for a description of how to solve this problem. *)
Definition samerep (ch1 ch2: memory_chunk) (v1 v2: val) :=
Memdata.size_chunk ch1 = Memdata.size_chunk ch2 /\
forall bl: list Memdata.memval,
Memdata.size_chunk ch1 = Z.of_nat (length bl) ->
(Memdata.decode_val ch1 bl = v1 <-> Memdata.decode_val ch2 bl = v2).

Lemma float32_to_bits_abs:
forall x, Float32.to_bits (Float32.abs x) = Int.and (Float32.to_bits x) (Int.repr (2 ^ 31 - 1)).