Definition Bsqrt sqrt_nan m x :=
  let f pl := B754_nan (fst pl) (snd pl) in
  match x with
  | B754_nan sx plx => f (sqrt_nan x)
  | B754_infinity false => x
  | B754_infinity true => f (sqrt_nan x)
  | B754_finite true _ _ _ => f (sqrt_nan x)
  | B754_zero _ => x
  | B754_finite sx mx ex Hx =>
    FF2B _ (proj1 (Bsqrt_correct_aux m mx ex Hx))
  end.

Theorem Bsqrt_correct : forall sqrt_nan m x, B2R (Bsqrt sqrt_nan m x) = round radix2 fexp (round_mode m) (sqrt (B2R x)) /\ is_finite (Bsqrt sqrt_nan m x) = match x with B754_zero _ => true | B754_finite false _ _ _ => true | _ => false end /\ (is_nan (Bsqrt sqrt_nan m x) = false -> Bsign (Bsqrt sqrt_nan m x) = Bsign x).