Omitting the Final Adder

You can choose not to instantiate the final adder in the multiplier and add up the two buses Mult0 and Mult1 to the final result later in the design flow. This is often the most efficient implementation when a lot of partial results get summed up in a large summation network. The following figure shows an example for Y = (A x B) + C + D using the multiplier with two outputs in combination with the Array-Adder.