Instance CompSpecs : compspecs.(*
Definition EightWord (q:QuadWord * QuadWord) (v:val) : mpred :=
  match q with ((q0, q1, q2, q3),(q4, q5, q6, q7)) =>
    data_at Tsh (Tarray tuchar 4 noattr) (map Vint [q0; q1; q2; q3; q4; q5; q6; q7]) v
  end.*)
Definition QuadByte2ByteList (B:QuadByte) : list byte :=
  match B with (b0, b1, b2, b3) => [b0; b1; b2; b3]
  end.Definition QuadByte2ValList (B:QuadByte) : list val :=
   map Vint (map Int.repr (map Byte.unsigned (QuadByte2ByteList B))).

Lemma QuadByteValList_length q: length (QuadByte2ValList q) = 4%nat.