  We propose a reconfigurable bit comparator implemented with a nanowire spin
valve whose two contacts are magnetostrictive with bistable magnetization.
Reference and input bits are "written" into the magnetization states of the two
contacts with electrically generated strain and the spin-valve's resistance is
lowered if they match. Multiple comparators can be interfaced in parallel with
a magneto-tunneling junction to determine if an N-bit input stream matches an
N-bit reference stream bit by bit. The system is robust against thermal noise
at room temperature and a 16-bit comparator can operate at roughly 416 MHz
while dissipating at most 420 aJ per cycle.
