Chris G. Demetriou wrote:
> 
> > Situation:
> >       1 Casting a negative floating point number to a unsigned integer
> > also
> >       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???
> 
> At least under Digital UNIX, the division/remainder rules appear to
> be:
> 
>         x = N / M
>         y = N % M
> 
> constrained by:
> 
>         x * M + y == N
> 
>         N / M == -((-N) / M )
>         N % M == -((-N) % M )
> 
>         N / M == -(N / (-M))
>         N % M == N % (-M)
> 
> In other words:
> 
> 443 [dnaunix] tmp % cat bar.c
> 
> main(){
>         printf("%d\n", 12 / 5);
>         printf("%d\n", 12 % 5);
> 
>         printf("%d\n", - 12 / 5);
>         printf("%d\n", - 12 % 5);
> 
>         printf("%d\n", 12 / - 5);
>         printf("%d\n", 12 % - 5); ------------------------------
>								  |
>         printf("%d\n", -12 / - 5);				  |
>         printf("%d\n", -12 % - 5);				  |
> }								  |
> 444 [dnaunix] tmp % cc bar.c
> 445 [dnaunix] tmp % ./a.out
> 2
> 2
> -2
> -2
> -2
> 2
> 2
> -2

'BSD retains this functionality for ints, but for quads the one hilited
above different (gives -2). Does this mean that the NetBSD moddi3
function should not return negative numbers?

	Neil

-- 
Neil A. Carson                         Marketing Director
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