Optimized synthesis of sum-of-products

In our latest approach to datapath synthesis from RTL, datapaths are extracted into largest possible sum-of-product (SOP) blocks, thus making extensive use of carry-save intermediate results and reducing the number of expensive carry-propagations to a minimum. The sum-of-product blocks are then implemented by constraint- and technology-driven generation of partial products, carry-save adder tree and carry-propagate adder. A smart generation feature selects the best among alternative implementation variants. Special datapath library cells are used where available and beneficial. All these measures translate into better performing circuits for simple and complex datapaths in cell-based design.