Hi, The C51 manual states that and how the Contiguous Adressing mode of the 80c390 etc. is supported. However, if I would like to use the Paged Addressing mode? This mode also uses 22 bit pointers, but the extended bits have to be maintained by the programmer. The difference (and theoretically a big advantage) to normal "classical" bank switching is that you can have up to three different banks, which are addressed by the extended PC, DPTR and R0/R1 pointers. But if the C compiler is not aware of it, these pointers are useless. Best Regards Joachim