diff --git a/ml-proto/host/parser.mly b/ml-proto/host/parser.mly
index ad9416734b..3e4b0e3eed 100644
--- a/ml-proto/host/parser.mly
+++ b/ml-proto/host/parser.mly
@@ -7,7 +7,6 @@ open Source
 open Ast
 open Script
 
-
 (* Position handling *)
 
 let position_to_pos position =
@@ -36,8 +35,8 @@ let literal at s t =
     match t with
     | Types.Int32Type -> Values.Int32 (I32.of_string s) @@ at
     | Types.Int64Type -> Values.Int64 (I64.of_string s) @@ at
-    | Types.Float32Type -> Values.Float32 (F32.of_string s) @@ at
-    | Types.Float64Type -> Values.Float64 (F64.of_string s) @@ at
+    | Types.Float32Type -> Values.Float32 (Values.F32.of_string s) @@ at
+    | Types.Float64Type -> Values.Float64 (Values.F64.of_string s) @@ at
   with _ -> Error.error at "constant out of range"
 
 
diff --git a/ml-proto/spec/f32.ml b/ml-proto/spec/f32.ml
deleted file mode 100644
index af602d794a..0000000000
--- a/ml-proto/spec/f32.ml
+++ /dev/null
@@ -1,94 +0,0 @@
-(* WebAssembly-compatible f32 implementation *)
-
-(*
- * We represent f32 as its bits in an int32 so that we can be assured that all
- * the bits of NaNs are preserved in all cases where we require them to be.
- *)
-type t = int32
-type bits = int32
-
-(* TODO: Do something meaningful with nondeterminism *)
-let nondeterministic_nan = 0x7fc0f0f0l
-
-let of_float = Int32.bits_of_float
-let to_float = Int32.float_of_bits
-
-let of_bits x = x
-let to_bits x = x
-
-(* Most arithmetic ops that return NaN return a nondeterministic NaN *)
-let arith_of_bits = to_float
-let bits_of_arith f = if f <> f then nondeterministic_nan else of_float f
-
-let zero = of_float 0.0
-
-let add x y = bits_of_arith ((arith_of_bits x) +. (arith_of_bits y))
-let sub x y = bits_of_arith ((arith_of_bits x) -. (arith_of_bits y))
-let mul x y = bits_of_arith ((arith_of_bits x) *. (arith_of_bits y))
-let div x y = bits_of_arith ((arith_of_bits x) /. (arith_of_bits y))
-
-let sqrt  x = bits_of_arith (Pervasives.sqrt (arith_of_bits x))
-
-let ceil  x = bits_of_arith (Pervasives.ceil  (arith_of_bits x))
-let floor x = bits_of_arith (Pervasives.floor (arith_of_bits x))
-
-let trunc x =
-  let xf = arith_of_bits x in
-  (* preserve the sign of zero *)
-  if xf = 0.0 then x else
-  (* trunc is either ceil or floor depending on which one is toward zero *)
-  let f = if xf < 0.0 then Pervasives.ceil xf else Pervasives.floor xf in
-  bits_of_arith f
-
-let nearest x =
-  let xf = arith_of_bits x in
-  (* preserve the sign of zero *)
-  if xf = 0.0 then x else
-  (* nearest is either ceil or floor depending on which is nearest or even *)
-  let u = Pervasives.ceil xf in
-  let d = Pervasives.floor xf in
-  let um = abs_float (xf -. u) in
-  let dm = abs_float (xf -. d) in
-  let u_or_d = um < dm ||
-               (um = dm && let h = u /. 2. in Pervasives.floor h = h) in
-  let f = if u_or_d then u else d in
-  bits_of_arith f
-
-let min x y =
-  let xf = arith_of_bits x in
-  let yf = arith_of_bits y in
-  (* min -0 0 is -0 *)
-  if xf = yf then Int32.logor x y else
-  if xf < yf then x else
-  if xf > yf then y else
-  nondeterministic_nan
-
-let max x y =
-  let xf = arith_of_bits x in
-  let yf = arith_of_bits y in
-  (* max -0 0 is 0 *)
-  if xf = yf then Int32.logand x y else
-  if xf > yf then x else
-  if xf < yf then y else
-  nondeterministic_nan
-
-(* abs, neg, and copysign are purely bitwise operations, even on NaN values *)
-let abs x =
-  Int32.logand x Int32.max_int
-
-let neg x =
-  Int32.logxor x Int32.min_int
-
-let copysign x y =
-  Int32.logor (abs x) (Int32.logand y Int32.min_int)
-
-let eq x y = (arith_of_bits x) =  (arith_of_bits y)
-let ne x y = (arith_of_bits x) <> (arith_of_bits y)
-let lt x y = (arith_of_bits x) <  (arith_of_bits y)
-let gt x y = (arith_of_bits x) >  (arith_of_bits y)
-let le x y = (arith_of_bits x) <= (arith_of_bits y)
-let ge x y = (arith_of_bits x) >= (arith_of_bits y)
-
-(* TODO: OCaml's string_of_float and float_of_string are insufficient *)
-let of_string x = of_float (float_of_string x)
-let to_string x = string_of_float (to_float x)
diff --git a/ml-proto/spec/f32.mli b/ml-proto/spec/f32.mli
deleted file mode 100644
index 1174efaa43..0000000000
--- a/ml-proto/spec/f32.mli
+++ /dev/null
@@ -1,35 +0,0 @@
-(* WebAssembly-compatible f32 implementation *)
-
-type t
-type bits = int32
-
-val of_float : float -> t
-val to_float : t -> float
-val of_bits : bits -> t
-val to_bits : t -> bits
-
-val zero : t
-
-val add : t -> t -> t
-val sub : t -> t -> t
-val mul : t -> t -> t
-val div : t -> t -> t
-val sqrt : t -> t
-val min : t -> t -> t
-val max : t -> t -> t
-val ceil : t -> t
-val floor : t -> t
-val trunc : t -> t
-val nearest : t -> t
-val abs : t -> t
-val neg : t -> t
-val copysign : t -> t -> t
-val eq : t -> t -> bool
-val ne : t -> t -> bool
-val lt : t -> t -> bool
-val le : t -> t -> bool
-val gt : t -> t -> bool
-val ge : t -> t -> bool
-
-val of_string : string -> t
-val to_string : t -> string
diff --git a/ml-proto/spec/f32_convert.ml b/ml-proto/spec/f32_convert.ml
index 7dacfbcb1e..1843b4f139 100644
--- a/ml-proto/spec/f32_convert.ml
+++ b/ml-proto/spec/f32_convert.ml
@@ -1,3 +1,6 @@
+module F32 = Values.F32 
+module F64 = Values.F64
+
 (* WebAssembly-compatible type conversions to f32 implementation *)
 
 let make_nan_nondeterministic x = F32.mul x (F32.of_float 1.)
diff --git a/ml-proto/spec/f32_convert.mli b/ml-proto/spec/f32_convert.mli
index bcff3589b6..8ad79af6c1 100644
--- a/ml-proto/spec/f32_convert.mli
+++ b/ml-proto/spec/f32_convert.mli
@@ -1,8 +1,8 @@
 (* WebAssembly-compatible type conversions to f32 implementation *)
 
-val demote_f64 : F64.t -> F32.t
-val convert_s_i32 : I32.t -> F32.t
-val convert_u_i32 : I32.t -> F32.t
-val convert_s_i64 : I64.t -> F32.t
-val convert_u_i64 : I64.t -> F32.t
-val reinterpret_i32 : I32.t -> F32.t
+val demote_f64 : Values.F64.t -> Values.F32.t
+val convert_s_i32 : I32.t -> Values.F32.t
+val convert_u_i32 : I32.t -> Values.F32.t
+val convert_s_i64 : I64.t -> Values.F32.t
+val convert_u_i64 : I64.t -> Values.F32.t
+val reinterpret_i32 : I32.t -> Values.F32.t
diff --git a/ml-proto/spec/f64.ml b/ml-proto/spec/f64.ml
deleted file mode 100644
index 3c11879ef7..0000000000
--- a/ml-proto/spec/f64.ml
+++ /dev/null
@@ -1,94 +0,0 @@
-(* WebAssembly-compatible f64 implementation *)
-
-(*
- * We represent f64 as its bits in an int64 so that we can be assured that all
- * the bits of NaNs are preserved in all cases where we require them to be.
- *)
-type t = int64
-type bits = int64
-
-(* TODO: Do something meaningful with nondeterminism *)
-let nondeterministic_nan = 0x7fff0f0f0f0f0f0fL
-
-let of_float = Int64.bits_of_float
-let to_float = Int64.float_of_bits
-
-let of_bits x = x
-let to_bits x = x
-
-(* Most arithmetic ops that return NaN return a nondeterministic NaN *)
-let arith_of_bits = to_float
-let bits_of_arith f = if f <> f then nondeterministic_nan else of_float f
-
-let zero = of_float 0.0
-
-let add x y = bits_of_arith ((arith_of_bits x) +. (arith_of_bits y))
-let sub x y = bits_of_arith ((arith_of_bits x) -. (arith_of_bits y))
-let mul x y = bits_of_arith ((arith_of_bits x) *. (arith_of_bits y))
-let div x y = bits_of_arith ((arith_of_bits x) /. (arith_of_bits y))
-
-let sqrt  x = bits_of_arith (Pervasives.sqrt (arith_of_bits x))
-
-let ceil  x = bits_of_arith (Pervasives.ceil  (arith_of_bits x))
-let floor x = bits_of_arith (Pervasives.floor (arith_of_bits x))
-
-let trunc x =
-  let xf = arith_of_bits x in
-  (* preserve the sign of zero *)
-  if xf = 0.0 then x else
-  (* trunc is either ceil or floor depending on which one is toward zero *)
-  let f = if xf < 0.0 then Pervasives.ceil xf else Pervasives.floor xf in
-  bits_of_arith f
-
-let nearest x =
-  let xf = arith_of_bits x in
-  (* preserve the sign of zero *)
-  if xf = 0.0 then x else
-  (* nearest is either ceil or floor depending on which is nearest or even *)
-  let u = Pervasives.ceil xf in
-  let d = Pervasives.floor xf in
-  let um = abs_float (xf -. u) in
-  let dm = abs_float (xf -. d) in
-  let u_or_d = um < dm ||
-               (um = dm && let h = u /. 2. in Pervasives.floor h = h) in
-  let f = if u_or_d then u else d in
-  bits_of_arith f
-
-let min x y =
-  let xf = arith_of_bits x in
-  let yf = arith_of_bits y in
-  (* min -0 0 is -0 *)
-  if xf = yf then Int64.logor x y else
-  if xf < yf then x else
-  if xf > yf then y else
-  nondeterministic_nan
-
-let max x y =
-  let xf = arith_of_bits x in
-  let yf = arith_of_bits y in
-  (* max -0 0 is 0 *)
-  if xf = yf then Int64.logand x y else
-  if xf > yf then x else
-  if xf < yf then y else
-  nondeterministic_nan
-
-(* abs, neg, and copysign are purely bitwise operations, even on NaN values *)
-let abs x =
-  Int64.logand x Int64.max_int
-
-let neg x =
-  Int64.logxor x Int64.min_int
-
-let copysign x y =
-  Int64.logor (abs x) (Int64.logand y Int64.min_int)
-
-let eq x y = (arith_of_bits x) =  (arith_of_bits y)
-let ne x y = (arith_of_bits x) <> (arith_of_bits y)
-let lt x y = (arith_of_bits x) <  (arith_of_bits y)
-let gt x y = (arith_of_bits x) >  (arith_of_bits y)
-let le x y = (arith_of_bits x) <= (arith_of_bits y)
-let ge x y = (arith_of_bits x) >= (arith_of_bits y)
-
-(* TODO: OCaml's string_of_float and float_of_string are insufficient *)
-let of_string x = of_float (float_of_string x)
-let to_string x = string_of_float (to_float x)
diff --git a/ml-proto/spec/f64.mli b/ml-proto/spec/f64.mli
deleted file mode 100644
index 45631cd7a8..0000000000
--- a/ml-proto/spec/f64.mli
+++ /dev/null
@@ -1,35 +0,0 @@
-(* WebAssembly-compatible f64 implementation *)
-
-type t
-type bits = int64
-
-val of_float : float -> t
-val to_float : t -> float
-val of_bits : bits -> t
-val to_bits : t -> bits
-
-val zero : t
-
-val add : t -> t -> t
-val sub : t -> t -> t
-val mul : t -> t -> t
-val div : t -> t -> t
-val sqrt : t -> t
-val min : t -> t -> t
-val max : t -> t -> t
-val ceil : t -> t
-val floor : t -> t
-val trunc : t -> t
-val nearest : t -> t
-val abs : t -> t
-val neg : t -> t
-val copysign : t -> t -> t
-val eq : t -> t -> bool
-val ne : t -> t -> bool
-val lt : t -> t -> bool
-val le : t -> t -> bool
-val gt : t -> t -> bool
-val ge : t -> t -> bool
-
-val of_string : string -> t
-val to_string : t -> string
diff --git a/ml-proto/spec/f64_convert.ml b/ml-proto/spec/f64_convert.ml
index 2f9d5bdad9..5d46b138fa 100644
--- a/ml-proto/spec/f64_convert.ml
+++ b/ml-proto/spec/f64_convert.ml
@@ -1,3 +1,6 @@
+module F32 = Values.F32
+module F64 = Values.F64
+
 (* WebAssembly-compatible type conversions to f64 implementation *)
 
 let make_nan_nondeterministic x = F64.mul x (F64.of_float 1.)
diff --git a/ml-proto/spec/f64_convert.mli b/ml-proto/spec/f64_convert.mli
index a1209a3e70..a6529fa785 100644
--- a/ml-proto/spec/f64_convert.mli
+++ b/ml-proto/spec/f64_convert.mli
@@ -1,8 +1,8 @@
 (* WebAssembly-compatible type conversions to f64 implementation *)
 
-val promote_f32 : F32.t -> F64.t
-val convert_s_i32 : I32.t -> F64.t
-val convert_u_i32 : I32.t -> F64.t
-val convert_s_i64 : I64.t -> F64.t
-val convert_u_i64 : I64.t -> F64.t
-val reinterpret_i64 : I64.t -> F64.t
+val promote_f32 : Values.F32.t -> Values.F64.t
+val convert_s_i32 : I32.t -> Values.F64.t
+val convert_u_i32 : I32.t -> Values.F64.t
+val convert_s_i64 : I64.t -> Values.F64.t
+val convert_u_i64 : I64.t -> Values.F64.t
+val reinterpret_i64 : I64.t -> Values.F64.t
diff --git a/ml-proto/spec/float.ml b/ml-proto/spec/float.ml
new file mode 100644
index 0000000000..8db572b36e
--- /dev/null
+++ b/ml-proto/spec/float.ml
@@ -0,0 +1,93 @@
+module FloatPrims(Rep : Floatsig.REP) : Floatsig.FLOAT with type bits = Rep.t = 
+struct 
+  type t = Rep.t
+  type bits = Rep.t
+
+  let nondeterministic_nan = Rep.nondeterministic_nan
+
+  let of_float = Rep.bits_of_float
+  let to_float = Rep.float_of_bits
+		   
+  let of_bits x = x
+  let to_bits x = x
+
+  (* Most arithmetic ops that return NaN return a nondeterministic NaN *)
+  let arith_of_bits = to_float
+  let bits_of_arith f = if f <> f then Rep.nondeterministic_nan else of_float f
+
+  let zero = of_float 0.0
+
+  let add x y = bits_of_arith ((arith_of_bits x) +. (arith_of_bits y))
+  let sub x y = bits_of_arith ((arith_of_bits x) -. (arith_of_bits y))
+  let mul x y = bits_of_arith ((arith_of_bits x) *. (arith_of_bits y))
+  let div x y = bits_of_arith ((arith_of_bits x) /. (arith_of_bits y))
+
+  let sqrt  x = bits_of_arith (Pervasives.sqrt (arith_of_bits x))
+
+  let ceil  x = bits_of_arith (Pervasives.ceil  (arith_of_bits x))
+  let floor x = bits_of_arith (Pervasives.floor (arith_of_bits x))
+
+  let trunc x =
+    let xf = arith_of_bits x in
+    (* preserve the sign of zero *)
+    if xf = 0.0 then x else
+    (* trunc is either ceil or floor depending on which one is toward zero *)
+    let f = if xf < 0.0 then Pervasives.ceil xf else Pervasives.floor xf in
+    bits_of_arith f
+
+  let nearest x =
+    let xf = arith_of_bits x in
+    (* preserve the sign of zero *)
+    if xf = 0.0 then x else
+      (* nearest is either ceil or floor depending on which is nearest or even *)
+    let u = Pervasives.ceil xf in
+    let d = Pervasives.floor xf in
+    let um = abs_float (xf -. u) in
+    let dm = abs_float (xf -. d) in
+    let u_or_d = um < dm || 
+                 (um = dm && let h = u /. 2. in Pervasives.floor h = h) in
+    let f = if u_or_d then u else d in
+    bits_of_arith f
+
+  let min x y =
+    let xf = arith_of_bits x in
+    let yf = arith_of_bits y in
+    (* min -0 0 is -0 *)
+    if xf = yf then Rep.logor x y else
+    if xf < yf then x else
+	if xf > yf then y else
+	nondeterministic_nan
+
+  let max x y =
+    let xf = arith_of_bits x in
+    let yf = arith_of_bits y in
+    (* max -0 0 is 0 *)
+    if xf = yf then Rep.logand x y else
+    if xf > yf then x else
+	if xf < yf then y else
+	nondeterministic_nan
+
+  (* abs, neg, and copysign are purely bitwise operations, even on NaN values *)
+  let abs x =
+    Rep.logand x Rep.max_int
+
+  let neg x =
+    Rep.logxor x Rep.min_int
+
+  let copysign x y =
+    Rep.logor (abs x) (Rep.logand y Rep.min_int)
+
+  let eq x y = (arith_of_bits x) =  (arith_of_bits y)
+  let ne x y = (arith_of_bits x) <> (arith_of_bits y)
+  let lt x y = (arith_of_bits x) <  (arith_of_bits y)
+  let gt x y = (arith_of_bits x) >  (arith_of_bits y)
+  let le x y = (arith_of_bits x) <= (arith_of_bits y)
+  let ge x y = (arith_of_bits x) >= (arith_of_bits y)
+
+  let size = Rep.size
+
+  (* TODO: OCaml's string_of_float and float_of_string are insufficient *)
+  let of_string x = of_float (float_of_string x)
+  let to_string x = string_of_float (to_float x)
+end
+
diff --git a/ml-proto/spec/float.mli b/ml-proto/spec/float.mli
new file mode 100644
index 0000000000..3f508d5447
--- /dev/null
+++ b/ml-proto/spec/float.mli
@@ -0,0 +1 @@
+module FloatPrims : functor (Rep : Floatsig.REP) -> Floatsig.FLOAT with type bits = Rep.t
diff --git a/ml-proto/spec/floatsig.ml b/ml-proto/spec/floatsig.ml
new file mode 100644
index 0000000000..25efb481ed
--- /dev/null
+++ b/ml-proto/spec/floatsig.ml
@@ -0,0 +1,53 @@
+module type REP =
+sig
+  type t
+
+  val nondeterministic_nan : t 	 
+  val bits_of_float : float -> t
+  val float_of_bits : t -> float
+
+  val logand : t -> t -> t
+  val logor : t -> t -> t			   
+  val logxor : t -> t -> t
+			   
+  val min_int : t
+  val max_int : t
+
+  val size : int		  
+
+end
+
+module type FLOAT =
+sig
+  type t
+  type bits
+  val of_float : float -> t
+  val to_float : t -> float
+  val of_string : string -> t
+  val to_string : t -> string
+  val of_bits : bits -> t
+  val to_bits : t -> bits
+  val add : t -> t -> t
+  val sub : t -> t -> t
+  val mul : t -> t -> t
+  val div : t -> t -> t
+  val sqrt : t -> t
+  val min : t -> t -> t
+  val max : t -> t -> t
+  val ceil : t -> t
+  val floor : t -> t
+  val trunc : t -> t
+  val nearest : t -> t
+  val abs : t -> t
+  val neg : t -> t
+  val copysign : t -> t -> t
+  val eq : t -> t -> bool
+  val ne : t -> t -> bool
+  val lt : t -> t -> bool
+  val le : t -> t -> bool
+  val gt : t -> t -> bool
+  val ge : t -> t -> bool
+  val size : int
+  val zero: t
+end
+
diff --git a/ml-proto/spec/i32_convert.ml b/ml-proto/spec/i32_convert.ml
index 4ea0c0f772..304f6f6553 100644
--- a/ml-proto/spec/i32_convert.ml
+++ b/ml-proto/spec/i32_convert.ml
@@ -1,3 +1,6 @@
+module F32 = Values.F32
+module F64 = Values.F64
+
 (* WebAssembly-compatible type conversions to i32 implementation *)
 
 let wrap_i64 x = Int64.to_int32 x
diff --git a/ml-proto/spec/i32_convert.mli b/ml-proto/spec/i32_convert.mli
index 2737aadd22..4208ac8ef8 100644
--- a/ml-proto/spec/i32_convert.mli
+++ b/ml-proto/spec/i32_convert.mli
@@ -1,8 +1,8 @@
 (* WebAssembly-compatible type conversions to i32 implementation *)
 
 val wrap_i64 : I64.t -> I32.t
-val trunc_s_f32 : F32.t -> I32.t
-val trunc_u_f32 : F32.t -> I32.t
-val trunc_s_f64 : F64.t -> I32.t
-val trunc_u_f64 : F64.t -> I32.t
-val reinterpret_f32 : F32.t -> I32.t
+val trunc_s_f32 : Values.F32.t -> I32.t
+val trunc_u_f32 : Values.F32.t -> I32.t
+val trunc_s_f64 : Values.F64.t -> I32.t
+val trunc_u_f64 : Values.F64.t -> I32.t
+val reinterpret_f32 : Values.F32.t -> I32.t
diff --git a/ml-proto/spec/i64_convert.ml b/ml-proto/spec/i64_convert.ml
index 0cf32f8c36..02b8f7c9eb 100644
--- a/ml-proto/spec/i64_convert.ml
+++ b/ml-proto/spec/i64_convert.ml
@@ -1,3 +1,6 @@
+module F32 = Values.F32
+module F64 = Values.F64
+
 (* WebAssembly-compatible type conversions to i64 implementation *)
 
 let extend_s_i32 x = Int64.of_int32 x
diff --git a/ml-proto/spec/i64_convert.mli b/ml-proto/spec/i64_convert.mli
index 50a3b3a3ea..f8f2906f1d 100644
--- a/ml-proto/spec/i64_convert.mli
+++ b/ml-proto/spec/i64_convert.mli
@@ -2,8 +2,8 @@
 
 val extend_s_i32 : I32.t -> I64.t
 val extend_u_i32 : I32.t -> I64.t
-val trunc_s_f32 : F32.t -> I64.t
-val trunc_u_f32 : F32.t -> I64.t
-val trunc_s_f64 : F64.t -> I64.t
-val trunc_u_f64 : F64.t -> I64.t
-val reinterpret_f64 : F64.t -> I64.t
+val trunc_s_f32 : Values.F32.t -> I64.t
+val trunc_u_f32 : Values.F32.t -> I64.t
+val trunc_s_f64 : Values.F64.t -> I64.t
+val trunc_u_f64 : Values.F64.t -> I64.t
+val reinterpret_f64 : Values.F64.t -> I64.t
diff --git a/ml-proto/spec/values.ml b/ml-proto/spec/values.ml
index b941db5ca6..04fee1a4e5 100644
--- a/ml-proto/spec/values.ml
+++ b/ml-proto/spec/values.ml
@@ -10,8 +10,23 @@ open Types
 type ('i32, 'i64, 'f32, 'f64) op =
   Int32 of 'i32 | Int64 of 'i64 | Float32 of 'f32 | Float64 of 'f64
 
-type value = (I32.t, I64.t, F32.t, F64.t) op
+module F32 =
+  Float.FloatPrims(
+      struct
+	include Int32
+	let nondeterministic_nan = 0x7fc0f0f0l
+	let size = 32
+      end)
+
+module F64 =
+  Float.FloatPrims(
+      struct
+        include Int64
+        let nondeterministic_nan = 0x7fff0f0f0f0f0f0fL
+        let size = 64
+      end)
 
+type value = (I32.t, I64.t, F32.t, F64.t) op
 
 (* Typing *)