Semiconductor memory device having means for replacing defective memory cells

A semiconductor memory device, comprising:

• first memory means including memory cells for prestoring fixed data;
• decoder means for decoding an input address and for reading out a fixed data from said first memory means based on a decoded input address;
• second memory means for storing a data identical to that prestored in a defective memory cell of said first memory means, wherein said second memory means includes programmable non-volatile memory cells;
• discriminating means including third memory means for storing a redundant address corresponding to each defective memory cell of said first memory means for discriminating whether or not the input address coincides with the redundant address and for outputting a discrimination signal when the input address coincides with the redundant address;
• and
• selecting means supplied with data read out from said first and second memory means for normally outputting the data read out from said first memory means and for selectively outputting the data from said second memory means when the discrimination signal is received from said discriminating means,
• wherein said first memory means comprises a plurality of memory cells which are arranged in rows and columns, said third memory means storing a redundant address of rows and columns of said first memory means which include a defective memory cell, and said selecting means replacing the data read out from said first memory means by the data from at least one of a corresponding row and column of said second memory means when the redundant address spans two adjacent rows or columns of said first memory means and the discrimination signal is received from said discriminating means, and
• wherein said discriminating means includes adding means for adding an integer L to the redundant address stored in said third memory means, and comparing means for outputting the discrimination signal when the input address coincides with one of the addresses received from said adding means and said third memory means.