Driver for randomize operations

drivers/ocaml64.drv

@@ -224,6 +224,13 @@ module mach.int.Int63
   syntax val      of_bv     "(fun x -> x)"*)
 end
 
+module mach.int.Random63
+  syntax val init          "Random.init %1"
+  syntax val self_init     "Random.self_init"
+  syntax val random_bool   "Random.bool"
+  syntax val random_int63  "Random.int %1"
+end
+
 module mach.peano.Peano
   syntax type t      "int"
   syntax val  to_int "Z.of_int %1"

modules/mach/int.mlw

@@ -334,7 +334,7 @@ module Random63
   = random_bool s
 
   let random_int63 (n: int63) : int63
-    requires { 0 < n }
+    requires { 0 < n } (* FIXME: n should be less than 2^30 *)
     ensures  { s.state = next (old s.state) }
     ensures  { result = get_int s.state n }
     ensures  { 0 <= result < n }