Why don't we switch to C like floating pointed arithmetic instead of automatic expansion to reals?

[Fool via Digitalmars-d]

On Thursday, 4 August 2016 at 20:00:14 UTC, Walter Bright wrote:
> On 8/4/2016 12:03 PM, Fool wrote:
>> How can we ensure that toFloat(toFloat(x) + toFloat(y)) does 
>> not involve
>> double-rounding?
>
> It's the whole point of it.

I'm afraid, I don't understand your implementation. Isn't 
toFloat(x) + toFloat(y) computed in real precision (first 
rounding)? Why doesn't toFloat(toFloat(x) + toFloat(y)) involve 
another rounding?