Patent ID: 8856614
Filing Date: 2014-10-07
Classification: G06F

Abstract:
1. A semiconductor memory device comprising: a data comparator which compares first data which is write target data before write in a memory unit, with second data written in the memory unit and then read out; a data backup unit which stores the first data if a comparison result from the data comparator indicates mismatch; an address backup unit which stores a write address corresponding to the write target data if the comparison result from the data comparator indicates mismatch; an address comparator which compares a read address corresponding to read target data with an address stored in the address backup unit; a selector which selects data read out from the memory unit in accordance with the read address as the read target data if a comparison result from the address comparator indicates mismatch, and selects data read out from the data backup unit as the read target data if the comparison result from the address comparator indicates match; and a controller which rewrites in the memory unit the data read out from the data backup unit selected by the selector dependent on the comparison result of the address comparator using the address stored in the address backup unit based upon the comparison result of the data comparator, if neither a write operation nor read operation executes.