Design of fixed-point rounding operators for the VHDL-2008 standard

The contemporary design of sophisticated digital signal processing platforms involves the use of specifications at an increasingly raised abstraction level. This scheme is dictated by the ever growing divide between available circuit complexity and developer productivity. Algorithm developers tend to use very high-level programming languages such as MATLAB in order to rapidly and seamlessly generate low-level design facets such as ANSI C reference implementations and synthesizable HDL code. In this paper, a generic and parameterized implementation of fixed-point rounding operators in the VHDL hardware description language is introduced. Most hardware compilation frameworks either lack the support of these operators or provide specialized and non-portable implementations. Further, this is the first time that an implementation for these operators is being proposed, that can take advantage of features only present in the VHDL-2008 standard. Compared to existing fixed-point rounding, the proposed combinatorial designs achieve lower timing by about 30% with similar area demands for the case of signed arithmetic compared to rival designs when realized on FPGAs.