IMPLEMENTING LARGE MULTIPLIERS IN A PROGRAMMABLE INTEGRATED CIRCUIT DEVICE

A specialized processing block is configurable as one ternary linear decomposition or two binary linear decompositions to perform large multiplications using smaller multipliers, and includes a first number of multiplier circuits of a first size, a second number of pre-adders, and a third number of block inputs. The block inputs are connected to a first subset of the multiplier circuits, and to the pre-adders which are connected to a second subset of the multiplier circuits. There is also a fourth number of additional inputs. A plurality of shifters shift partial product outputs of each of the multipliers by various shift amounts. A joint adder structure combines the shifted partial products. Controllable elements controllably select between different configurations of inputs to the multipliers and pre-adders, controllably connect and disconnect certain ones of the shifted partial products, and selectively split the joint adder structure into two smaller adder structures.