🚀 go-pugleaf

rex@aussie.com wrote:

>There was considerable debate about whether or not integers could be stored 
>as BCD, Grey code, or some such, but in the end, we decided that they had to 
>be stored as binary numbers. And, of course, 2's comp, 1's comp, and signed 
>magnitude all use all-bits-zero for zero. The only thing that could cause a 
>problem is for machines/compilers with signed zeros; I think that negative 
>zero might have some other bit pattern.

Yes -- in one's complement, `-0' is represented with all bits set to 1.
With one's complement, the usual method of testing for 0 is something
like: `if (x+0 == 0)' since the addition of 0 normally produces a
positive 0.  If memory serves some of the more widely used one's
complement machines (e.g. CDC 6000/7000/Cyber's) had a pseudo-register
set to a constant value of 0 that came in handy for this.
(Unfortunately, they also used 6 bit characters, so a conforming
implementation of C would have been quite difficult anyway...)
    Later,
    Jerry.

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