In some cases only the " positive-going " or " negative-going " crossings are counted, rather than all the crossings-since, logically, between a pair of adjacent positive zero-crossings there must be one and only one negative zero-crossing.
12.
If the sign bit is 1 then the number is negative, although formats other than two's complement integers allow a signed zero : distinct " positive zero " and " negative zero " representations, the latter of which does not correspond to the mathematical concept of a negative number.
