A multipath accessible semiconductor memory device provides an interface function between processors. The memory device may include a memory cell array having a shared memory area operationally coupled to two or more ports that are independently accessible by two or more processors, an access path forming unit to form a data access path between one of the ports and the shared memory area in response to external signals applied by the processors, and an interface unit having a semaphore area and mailbox areas accessible in the shared memory area by the two or more processors to provide an interface function for communication between the two or more processors.