A programmable base 2D-LNS MAC with self-generated look-up tables

This paper presents a new architecture for a programmable second base 2-dimensional logarithmic number system (2D LNS) Multiply Accumulator Cell (MAC) using DRAMs to store the conversion look-up tables (LUTs). It uses a direct mapping from non-binary exponents to binary format with a 50% reduction in DRAM size compared to a recently reported architecture. With a simple modification of the DRAM data loading structure, each MAC can build its own LUT specific to the non-binary exponents of 2D-LNS coefficients in a pipelined data flow. This results not only in a considerable reduction of DRAM size, but also in the elimination of adders normally required for computing non-binary exponents in a data filtering channel.