(Description from the GHDL home page ): . GHDL is a VHDL simulator, using the GCC technology. . VHDL is a language standardized by the IEEE, intended for developing electronic systems. . GHDL implements the VHDL language according to the IEEE 1076-1987 or the IEEE 1076-1993 standard. GHDL compiles VHDL files and creates a binary which simulates (or executes) your design. . GHDL does not do synthesis: it cannot translate your design into a netlist.