"What's New In VHDL 2006 - An Insider's Perspective"

Jaroslaw Kaczynski


VHDL is the most popular Hardware Description Language (HDL) for digital circuit design in military applications. Originally created in 1987, it was significantly upgraded in 1995, and underwent minor changes in 2002. With the emergence of SystemC and SystemVerilog, VHDL standard IEEE Std 1076-2002 has started showing signs of aging, triggering the largest and probably most important overhaul of the language to date. A group of experts from the industry, sponsored by the Accellera organization (VHDL Technical Committee) has focused on addressing existing issues in VHDL and adding important, new features to the language.

      To unify multiple standards branching from the original standard, the new version of the language merges IEEE Std 1164-1993 (dealing with standard logic types), IEEE Std 1076.2-1996 (defining MATH_REAL and MATH_COMPLEX packages) and IEEE Std 1076.3-1997 (introducing NUMERIC_STD and NUMERIC_BIT packages) with the core language standard.

      Synthesizable packages supporting fixed-point arithmetic are one of the new elements of the language.

      With all important packages in one standard, existing operators can be unified (e.g. shift operators) and new operators can be added (e.g. unary reduction operators).

      VHPI interface between VHDL and C/C++ code is introduced as the part of the new standard.

      Minimal subset of Property Specification Language (PSL) significantly enhances assertions support in VHDL.

      Support for Intellectual Property (IP) encryption/decryption is added.

      Generate statements are improved: if..generate gets elsif / else clauses, case..generate is introduced.

      Multiple additional enhancements, addressed in the paper.

The paper briefly summarizes the history of the language, and then proceeds to the presentation and analysis of corrected issues and new features of the forthcoming standard. Benefits to VHDL designers are highlighted, with special attention paid to military applications. Since the author participates in development of the new standard, the paper will contain the most up-to-date information about the standard.



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