On 6/23/16 8:17 AM, Chuck Guzis wrote: > On 06/23/2016 07:31 AM, Paul Koning wrote: > >> I have a copy of 1948 (!) lecture notes on computer design. It >> discusses one's complement and two's complement. It points out the >> advantage of two's complement (no two zeroes) but also the >> disadvantage that negating is harder (requiring two steps). In early >> computers that was significant, which explains why you see one's >> complement there. > > There are also a few obscure bit-twiddling tricks that work in ones > complement, but not in two's. >
I have also heard that 2s compliment was popular in shorter word length machines because 1s compliment multiple precision arithmetic is a PITA to implement.
