ModelSim
ModelSim is a multi-language environment by Mentor Graphics, for simulation of hardware description languages such as VHDL, Verilog and SystemC, and includes a built-in C debugger. ModelSim can be used independently, or in conjunction with Intel Quartus Prime, Xilinx ISE or Xilinx Vivado. Simulation is performed using the graphical user interface (GUI), or automatically using scripts. Coupled with the most popular HDL debugging capabilities in the industry, ModelSim is known for delivering high performance, ease of use, and outstanding product support. MicroSemi describes ModelSim as an easy-to-use graphical user interface enables you to quickly identify and debug problems, aided by dynamically updated windows. For example, selecting a design region in the Structure window automatically updates the Source, Signals, Process, and Variables windows. These cross linked ModelSim windows create an easy-to-use debug environment. Once a problem is found, you can edit, recompile, and re-simulate without leaving the simulator. ModelSim fully supports current VHDL and Verilog language standards.