Hi Florian, I do nut really understand why you return a mantissa with the highest bit stripped off for type Extended. >From what I have gathered about 80-bit extended type the mantissa of this type _is_ the full 64 bits, see http://rvelthuis.de/articles/articles-floats.html Does Delphi strip that bit off as well in TExtended80Rec.Mantissa? Bart