From CPUDev Wiki
VHDL (VHSIC Hardware Description Language) is a hardware description language that is used to describe digital (and mixed-signal) systems such as field programmable gate arrays and integrated circuit.
- Strong Typing - catches such mistakes as bus precision and type mismatches before you synthesise and test your design;
- Custom Enumerated Types - define named values makes code more readable and helps catch errors in combination with type checking;
- Custom Record Types - group signals together, improves code readability.
- Verboseness - VHDL syntax is very verbose;
- Strong Typing - strong typing also means you need to convert(cast) between different types even if they are similar (i.e. signed to unsigned).
Free and Open Source:
- Bryan Mealy, Fabrizio Tappero (February 2012). freerangefactory.org. The no-frills guide to writing powerful VHDL code.
- Very High Speed Integrated Circuit