Definition mbed_tls_fround_col (col0 col1 col2 col3 : int) (rk : Z) : int :=
  (Int.xor (Int.xor (Int.xor (Int.xor (Int.repr rk)
    (Znth (byte0 col0) FT0 Int.zero))
    (Znth (byte1 col1) FT1 Int.zero))
    (Znth (byte2 col2) FT2 Int.zero))
    (Znth (byte3 col3) FT3 Int.zero)).

Lemma mbed_tls_fround_col_def: mbed_tls_fround_col = fun (col0 col1 col2 col3 : int) (rk : Z) => (Int.xor (Int.xor (Int.xor (Int.xor (Int.repr rk) (Znth (byte0 col0) FT0 Int.zero)) (Znth (byte1 col1) FT1 Int.zero)) (Znth (byte2 col2) FT2 Int.zero)) (Znth (byte3 col3) FT3 Int.zero)).