http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48906
--- Comment #15 from Thomas Henlich <thenlich at users dot sourceforge.net> 2011-05-31 06:05:19 UTC --- I hadn't really thought of that, but now I see what a PITA a scale factor > 0 is going to be (scale factor < 0 is simply padding with zeros and shifting digits): We have to ignore the scale factor, until we decide that we use E editing, at which point we need an additional digit in the result. For efficiency: Maybe we can "decide that we use E editing" without actually overwriting the original digits at that point yet, so we can go back when we actually switch to E editing and re-do the rounding with the extra digit.
