Patent ID: 6973551

Claim:
A method for a director to perform an atomic read-modify-write operation on plural bit read data stored in a selected one of a plurality of memory locations, comprising: providing a plurality of successive full adders, each one of the full adders being associated with a corresponding one of the bits of the plural bit read data, each one of the full adders having: a summation output; a carry bit input; and a carry bit output; summing in each one of the full adders: (a) a corresponding bit of plural bit input data provided by the director; (b) the corresponding one of the bits of the plural bit read data; and, (c) a carry bit fed the carry bit input from a preceding full adder, each one of the full adders producing: (a) a carry bit on the carry output thereof representative of the most significant bit produced by the full adder; and, (b) a bit on the summation output representative of a least significant bit produced by the full adder; storing the summation output in a corresponding bit location in the selected one of a plurality of memory locations; and selectively coupling, or inhibited from coupling, the carry bit produced by one of the full adders to the carry bit input of a next successive full adder selectively in accordance with a corresponding bit of a plural bit carry bit mask provided by the director.