two's complement, was Re: Now OT

[Paul Koning]

> On Jun 23, 2016, at 12:07 PM, Al Kossow <aek at bitsavers.org> wrote:
> ...
> 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.

That's true.  It certainly can be done and has been. But since one's complement arithmetic uses end around carry, when you have multiple word you have to defeat the word carry and instead do the carry around the whole number.

	paul