open Instr;;

(** taille des pages *)
let page_size = 10;;

(** nombre de pages *)
let page_number = 100;;

(** taille de la table des pages *)
let ptable_size = page_size / 2;;

(** mémoire physique *)
let memory = Array.create (page_number * page_size) 0;;

(** exception de faute de page *)
(** avec le numéro de page fautive *)
exception Page_fault of int;;

let get ptable address =
  if address < Array.length memory then
    memory.(address)
  else
    raise Segmentation_fault;;

let set ptable address v =
  if address < Array.length memory then
    memory.(address) <- v
  else
    raise Segmentation_fault;;

let used_page () = false;;

type mode = UN | RW | COW

let int_of_mode mode =
  match mode with UN -> 0 | RW -> 1 | COW -> 2

let mode_of_int i =
  match i with 0 -> UN  | 1 -> RW | 2 -> COW | _ -> assert false;;