Notation bpow e := (bpow beta e).

Theorem relative_error_FLT_F2R_emin : forall m, let x := F2R (Float beta m emin) in (x <> 0)%R -> (Rabs (round beta (FLT_exp emin prec) rnd x - x) < bpow (-prec + 1) * Rabs x)%R.