Instance Inhabitant_val : Inhabitant val := Vundef.Instance Inhabitant_int: Inhabitant int := Int.zero.Instance Inhabitant_byte: Inhabitant byte := Byte.zero.Instance Inhabitant_int64: Inhabitant Int64.int := Int64.zero.Instance Inhabitant_ptrofs: Inhabitant Ptrofs.int := Ptrofs.zero.Instance Inhabitant_float : Inhabitant float := Float.zero.Instance Inhabitant_float32 : Inhabitant float32 := Float32.zero.Definition Vubyte (c: Byte.int) : val :=
  Vint (Int.repr (Byte.unsigned c)).Definition Vbyte (c: Byte.int) : val :=
  Vint (Int.repr (Byte.signed c)).

Lemma ptrofs_add_assoc1: forall z i j, Ptrofs.add (Ptrofs.add z (Ptrofs.repr i)) (Ptrofs.repr j) = Ptrofs.add z (Ptrofs.repr (i+j)).