[M3devel] integer division/mod questions?

[hendrik at topoi.pooq.com]

On Tue, Jan 19, 2010 at 06:39:22PM -0600, Rodney M. Bates wrote:
> 
> Tony, you were concerned about showing your age, but 20 years is but an
> evening past.  I remember programming ones-complement arithmetic
> in assembly language, definitely more decades ago than two.
> And that was not my first job.
> 
> There is a positive zero and a negative zero, and which one you get
> can depend on the operation and operand values that produced the
> result, so you have to check for both of them, often with two
> separate conditional branches.
> 
> Anyone remember nines- or tens-complement arithmetic on decimal
> machines?

Conputers, no.  The decimal computer I used has signed-magnitude 
representation.  And it did addition by looking pairs of digits up in an 
array in RAM.  YOu could get interesting effects by replacing the 
addition tables.

>  Electromechanical accounting machines?

Yes.  I remember using these when studying statistics.

-- hendrik