Thanks for the link @kparzysz , I didn’t know about Q numbers.
I agree on expressing the intrinsic in terms of Q numbers, but I don’t follow when you say that x and m are interchangeable.
The point is that fpm(x,m,s) multiplies x (which is not a Q number) by a Q1.30 number (I think) described by m and s.
How can I exchange m with x?