PURPOSE: To provide the high speed, compact, and low-cost mapper circuit of a memory.

CONSTITUTION: A comparator circuit 18 compares the bit of a start address corresponding only to a mask bit which is not mask-set in a mask address register 15 with the bit of an emulation address without comparing the bit of the start address corresponding to the mask bit which is mask-set in the mask address register 15, with the bit of the emulation address. Only when the entire bits are matched, a matching signal is outputted, and the page address of a page address register 16 and the attribute of an attribute register 17 are outputted based on the matching signal.