Section Fcalc_round_fexp.
Variable fexp : Z -> Z.
Context { valid_exp : Valid_exp fexp }.
Notation format := (generic_format beta fexp).

Theorem cexp_inbetween_float :
forall x m e l,
(0 < x)%R ->
inbetween_float beta m e x l ->
(e <= cexp beta fexp x \/ e <= fexp (Zdigits beta m + e))%Z ->
cexp beta fexp x = fexp (Zdigits beta m + e).