"Optimized Synthesis of Sum-Of-Products"

R. Zimmermann and D. Q. Tran

Abstract
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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.