MPF fits in 64bit double?

[Julien D Arques]

Hi,

In my algorithm, I need to repeat some calculations up to the point the mpf
result fits in a double (8bytes on x86_64) without loss.

I plan to use the mpf_fits_ulong_p function because it is 8 bytes as well,
even if not a double.
It would warrant that 64bits (and no more) are in use to store the current
result.

Is it a problematic reasoning?

Thanks,