A recursive carry-lookahead/carry-select hybrid adder

The author presents a very fast adder for double-precision mantissas, which is an improvement on T. Lynch and E. E. Swartzlandes, Jr.'s spanning tree carry lookahead adder or redundant cell adder (see ibid., vol. 41, 1992) which was implemented using the Am29050 microprocessor. The adder presented is faster than theirs mainly because Manchester carry chains of various lengths are used instead of chains all of the same length.<
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