Abstract: A device for transferring data arrays between at least two buses, the device comprising storage means for storing at least one data array, a first input/output interface for transferring data arrays in a first direction from a first of the buses (RBUS) to the storage means and in a second direction from the storage means to the first bus (RBUS), a second input/output interface for transferring data arrays in a third direction from a second of the buses (MBUS) to the storage means and in a fourth direction from the storage means to the second bus (MBUS), the first and second interfaces being concurrently operable in each clock cycle, the device comprising means for receiving an instruction word within a clock cycle, the first interface being provided with first selecting means for selecting one of said first and second directions and the second interface being provided with second selecting means for selecting one of said third and fourth directions, the first and second selecting means being connected to said