Automatic generation of high-performance multipliers for FPGAs with asymmetric multiplier blocks

The introduction of asymmetric embedded multiplier blocks in recent Xilinx FPGAs complicates the design of larger multiplier sizes. The two different input bitwidths of the embedded multipliers lead to two different shifting factors for the partial product outputs. This makes even the most straightforward multiplier design less intuitive. In this paper, we present a methodology and set of equations to automatically generate the Verilog for a multiplier using asymmetric embedded multiplier cores. The presented technique also uses intelligent rearrangement of the multiplier block outputs into partial product terms to reduce the overall delay of the circuit. Multipliers created with our generator are faster and use fewer DSP blocks than those created using Xilinx Core Generator or by simply using the '*' operator in Verilog. It also uses fewer LUTs than those created using the '*' operator. Finally, the presented generator can create multipliers larger than possible with Core Generator, and is limited only by the number of available embedded multipliers.