Partial write control apparatus

摘要

In a partial write control apparatus for a memory having a high speed operation mode such as a nibble mode or a page mode, when a partial write request for a plurality of words including those which require partial write is received, a memory control signal generator causes the memory to read successively all the words requiring partial write in a single high speed operation mode read cycle. A merging circuit merges those portions of the read-out words which need no alteration with write data and forms a group of updated complete words. Then, the memory control signal generator causes the memory to write successively these words in a single high speed operation mode write cycle.