Separate Printing Mantissa and Exponent of a Floating Point

["Nordlöw" via Digitalmars-d-learn]

On Monday, 11 August 2014 at 15:30:30 UTC, Justin Whear wrote:
> 1. http://dlang.org/phobos/std_bitmanip.html#.FloatRep

Could someone briefly outline the algorithm that converts the 
fraction part of FloatRep into a string in base 10?

My first guess is

sum = 0;

foreach (bit_index i, bit_value b; fraction)
     if (b == 1)
         sum += 2^^(-i);

return to!string(sum);

/Per