1.3 What is GHDL?

GHDL is a shorthand for G Hardware Design Language. Currently, G has no meaning.

GHDL is a VHDL compiler that can execute (nearly) any VHDL program. GHDL is not a synthesis tool: you cannot create a netlist with GHDL.

Unlike some other simulators, GHDL is a compiler: it directly translates a VHDL file to machine code, using the GCC back-end and without using an intermediary language such as C or C++. Therefore, the compiled code should be faster and the analysis time should be shorter than with a compiler using an intermediary language.

The Windows(TM) version of GHDL is not based on GCC but on an internal code generator.

The current version of GHDL does not contain any graphical viewer: you cannot see signal waves. You can still check with a test bench. The current version can produce a VCD file which can be viewed with a wave viewer, as well as ghw files to be viewed by ‘gtkwave’.

GHDL aims at implementing VHDL as defined by IEEE 1076. It supports most of the 1987 standard and most features added by the 1993 standard.