"Neil A. Carson" writes:
[...]
>	2   12 % -5 (both long longs)
>
>Initially on the ARM we returned a NaN for the 1, (now zero) and the
>present long long code returns -2 --- surely this should be 2, and a
>remainder always be positive???
>
>Input welcomed.
>
>	Cheers,
>
>	Neil
>
>

I'm not 100% sure this is what you mean, but Hennessey and Patterson 
says that the values of the quotient and remainder should be 
unaffected by the sign.  Thus

12 / -5 = -2 R -2

since of course always (and this I think supercedes whatever one may 
believe about the sign of the remainder):

dividend * quotient + remainder = divisor

On the other hand, the "mathematical" modulus is always positive---thus,
if one is to believe H&P, there is a distinction between "remainder" and
"modulus," C's % being an example of the former.

#define mod(x,b) ( ((x)%(b) + (b))%(b) )

   Mika