Double-least-significant-bits 2's-complement number representation scheme with bitwise complementation and symmetric range

A scheme is proposed for representing 2’s-complement binary numbers in which there are two least-significant bits (LSBs). Benefits of the extra LSB include making the number representation range symmetric (i.e. from 22 to 2 for k-bit integers), allowing sign change by simple bitwise logical inversion, facilitating multiprecision arithmetic and enabling the truncation of results in lieu of rounding. These advantages justify the added storage and interconnect costs stemming from the extra bit. Operation latencies show little or no change relative to conventional 2’s-complement arithmetic, thus making double-LSB representation attractive.