3. The device of claim 2 , wherein the at least one memory location in common includes all the memory locations of one between the first and the second memory areas, and of the corresponding memory locations starting from a boundary of the other memory area.
3. The device of claim 2 , wherein the at least one memory location in common includes all the memory locations of one between the first and the second memory areas, and of the corresponding memory locations starting from a boundary of the other memory area. 6. The device of claim 3 , wherein the expansion means includes means for shifting a second subset of the symbols of each word to separate the second subset from a further second subset of the symbols of the word, and means for inserting at least one additional symbol between the second subset and the further second subset.