Abstract: A memory device includes: a memory including a first port and a second port that are accessible; an error check and correct encoding circuit that applies an error check and correct code to data and writes them into the first port of the memory; an error check and correct decoding circuit that receives input of the data and the error check and correct code read from the first port of the memory, and corrects the inputted data in case of an error in the inputted data is detected based on the inputted error check and correct code; and a control circuit that writes the corrected data and the error check and correct code into the second port of the memory in case of the error is detected and a current access address and a previous access address to the first port of the memory are different.

Abstract: A memory device includes: a memory including a first port and a second port that are accessible; an error check and correct encoding circuit that applies an error check and correct code to data and writes them into the first port of the memory; an error check and correct decoding circuit that receives input of the data and the error check and correct code read from the first port of the memory, and corrects the inputted data in case of an error in the inputted data is detected based on the inputted error check and correct code; and a control circuit that writes the corrected data and the error check and correct code into the second port of the memory in case of the error is detected and a current access address and a previous access address to the first port of the memory are different.

Abstract: The present invention provides a method for changing output data of a multiple-port semiconductor memory device, including memory cells, first and second bit lines connected to the memory cells, a first port connected to the first bit line to write data to the memory cells, a second port connected to the second bit line to output data stored in the memory cells, and a data read circuit connected to the second bit line and having a latch circuit for holding the data of one of the memory cells. The method of the present invention detects a change in the stored data in the memory cell associated with the data held by the latch circuit based on a potential at the second bit line, and changes the data held by the latch circuit when a change in the stored data is detected.