Modeling, Designing, Simulation, Synthesis, Verification and Documentation.
The two most common HDLs are,
VHDL – Very High Speed Integrated Circuit Hardware Description Language and VERILOG .

Support for VLSI design comes from companies like Mentor Graphics, Synplicity, Synopsys, Exemplar, Aldec, Xilinx. They have become the backbone of VLSI Design industry. All these tool support both, VHDL and VERILOG.