PROCESSING DEVICE

PURPOSE:To simplify an entire processing device, by fixing a specific address line to a specific level at the state that the supply line is opened, in a processor of which sub-storage section is in removable state. CONSTITUTION:When a sub-storage unit 21 is fitted, the level of address lines 9-12 is determined with signal lines 9'-12', and when a jump instruction JMP6 of a program in a main storage 1 is executed, normal jumping of sub-storage section to an address 6 is excuted. When a sub-storage unit is removed, the signal line 9 is opened and the address line 9 is pulled up with a fixed circuit 4 and fixed to the level 1. When the jump instruction JMP6 is executed, the address jumped to an address 6 in the address space of the main storage 1.