On a Bit-Serial Input and Bit-Serial Output Multiplier

A recent paper by Chen and Willoner [1] forwarded a bit-sequential input and output (LSBfirst) multiplier for positive numbers. This multiplier for n-bit operands requires 2n clocks and 2n number of five-input adder modules. In this correspondence, after a brief discussion on the different claims made by the authors of [1] and their limitations, we show that this multiplier can be realized with only n adder modules. The technique is extended to two's complement number system. Also, a more complete picture of the actual implementation is depicted. Finally, we bring to the attention an already existing multiplier which fits into the bit-sequential multiplier category.