guideline

Use incremental schemes instead of mod and rem when measured performance indicates.

   -- Using mod
   for I in 0 .. N loop
      Update (Arr (I mod Modulus));
   end loop;

   -- Avoiding mod
   J := 0;
   for I in 0 .. N loop
      Update (Arr (J));
      J := J + 1;
      if J = Modulus then
         J := 0;
      end if;
   end loop;

rationale

Determine the impact of using the mod and rem operators. One of the above styles may be significantly more efficient than the other.