The MC14580B is a 4 by 4 multiport register useful in small scratch pad memories, arithmetic operations when coupled with an adder, and other data storage applications. It allows independent reading of any two words (or the same word at both outputs) while writing into any one of four words. Address changing and data entry occur on the rising edge of the clock. When the write enable input is low, the contents of any word may be accessed but not altered.