matitaB/matita/contribs/ng_assembly2/emulator/read_write/IP2022_fetch.ma

   1 (**************************************************************************)
   2 (*       ___                                                              *)
   3 (*      ||M||                                                             *)
   4 (*      ||A||       A project by Andrea Asperti                           *)
   5 (*      ||T||                                                             *)
   6 (*      ||I||       Developers:                                           *)
   7 (*      ||T||         The HELM team.                                      *)
   8 (*      ||A||         http://helm.cs.unibo.it                             *)
   9 (*      \   /                                                             *)
  10 (*       \ /        This file is distributed under the terms of the       *)
  11 (*        v         GNU General Public License Version 2                  *)
  12 (*                                                                        *)
  13 (**************************************************************************)
  14
  15 (* ********************************************************************** *)
  16 (*                          Progetto FreeScale                            *)
  17 (*                                                                        *)
  18 (*   Sviluppato da: Ing. Cosimo Oliboni, oliboni@cs.unibo.it              *)
  19 (*   Sviluppo: 2008-2010                                                  *)
  20 (*                                                                        *)
  21 (* ********************************************************************** *)
  22
  23 include "emulator/read_write/fetch_base.ma".
  24 include "emulator/status/status.ma".
  25
  26 (* PC word aligned *)
  27 (* PC < 0x8000 → segmento 1 program ram *)
  28 (*else         → segmento 2 program flash *)
  29 ndefinition IP2022_pc_flashtest ≝
  30 λpc:word16.getMSBc ? pc.
  31
  32 ndefinition IP2022_pc_translation ≝
  33 λpc:word16.match shlc ? pc with
  34  [ pair msb pc' ⇒ pair …
  35   match msb with [ true ⇒ o2 | false ⇒ o1 ] pc' ].
  36
  37 (* opcode a byte o 0x00 + byte : IP2022 *)
  38 (* opcode + operando a dimensione fissa 16bit *)
  39 ndefinition IP2022_fetch_byte_or_word ≝
  40 λm,t.λs:any_status m t.λpc:word16.
  41  match mem_read t (mem_desc … s) (chk_desc … s)
  42                 (fst … (IP2022_pc_translation pc))
  43                 (snd … (IP2022_pc_translation pc)) with
  44   [ None ⇒ FetchERR ? ILL_FETCH_AD
  45   | Some bh ⇒ match eqc ? bh 〈x0,x0〉 with
  46    [ true ⇒ match mem_read t (mem_desc … s) (chk_desc … s)
  47                              (fst … (IP2022_pc_translation pc))
  48                              (succc ? (snd … (IP2022_pc_translation pc))) with
  49     [ None ⇒ FetchERR ? ILL_FETCH_AD
  50     | Some bl ⇒ fetch_word_aux m (succc ? pc) 〈bh:bl〉
  51     ]
  52    | false ⇒ fetch_byte_aux m (succc ? pc) bh
  53    ]
  54   ].