Introduction - If you have any usage issues, please Google them yourself
VHDL Tutorial, it describes the modeling language VHDL. VHDL includes
facilities for describing logical structure and function of digital systems at a
number of levels of abstraction, from system level down to the gate level. It is intended,
among other things, as a modeling language for specification and simulation. We
can also use it for hardware synthesis if we restrict ourselves to a subset that can be
automatically translated into hardware.