 6 

 室  ࠡ  ⨧筮 ०. ।⢠    ᯮ짮  ।饭  ﭨ ६ 믮塞 . ਬ,  믮   ࠭  祩    㣮 .
 ࠧࠡ⪥ ணࠬ 堭      ⨭ ணࠬ 訡.  ணࠬ 믮  뫪  ⨬     , 堭   ஢  ᮡ⨥  ᮮ  .
 ⥬, ।祭   짮⥫ 堭   ।࠭ ⥬  ணࠬ ᡮ, 뢠 묨 訡  ணࠬ.  ᡮ  ணࠬ ⢨  ࠭ ⠪ ࠧ   ࠭祭  . 樮 ⥬  ⮬   饭  襭  ⥩,   ॣ஢ ᪮ ᮮ饭  訡  ᤥ  ⮬᪮ ⠭ ணࠬ.
  ਬ  ᥣ⠬  ࠭栬 .   ॣ  । ஢ ਢ஢ ⥪饩 믮塞 ணࠬ ( ஢ 뢠 ⥪騬 ஢ ਢ஢,  CPL).  ६ ࠭樨   㯠  ᥣ  ࠭ 믮 ஢ઠ CPL.
  몫祭 堭  ᯥ樠쭮 ࠢ饣 ॣ   ०  ।ᬮ७,   䥪  , 稢 ஢ ਢ஢ 0 ( 訩 ஢ ਢ஢) ᥬ ᥫࠬ ᥣ⮢, ਯࠬ ᥣ⮢  ⠬ ࠭筮 ⠡.

6.1   ஢ ᥣ⮢

堭   ࠭ ﭨ ࠢ쭮 ࠡ饩 ணࠬ  㣨 믮塞 ணࠬ   .  ।⠢ ᮡ 業 ᢮⢮  ࠧࠡ⪥ ணࠬ த⮢, ᪮  ᯥ稢 ࠭      । ࠧࠡ⪨ ணࠬ ᯥ祭 (樮 ⥬, ⫠稪).  ᡮ  ਪ ணࠬ   ࠢ ࠭ ணࠬ ᯥ祭, 饥 뤠 ᪨ ᮮ饭,  ⫠稪   ந "ᬥ"  ᮤন   ॣ஢ ᡮ ணࠬ.  ⥬, ᯫ ⮢ ணࠬ ᯥ祭,         樨஢ ⠭⥫ 楤  ⥬.
 뫪   ஫  窨 ७ 㤮⢮७  ஢ઠ.  ஢ન 믮  砫 横 饭  ;  襭  । 砫 横 㯠     ᪫祭. ᪮ ஢ન  믮 ࠫ쭮  ࠭樥 ,     ࠪ⨪ த⢨ ⥬.   ஢ப:

     1. ஢ઠ ⨯
     2. ஢ઠ ࠭
     3. ࠭祭 㥬 
     4. ࠭祭 祪 室  楤
     5. ࠭祭  

襭    樨 ᪫祭. 堭 ᪫祭 ᠭ   9.    ᠭ 襭  , 騥  樨 ᪫祭.
6.2 ਯ ᥣ  
 㭪 6-1   ਯ ᥣ, ᯮ㥬 堭 . ⤥      믮塞  㭪.
ࠬ    ਯ   ᮧ.  楫, ਪ ணࠬ⠬  ࠬ   ॡ.
               ਯ ᥣ 

                       2 1 1 1 1 1 1 1 1 1 1
31                     0 9 8 7 6 5 4 3 2 1 0 9 8 7            0
----------------------------------------------------------------
|               | | | | |       | | D | | | | | |              |
| BASE  31:24   | | | | |LIMIT  | | P |1|0|E|W|A|  BASE 23:16  | +4
|               | | | | |19:16  | | L | | | | | |              |
|--------------------------------------------------------------|
|       ᥣ 15:00      |    ࠭ ᥣ 15:00    | +0
----------------------------------------------------------------

               ਯ ᥣ 

                       2 1 1 1 1 1 1 1 1 1 1
31                     0 9 8 7 6 5 4 3 2 1 0 9 8 7            0
----------------------------------------------------------------
|               | | | | |       | | D | | | | | |              |
| BASE  31:24   | | | | |LIMIT  | | P |1|1|C|R|A|  BASE 23:16  | +4
|               | | | | |19:16  | | L | | | | | |              |
|--------------------------------------------------------------|
|       ᥣ 15:00      |    ࠭ ᥣ 15:00    | +0
----------------------------------------------------------------


A          ந襫
C         ଭ
DPL       ஢ ਢ஢ ਯ
E         ७ 
R         㯭  ⥭
LIMIT     ࠭ ᥣ
W         㯭  

     㭮 6-1.  ਯ, ᯮ㥬  
                         ( 1  2)


               ਯ ⥬ ᥣ

                       2 1 1 1 1 1 1 1 1 1 1
31                     0 9 8 7 6 5 4 3 2 1 0 9 8 7            0
----------------------------------------------------------------
|               | | | | |       | | D | |       |              |
| BASE  31:24   | | | | |LIMIT  | | P |0|    |  BASE 23:16  | +4
|               | | | | |19:16  | | L | |       |              |
|--------------------------------------------------------------|
|       ᥣ 15:00      |    ࠭ ᥣ 15:00    | +0
----------------------------------------------------------------


DPL       ஢ ਢ஢ ਯ
LIMIT     ࠭ ᥣ

     㭮 6-2.  ਯ, ᯮ㥬  
                         ( 2  2)

 ணࠬ 㦠  ᥣ ॣ ᥫ ᥣ,  ⮬᪨ 㦠 㤠   ⮣ ᥣ  ଠ   .    ᥣ⭮ ॣ ࠭  , ࠭, ⨯  ஢ ਢ஢.  ⮬,   ଠ १⭮ 室  ᥣ⭮ ॣ,  ᫥騥 ஢ન   ⮣ ॣ   믮  ⥫  ६   .

6.2.1 ஢ઠ ⨯

 ਯ஢  ᥣ⮢    ਪ ணࠬ,  i486  ਯ  ⥬ ᥣ⮢  .   , ᯮ㥬  ࣠樨 믮  ( 7), ⠪ ᪫祭  뢠 ( 9).   6-1 ᫥  ⨯, ।  ⥬ ᥣ⮢  . ⬥⨬,    ਯ । ᥣ: ਯ  ᮤঠ 窨 室  楤.
  ਯ஢ ᥣ⮢      ᥡ ,  ஡ ।騥 祭 ᥣ (. 㭮 6-1):
-  "㯭  "  ਯ ᥣ  ࠢ  믮   ணࠬ   ᥣ.
-  "㯭  ⥭" ਯ 믮塞 ᥣ   믮 ⥭ ணࠬ   ᥣ (ਬ  㯠  ⠭⠬, ᠭ ।⢥   ). 㯭  ⥭ 믮塞 ᥣ   ⠭  ᯮᮡ:
1.   ॣ CS, ᯮ 䨪 ८। ᥣ CS. 2.   㧪 ᥫ   ਯ  ॣ ᥣ  (DS, ES, FS  GS).

          6-1.  ⥬ ᥣ⮢  

-----------------------------------------------------------------
                                  ᠭ
-----------------------------------------------------------------
      0         ࢨ
      1         㯭 ᥣ ﭨ  (TSS) 80286
      2         LDT
      3          ᥣ ﭨ  (TSS) 80286
      4          맮
      5          
      6          뢠 80286
      7          襪 80286
      8         ࢨ
      9         㯭 TSS  i486
     10         ࢨ
     11          TSS  i486
     12          맮  i486
     13         ࢨ
     14          뢠  i486
     15            i486
-----------------------------------------------------------------

஢ઠ ⨯  ᯮ짮  । ணࠬ 訡,   ⪥ ᯮ짮 ᥣ⮢ ᯮᮡ,  ࠧ㬥訬 ணࠬ⮬.  ᬠਢ ଠ  ⨯    : 
 1.  ᥫ  ਯ 㦠  ᥣ ॣ.  ᥣ ॣ  ᮤঠ ⮫쪮  ⨯ ਯ஢; ਬ:
-  CS   㦥 ⮫쪮 ᥫ஬ 믮塞 ᥣ.
-  믮塞 ᥣ⮢,  騥 "㯭묨  ⥭",    㦥  ॣ ᥣ⮢ .
-  ॣ SS   㦥 ⮫쪮 ᥫ ᥣ⮢ , "㯭  ".
2.  ᥣ  ᯮ짮  ⮫쪮 묨, ।।묨 ᯮᮡ; ਬ:
-     믮   믮塞 ᥣ.
-     믮   ᥣ , ᫨    ⠭  "㯥  ".
-     믮 ⥭ 믮塞 ᥣ, ᫨    ⠭  "㯥  ⥭".

6.2.2 ஢ઠ ࠭

 ࠭ ਯ ᥣ   ணࠬ 믮   ᥣ. 饥 祭 ࠭   ⠭  G ( ࠭樨).  ᥣ⮢  ࠭ ⠪    E ( ࠢ ७ ᥣ).  ⢥  E 砥   ⮢    뫪  ਯࠬ ᥣ⮢ .
  G 饭, ࠭ ᥣ ࠢ 祭 20-ࠧ來  ࠭ ਯ.  ⮬ 砥 ࠭      0  0FFFFFH (2**20-1,  1 ). ᫨  G ⠭,   㬭 祭  ࠭  ⠡ 樥 2**12.  ⮬ 砥 ࠭ 㤥     0FFFH (2**12-1,  4K),  0FFFFFFFFH (2**32-1,  4 ).⬥⨬,   ᯮ짮 ⠪ ⠡஢, ஢ઠ ࠭   12 ⮢   믮;   G ⠭,  ࠭ ᥣ ࠢ 0, ⨬ 祭 ᬥ饭  ᥣ     0  4095. 
  ⨯ ᥣ⮢,  ᪫祭 ᥣ⮢, 塞
 (.. ⥪ ᥣ⮢), 祭 ࠭  
 ࠧ ᥣ  .  
᪫祭 饩     ᫥ 砥:

 - ⪠ 㯠     , ॢ饬 ࠭ ᥣ.
- ⪠ 㯠  ᫮   , ॢ饬 ࠭ ᥣ - 1.
- ⪠ 㯠   ᫮   , ॢ饬 ࠭ ᥣ 
- 3.  ᥣ⮢,  , ࠭ 㦨  ⮩  㭪樨 ஢ન,   .  ⮬ 砥  ⨬ 祭  ।  (࠭+1)  2** 32-1.   ७   ᨬ ࠧ  祭 ࠭, ࠢ 0.
஫ ࠭  ⫠ ⠪ ணࠬ 訡,  ୮ ᫥  ᨢ  ⨬ 㪠⥫.  訡 । ࠧ ,  ⮫쪮  ந諨, ⮬ 䨪 맢襩  稭 ⢥ 頥.  ⠪ ஫ ࠭ 㪠 訡   ᫥⢨ ࠧ襭  ⥩   㣨 ,   ⢮  㦨,   ந ᡮ  ᯮ祭 ⠪ ࠧ 㫥,  ⠪ ᮡ⨥  㯨  , 祬 䠪᪠ 맢  訡.   ஢ ⠪ 訡  ᮮ   筨.
   ஢થ ࠭ ᥣ⮢  ⠪ ஢ઠ ࠭ ⠡ ਯ஢.  GDTR  IDTR ᮤঠ 16-ࠧ來 祭 ࠭.  ᯮ ஬   ணࠬ  롮 ਯ ᥣ  , 饩   ⠡. ࠭ ⠡ ਯ஢  ᫥ ⨬  ⮩ ⠡. ᪮  ਯ   ᥬ ⮢, ⠡, ᮤঠ  N ਯ஢,   祭 ࠭, ࠢ 8N-1.
ਯ    㫥 祭.  ⭮  ࢮ ਯ  ⠡ GDT,   ᯮ.   ਯ   㦥  ᥣ ॣ,  ⪠ 뫪     ⮣ ਯ ਢ  樨 ᪫祭 饩 .

6.2.3 ஢ ਢ஢

堭  ᯮ  ஢ ਢ஢, 㬥㥬  0  3.   , ⥬  ஢ ਢ஢.  㤮⢮७   ஢ப  ᪫祭 饩    ⪥ ணࠬ 㯠  ᥣ  訬 ஢ ਢ஢ (..  訬 ᫮, 騬 ஢), 祬   ᥣ.
  ⬥ 堭   ࠢ饣 ॣ   ०  ।ᬮ७, ⮣  䥪  ⨣ ⥬ ᢮ ᥬ ஢ ਢ஢ 祭 0. ( PE ॣ CR0   ࠧ騬 ⮬ ᮡ⢥  堭 ;  ᯮ  祭 "饭 ०", ० 믮 ணࠬ,  ஬ 㯭   32-ࠧ來 ⥪   楫. ᫨ 饭 ० 몫祭,   ࠡ⠥  ० "ॠ ᮢ",   ॠ  饣  ᮪ த⢨  襭  8086).
஢ ਢ஢  ᯮ짮  襭  樮 ⥬.  砥 ᢮ 樮 ⥬ 襣 ஢ ਢ஢  ⠭ 饭  ᡮ  砥 訡  㣨 ணࠬ.  ⠪ ணࠬ ᡮ 樮 ⥬   ᣥ஢ ᮮ⢥騥 ᪨ ᮮ饭   믮 ⠭⥫ 楤.
騩 ஢ ਢ஢   ⠭  㣨 ⥩ ணࠬ ᯥ祭, ⠪  ணࠬ, ࠢ騥 ਩묨 ன⢠,  뢠 ࠩࠬ ன.  ᡮ  ࠩ ன⢠ 樮 ⥬    뤠 ᪮ ᮮ饭, ⮬    樮 ⥬   ᡮ ࠩ஢ ன. , ࠩ ன⢠  ࠡ   ਩ 㤮, ਬ  ᪮.  ਪ ணࠬ   ਢ  ࠧ襭  ४਩  ᪥, ⮬    ࠩ ன  ᡮ ਪ ணࠬ. ࠩ ன   ஢ ਢ஢ ஬,  樮 ⥬  ਪ묨 ணࠬ. ਪ ணࠬ ᢠ ᠬ  ஢ ਢ஢.
 㭪 6-2 ,   ஢ ਢ஢   ஢  ⢥  . ࠫ쭮   ᮤন ᥣ,   室   ணࠬ ᯥ祭, 筮  樮 ⥬. 稥  ᯮ    ணࠬ ᯥ祭.
஢ ਢ஢ ࠭  ᫥  :
-    ᥣ⭮ ॣ CS ᮤঠ ⥪騩 ஢ ਢ஢ (CPL).  ஢ ਢ஢ 믮塞  ⥪騩  ணࠬ. 訥   ॣ SS ⠪ ᮤঠ  CPL. 筮 CPL ࠢ ஢ ਢ஢  ᥣ,  ண ந室 롮ઠ  ணࠬ. CPL   । ࠢ  ᥣ  㣨 ஢ ਢ஢.
- ਯ ᥣ ᮤঠ , ஥ 뢠 ஢ ਢ஢ ਯ (DPL). DPL ।⠢ ᮡ ஢ ਢ஢ ਬ⥫쭮  ᥣ.
-  ᥣ ᮤঠ , ஥ 뢠 襭 ஢ ਢ஢ (RPL) RPL ।⠢ ᮡ ஢ ਢ஢ 楤, ᮧ襩  ᥫ. ᫨ RPL  訩 ஢ ਢ஢, 祬 CPL,   頥 CPL.   ਢ஢ ணࠬ ਭ ᥫ ᥣ   ਢ஢ ணࠬ, RPL 뢠     訬 ஢ ਢ஢.
஢ ਢ஢ ஢,  ᥫ ਯ 㦠  ᥣ ॣ. ஢ન, ᯮ㥬  㯠  , ⫨  ஢ப  । 믮  믮塞묨 ᥣ⠬; ᫥⥫쭮,   ⨯ 㯠, ᬠਢ  ᫥ ࠧ  ⤥쭮.

                         
                             **
                         *        *
                             **
                    *    *        *    *
                             **
                  *   *   *      *   *    *

           *   *   *     * *     *   *   *
樮 -----------> *      *
⥬       *   *   *  *஢ 0*  *  *  *
                          *      *
               *   *   *     * *     *  *   *
ᯮ⥫ --------> ஢ 1
।⢠                 *         *
樮      *   *       **       *   *
⥬ (ࠩ ------> ஢ 2
ன  ..)   *    *         *     *
                              **
ਪ ணࠬ----> ஢ 3
                         *         *
                              **

                   㭮 6-2.  

6.3 ࠭祭 㯠  

 樨 ࠭   ᥫ ᥣ    㦥  ॣ ᥣ  (ॣ DS, ES, FS, GS  SS).  ஢ ஢ ਢ஢ ᥣ⮢. ஢ઠ 믮  㧪 ᥫ ᥣ.    㭪 6-3,  ஢થ ਢ஢ ⮣ ⨯   ࠧ ஢ ਢ஢.
 ஢塞 ஢ ਢ஢: 
1. CPL (⥪騩 ஢ ਢ஢ ணࠬ). 
   ࠭     ॣ CS.
2. DPL (஢ ਢ஢ ਯ) ਯ
   ᥣ, ᮤঠ饣 ࠭.
3. RPL (஢ ਢ஢ 筨 ) 
   ᥫ, ᯮ㥬   ᥣ, ᮤঠ饣
   ࠭.  ஢ ࠭    
   ᥣ⭮ ॣ, ᯮ㥬  㯠  ࠭
   (ॣ SS, DS, ES, FS  GS). ᫨ ࠭ 室 
   ⥪ ᥣ,  RPL  CPL ᮢ.

               ਯ ᥣ, ᮤঠ饣 ࠭

                                   1 1
31                                 4 3           7            0
----------------------------------------------------------------
|               | | | | |       | | D | | | | | |              |
|               | | | | |       | | P | | | | | |              | +4
|               | | | | |       | | L | | | | | |              |
|--------------------------------------------------------------|
|                               |   |__________________        | +0
-------------------------------------------------------|--------
                                                       |
                騩  ᥣ ॣ     |
                                                       |
--------------------                                   |
|            | CPL |------------------------------     |
--------------------                              |    |
                 ᥣ, ᮤঠ饣    |    |
--------------------               ࠭        |    |
|            | RPL |-------------------------     |    |
--------------------                         |    |    |
                                             |    |    |
                                             \/   \/   \/
                                         ---------------------
                                         |      ஢ઠ     |
                                         |ਢ஢|
                                         ---------------------
CPL       騩 ஢ ਢ஢
DPL       ஢ ਢ஢ ਯ
RPL       襭 ஢ ਢ஢

 㭮 6-3. ஢ઠ ਢ஢  㯥  

  㦠 ᥣ ॣ ⮫쪮 ᫨ DPL ᥣ  ⠪   訩 ஢ ਢ஢ (訩  ਢ஢), 祬   ਢ஢ CPL  RPL ᥫ.
㥬       CPL. ᫨ CPL ࠢ 0,  ᥣ   ஢ ਢ஢ 㯭;  CPL ࠢ 1,  㯭 ⮫쪮 ᥣ   ஢ﬨ ਢ஢  1  3;   CPL ࠢ 3,  㯭 ⮫쪮 ᥣ   ஢ ਢ஢ 3. 
     ᥣ
  ⥫ ࠭    ᥣ; ਬ,   ,   ࠭  .  ᥣ  ᪠ ࠭ ⠬ ⠭,  믮   ᥣ, ।  ⢥  ᥣ, ⨬, ᫨  ⮬  ᭮ ࠭⢥  ⮡ࠦ ᥣ .  ᫥騥 ᯮᮡ 㯠     ᥣ: 
1. 㧪  ॣ ᥣ  ᥫ ଭ,
   㯭  ⥭ 믮塞 ᥣ.

2. 㧪  ॣ ᥣ  ᥫ ଭ,
   㯭  ⥭ 믮塞 ᥣ.

3. ᯮ짮 䨪 ८। ᥣ  ⥭ 
   㯭  ⥭ 믮塞 ᥣ, ᥫ
   ண 㦥 㦥  ॣ CS.

  1 ਬ   ࠢ 㯠,    ᥣ . 砩 2 ⨬ ᥣ, ᪮ ஢ ਢ஢  ᥣ  ⠭ ⮬ ଭ ⠪ ,   CPL, ᨬ   DPL. 砩 3 ⠪ ⨬ ᥣ, ᪮ DPL  ᥣ, ࠭   ॣ CS, ᮢ  CPL.

6.4 ࠭祭 । ࠢ

  i486 । ࠢ 믮  JMP, CALL, RET, INT  IRET,  ⠪ 堭 ᪫祭  뢠. ᪫祭  뢠 -  ᮡ 砨   ᬠਢ   9.     㦤 ⮫쪮  JMP, CALL  RET.
""   JMP, CALL  RET । ࠢ  । ᮤঠ饣   ᥣ,  ᫥⥫쭮,  ⮫쪮 ஢ન ࠭ 室.  ஢, ⮡  祭  JMP, CALL  RET  室  ࠭ ⥪饣 ᥣ . ࠭   ॣ CS, ⮬ ஢ઠ ࠭   室  ॡ ⥫  ६.
࠭ "쭨"   JMP  CALL 뫠  㣨 ᥣ, ⮬  믮 ஢ ਢ஢.   ᯮᮡ 뫪   JMP  CALL  㣨 ᥣ: 
1. ࠭ 롨ࠥ ਯ 㣮 믮塞 ᥣ.

2. ࠭ 롨ࠥ ਯ  맮.  ଠ
   । ࠢ  ᯮ짮 
   ᬠਢ   7.

   㭪 6-4,  ࠧ ஢
ਢ஢ 뢠 ஢ ਢ஢
। ࠢ  ᯮ짮  맮:

1. CPL (⥪騩 ஢ ਢ஢).

2. DPL ਯ  ᥣ 祭 室.

筮 CPL ࠢ DPL ᥣ, 믮塞 ஬  ⥪騩 . CPL  , ,  (..  ਢ஢), 祬 DPL, ᫨ ⥪騩  ᥣ  ଭ ᥣ⮬ (ଭ 㪠뢠    ᥣ⭮ ਯ). ଭ ᥣ 믮  ஢ ਢ஢ 뢠饩 楤.   ६  CPL  ॣ CS;  祭   ⫨  祭 DPL  ᥣ⭮ ਯ ⥪饣  ᥣ. 


               ਯ  ᥣ 祭 室

                                 1 1 1 1 1 1
31                               5 4 3 2 1 0 9 8 7            0
----------------------------------------------------------------
|               | | | | |       | | D |      |              |
|               | | | | |       | | P | | | | | |              | +4
|               | | | | |       | | L |1|1|C|R|A|              |
|--------------------------------------------------------------|
|                               |   |      |___________        |
|                               |   |_____________     |       | +0
--------------------------------------------------|----|--------
                                                  |    |
            騩  ᥣ ॣ    |    |
                                                  |    |
--------------------                              |    |
|            | CPL |--------------------------    |    |
--------------------                         |    |    |
                                             |    |    |
                                             \/   \/   \/
                                         ---------------------
                                         |      ஢ઠ     |
                                         |ਢ஢|
                                         ---------------------
C          ଭ
CPL       騩 ஢ ਢ஢
DPL       ஢ ਢ஢ ਯ

 㭮 6-4. ஢ઠ ਢ஢  । ࠢ  

 ࠧ蠥 । ࠢ  JMP  CALL   㣮 ᥣ ⮫쪮  ⮬ 砥, ᫨ 믮 ᫥騥 ࠢ ਢ஢:
- DPL ᥣ ࠢ ⥪饬 CPL.
-   ଭ  ᥣ⮬,   DPL  (ਢ஢ ), 祬 ⥪騩 CPL.

ଭ ᥣ ᯮ  ⠪ ணࠬ,  ⥪ ⥬᪨ 㭪権    ࠡ稪 뢠,  ন ਪ ணࠬ,   ॡ 㯠  饭 ⥬ ।⢠.  । ࠢ ଭ ᥣ CPL  ,  ᫨ ᥫ, ᯮ짮  樨 ᥣ,  㣮 RPL.  ⢥ ᫮,  CPL   ⫨  DPL ⥪饣  ᥣ.
設⢮  ᥣ⮢  -ଭ묨.  ⠪ ᥣ⮢ ࠢ  ।   ⮫쪮  㣨  ᥣ⠬, 騬   ஢ ਢ஢. ,  뢠 室 । ࠢ ᥣ⠬  訬 ஢ﬨ ਢ஢.  믮    CALL, ᯮ饩 ਯ  맮,  ᬠਢ   7.  JMP    । ࠢ -ଭ ᥣ⠬, DPL   ࠢ CPL. 

6.5   ਯ

 ᯥ祭   । ࠢ  믮塞묨 ᥣ⠬  ࠧ묨 ஢ﬨ ਢ஢  i486 ᯮ  ਯ.   ⨯  ਯ஢: 
-  맮
-  誨
-  뢠
-  

  ᯮ  ४祭   뢠   7.   9 ,   襪  뢠 ᯮ  ࠡ⪨ ᪫祭  뢠.    ᬠਢ ⮫쪮  맮.  맮 ।⠢ ᮡ   饭 । ࠢ.  ᯮ  । ࠢ  ࠧ묨 ஢ﬨ ਢ஢.  ᯮ짮 室 ⮫쪮  ⥬,     ஢ ਢ஢.  㭮 6-5  ଠ  맮. 
 맮   ᭮ 㭪樨:
1. । 窨 室  楤.
2.  ஢ ਢ஢, ॡ㥬  室  楤.


                   32-⮢  맮

31                          6 5 4 3 2 1 0 9 8 7 6 5 4 3       3
----------------------------------------------------------------
|                            | | D | | | | | | | | | |稪  |
| 饭  ᥣ  31:16 |P| P |0|1|1|0|0|0|0|0|0|  |+4
|                            | | L | | | | | | | | | |᫮     |
|                            | |   | | | | | | | | | |         |
----------------------------------------------------------------
|    ᥣ        |     饭  ᥣ 15:00   |+0
----------------------------------------------------------------

DPL    ஢ ਢ஢ ਯ
P      ⢨ ᥣ

                   㭮 6-5.   맮

ਯ  맮 ᯮ  CALL  JUMP ᯮ  ᯮᮡ,   ਯ  ᥣ⮢.  ⭠  ᯮ,  ᥫ ᥣ 祭 뫠   ਯ, 믮  । ᮤন  맮. ਯ  맮  室  GDT   LDT,    ⠡ ਯ஢ 뢠 (IDT).
   饭   ࠧ 㪠⥫   室  楤.  맮 ࠭,   । ࠢ 㣨 ᥣ⠬  ந室  ࠢ 窨 室 楤,   㤠-  । 楤 (,   㦥,  । ). ࠭  । ࠢ   ᥫ஬ ᥣ  ᬥ饭  ᥣ 窨 室  楤.  ⮣ ᥫ ᥣ 㪠뢠   ᥫ,  ᬥ饭  ᯮ.  ଠ 樨   㭪 6-6. 

|<----------------  祭 --------------->|

15           0     31                              0
---------------    ----------------------------------
|     |    |    饭  ᥣ         |
---------------    ----------------------------------
         \                         |
          \                        \/
           \                  ᯮ
            \
             \
              \            ਯ஢
               \   ----------------------------------
                \  |        |       |       |       |
                 \ |--------------------------------|
                  \|                |               |
                   |--------------------------------|
  -----------------|    饭    |  DPL  |稪| ਯ
  |                |--------------------------------| 
  |      ----------|        |  饭     |
  |      |         |--------------------------------|
  |      |         |        |       |       |       |
  |      |         |--------------------------------|
  |      |         |                |               |
  |      |-----    |--------------------------------|
  |            \   |        |       |       |       |
  |             \  |--------------------------------|
  |              \ |                |               |
  |               \|--------------------------------| ਯ
  |                |    |       |  DPL  |   | 
-----              |--------------------------------| ᥣ
| + |<------------ |            |               |
-----              |--------------------------------|
  |                |        |       |       |       |
  |                |--------------------------------|
  \/               |                |               |
窠 室        ----------------------------------
 楤

              㭮 6-6. 堭  맮

   㭪 6-7,  ஢ન ⨬ । ࠢ १  맮 ᯮ  ࠧ ஢ ਢ஢. 
஢ ਢ஢, ஢塞  । ࠢ १  맮, : 
1. CPL (⥪騩 ஢ ਢ஢).
2. RPL (஢ ਢ஢ 筨 ) ᥫ ᥣ,   ᯮ짮    맮.
3. DPL (஢ ਢ஢ ਯ) ਯ .
4. DPL ਯ ᥣ  ᥣ 祭 室.

 DPL ਯ  ।,   ஢ ਢ஢  ᯮ짮  .   ᥣ  ᮤঠ ᪮쪮 ࠧ 楤, ।祭  ᯮ짮  ࠧ ஢ ਢ஢. , 樮 ⥬    㦭 楤, ᯮ㥬  ਪ묨 ணࠬ, ⠪  ᠬ 樮 ⥬, ਬ, ணࠬ /뢮 ᨬ, ⮣  㣨 㦥 楤   ।祭 ⮫쪮  ᯮ짮  樮 ⥬, ਬ, ணࠬ 樠樨 ࠩ஢ ன.
  ᯮ짮  । ࠢ    ਢ஢ ஢, ⠪     ஢ ਢ஢ (  ᫥ 砥  ᯮ짮  易⥫쭮).  । ࠢ   ਢ஢ ஢   ᯮ짮 ⮫쪮  CALL.  JMP  ᯮ짮  ⮫쪮  । ࠢ   ᥣ  ⥬  ஢ ਢ஢,  ଭ  ᥣ  ⥬    ᮪ ஢ ਢ஢.

  室 JMP  ଭ ᥣ  㤮⢮ ᫥騥  ࠢ ਢ஢ ( ⨢ 砥  ᪫祭 饩 ): 
MAX(CPL,RPL) <= DPL  DPL  ᥣ 祭 = CPL

  CALL (  室 JMP  ଭ ᥣ)  㤮⢮ ᫥騥  ࠢ ਢ஢ ( ⨢ 砥  ᪫祭 饩 ):
MAX(CPL,RPL) <= DPL  DPL  ᥣ 祭 <= CPL 

6.5.1  ४祭 ⥪

 맮 楤  ਢ஢ ஢ 믮 ᫥饥: 
1.  CPL.
2. । ࠢ (믮).
3. ந室 ४祭 ⥪.

                맮

31                               15              7            0
----------------------------------------------------------------
|                               | | D |         |     |        |
|                               | | P |         |     |        | +4
|                               | | L |         |     |        |
|--------------------------------------------------------------|
|                               |   |__________________        | +0
-------------------------------------------------------|--------
                                                       |
                                                       |
               ਯ ᥣ  祭     |
                                                       |
                                                       |
31                               15              7     |      0
-------------------------------------------------------|--------
|               | | | | |       | | D |         |      |       |
|               | | | | |       | | P |         |      |       | +4
|               | | | | |       | | L |         |      |       |
|------------------------------------------------------|-------|
|                               |   |_______________   |       | +0
----------------------------------------------------|--|--------
                                                    |  |
                騩 ॣ  ᥣ   |  |
                                                    |  |
--------------------                                |  |
|            | CPL |-----------------------------   |  |
--------------------                            |   |  |
                  맮           |   |  |
--------------------                            |   |  |
|            | RPL |-------------------------   |   |  |
--------------------                         |  |   |  |
                                             |  |   |  |
                                             \/ \/  \/ \/
                                         ---------------------
                                         |      ஢ઠ     |
                                         |ਢ஢|
                                         ---------------------
CPL       騩 ஢ ਢ஢
DPL       ஢ ਢ஢ ਯ
RPL       襭 ஢ ਢ஢

         㭮 6-7. ஢ઠ ਢ஢ 
          । ࠢ    맮

७   (஢ ਢ஢ 0, 1  2)  ᢮ ᮡ⢥ ⥪  ਥ 맮   ਢ஢ ஢. ᫨ ⥪  뫠 ᯥ 뢠 楤,  ⥪  ᫨誮 ,   १ 筮 ࠧ ⥪  ந ᡮ 뢠 楤. ⮬ ᯥ稢   ਢ஢ ணࠬ  ᡮ ᫥⢨  ਢ஢ ணࠬ ⥬ ᮧ  ⥪  맮  ਢ஢묨 楤ࠬ  ਢ஢.   ⥪, ࠬ 맮   ண ⥪  ,  祭 ॣ஢ ࠭, ᫥ 祣 த 筮 믮 맢 楤.    ⮩ 楤 ᮤন ࠭ ॣ஢ ⠭  室 ⥪.  ᠭ 堭 ४祭  ਢ   7.
 室   ᮧ  ⥪   ᥣ ﭨ  (TSS),    㭪 6-8.    ᮡ⢥ TSS. TSS ᮤন 室 㪠⥫ ⥪  ७  . 樮 ⥬ ⢥砥  ᮧ  TSS  樠 ᮮ⢥  㪠⥫ ⥪. 室 㪠⥫ ⥪ ⮨  ᥫ ᥣ  室 祭 ॣ ESP (室 ᬥ饭  ᥣ). 室 㪠⥫ ⥪ ।⠢ ᮡ 祭, ।祭 ᪫⥫쭮  ⥭.      ६ 믮 .  㪠⥫ ⥪ ᯮ ⮫쪮  ᮧ  ⥪  믮 맮 楤   ᮪ ஢ ਢ஢.    맢 楤  ⥪ 祧.  ᫥饬 맮 楤 ந室 ᮧ  ⥪  ᯮ짮  ⮣ 室 㪠⥫ ⥪. 

          32-ࠧ來 ᥣ ﭨ 
31                                                 0
----------------------------------------------------
|                                                  | 64
|                                                  |
|                                                  |
|                                                  |
|                                                  |
|--------------------------------------------------|
|                         |         SS2            | 18
|--------------------------------------------------|
|                        ESP2                      | 14
|--------------------------------------------------|
|                         |         SS1            | 10
|--------------------------------------------------|
|                        ESP1                      | 0C
|--------------------------------------------------|
|                         |         SS0            | 8
|--------------------------------------------------|
|                        ESP0                      | 4
|--------------------------------------------------|
|                         |         SS2            | 0
----------------------------------------------------

ਬ砭:   ਢ  ⭠筮 ଠ

     㭮 6-8. 室 㪠⥫ ⥪  TSS

 ᯮ짮  맮   ஢ ਢ஢  ⥪ ᮧ 㧪   TSS.  ᯮ DPL  ᥣ 祭 ( CPL)  롮 室 㪠⥫ ⥪  ஢ ਢ஢ 0, 1  2.
DPL  ⥪ ᥣ   ࠢ  CPL:  ⨢ 砥  ᪫祭 ᡮ  ⥪. ⢥⢥  ᮧ ⥪  ਯ஢ ⥪ ᥣ   ᯮ㥬 ஢ ਢ஢   樮 ⥬. ⥪   㯭  ⥭/,      ᮮ⢥ ᥣ ਯ஢.   ᮤঠ 筮 ,    ࠭, ⮡ ⠬   ᮤন ॣ஢ SS  ESP,  , ࠬ  ६ ६, ॡ㥬  ࠡ 뢠 楤.
   맮  ।  ஢ ਢ஢, ࠬ   楤   ⥪. ⥬  ࠬ    ⥪.   ⨬ ࠬࠬ  뢠 楤 ந室  ⥬  ᠬ,    ࠬ 室   ४祭 ⥪.  稪  맮 ᮮ頥 , ᪮쪮  ᫮ ( 31)  ஢  ⥪ 뢠饩 楤  ⥪ 뢠 楤. ᫨  稪 ࠢ 0,  ஢ ࠬ஢  ந室.
᫨ ॡ ।  뢠 楤  31  ᫮ ,    ࠬ஢  ᤥ 㪠⥫   ,  ࠭   祭 ॣ஢ SS  ESP  ᯮ짮  㯠  ࠬࠬ  ன  ⥪.
 ६ 맮 楤  㣨 ஢ ਢ஢  믮 ᫥騥 易  ⥪ ⢨: 
1. ஢ ⥪ 뢠 楤, ⮡ 㡥,   筮   ⮣, ⮡ ࠭ ࠬ  ࠭塞 祭 ॣ஢;  ⨢ 砥  ᪫祭 ९ ⥪.
2. ஥ ᮤন ॣ஢ SS  ESP 頥  ⥪ 뢠 楤     ᫮ (16-ࠧ來 ॣ SS  㫥  32 ⮢;   㫥 襥 ᫮ १ࢨ஢ Intel  ७ 짮;   ᯮ짮).
 3. ࠬ   ⥪ 뢠饩 ணࠬ  ⥪ 뢠 ணࠬ.
4.   ⥪ 頥 㪠⥫ , 室饩 ᫥  CALL (஥ ᮤন ॣ஢ CS  IP). ন ॣ஢ SS  ESP ᫥ 맮 㪠뢠   㪠⥫    ⥪.

 㭪 6-9   ⥪ ,  ६  ᫥ ᯥ譮 맮    楤ࠬ  ࠧ묨 ஢ﬨ ਢ஢.
TSS   㪠⥫ ⥪  ⥪  ஢ ਢ஢ 3, ᪮ 楤  ஢ ਢ஢ 3    맢 楤ன     ஢. ⥪  ஢ ਢ஢ 3 ।࠭ ᮤন ॣ஢ SS  EIP,  ࠭  ⥪ ਢ஢ ஢, 맢  ஢ 3. 

   ⥪          ⥪            ⥪
   맮           ᫥ 맮,        ᫥ 
                       

                      ----------------
|             |       |  SS    |     |             |
|-------------|       |--------------|     |-------------|
|             |       |  ESP   |     |             |<-ESP
|-------------|       |--------------|     |-------------|
| ࠬ 1  |       | ࠬ 1   |     |             |
|-------------|       |--------------|     |-------------|
| ࠬ 2  |       | ࠬ 2   |     |             |
|-------------|       |--------------|     |-------------|
| ࠬ 3  |<-ESP  | ࠬ 3   |     |             |
|-------------|       |--------------|     |-------------|
|             |       |  CS    |     |             |
|-------------|       |--------------|     |-------------|
                      |  EIP   |<-ESP
                      |--------------|
                      |              |
                      |--------------|

         㭮 6-9.  ⥪  맮 楤
               㣨 ஢ ਢ஢

맮, ᯮ騩  맮,  ஢ 祭 ᫮, 㥬   ⥪. 맢 楤  ஢ ⨬  ࠬ.  ᫥ ࠧ 㦤 ᯮ짮  ARPL, VERR, VERW, LSL  LAR  ஢ન 祭 㪠⥫. 

6.5.2    楤

""   RET 믮 । ࠢ ⮫쪮  । ⥪饣  ᥣ,  ᫥⥫쭮,   믮 ⮫쪮 ஫ ࠭. 饭  , ᫥饩 ᫥  맮 CALL,   ⥪  頥  ॣ EIP.  ஫, ⮡  ᬥ饭  ॢ室 ࠭ ⥪饣  ᥣ.
"" ଠ  RET   , 饭  ⥪ ।饩  CALL.  ଠ ᫮ 㪠⥫  ᥣ ⮢७, ᪮   ᣥ஢  CALL  INT.   ,  믮 ஢ ਢ஢ ᫥⢨  ⮣,  ⥪ 楤  㪠⥫   ᬮ ࠢ쭮 ࠡ ⥪. RPL ᥫ  ᥣ, 祭  ⥪  ,   ஢ ਢ஢ 뢠饩 楤.
  㣮 ᥣ   ஢ ਢ஢,  ⮫쪮  ஭   ஢.   RET 砥 ࠭ 祭 CS, RPL ண ᫥  CPL (..   ਢ஢ ஢), ந室  १ ஢ ਢ஢.  த  믮 ᫥騥 蠣: 
1. 믮 ஢ન,    6-2  ॣ CS, EIP, SS  ESP 㦠  ।騬 祭ﬨ,  뫨 ࠭  ⥪.

2. ஥ ᮤন ॣ஢ SS  ESP ( 設 ⥪饣 ⥪) ࠨ  ࠧ  ,    RET. 饥 祭 ESP  ஢  ࠭ ⥪ ᥣ. ᫨ 祭 ESP 室   ࠭,   䠪  ᯮ ஬  ᫥饩 ⥪ 樨. (ন ॣ஢ SS  ESP  頥 楤  ࠭; 筮  祭  ,   ࠭  TSS).

3. ஢ ᮤন ᥣ ॣ஢ DS, ES, FS  GS. ᫨     ॣ஢ 뫠  ᥣ, DPL ண   CPL ( ଭ  ᥣ), ᥣ ॣ 㦠  ᥫ஬ (=0, TI=0).   RET  ⠪   ᮮ頥  ᪫祭;   ᫥騥 뫪     ᥣ⭮ ॣ, ᮤয饣 ⮩ ᥫ, 맮 ᪫祭 饩 .     ਢ஢     ਢ஢ ᥣ⠬ ।⢮ ᥫ஢, ⠢  ᥣ ॣ  ਢ஢ 楤ன.

       6-2. ஢ન    楤ࠬ
              ࠧ묨 ஢ﬨ ਢ஢

------------------------------------------------------------------
| ஢ન |                   ᮡ 樨 |  訡|
------------------------------------------------------------------
|設 ⥪                                         |
| । ࠭ ᥣ                                     |
|⥪                            ⥪                 0         |
|                                                                |
| 設 ⥪+7                                 |
| । ࠭ ᥣ                                     |
|⥪                            ⥪                 0         |
|                                                                |
|RPL  ᥣ                                   |
| ॢ CPL                           CS |
|                                                                |
|  ᥣ                                      |
|                     CS |
|                                                                |
|ਯ  ᥣ                                    |
|    ।                                 |
|࠭ ⠡ ਯ஢                   CS |
|                                                                |
|ਯ ᥣ                                     |
| ⭮                                      |
|ᥣ                                       CS |
|                                                                |
|⢨  ᥣ                          |
|                                 CS |
|                                                                |
|DPL -ଭ                                      |
|ᥣ                                      |
|ࠢ RPL ᥫ                                     |
|ᥣ ,  DPL                                     |
|ଭ  ᥣ                                   |
|                                        |
| ࠢ RPL ᥫ                                 |
|ᥣ                               CS |
|                                                                |
|ESP+N+15*   室                                    |
| । ࠭ ᥣ                                     |
|⥪                              ⥪        CS |
|                                                                |
| ᥣ  ESP+N+12*                                   |
|                             CS |
|                                                                |
|ਯ ᥣ  ESP+N+12*                                 |
| 室  ।                                    |
|࠭ ⠡ ਯ஢                   CS |
|                                                                |
|ਯ ⥪ ᥣ                                   |
|  㯥                                         |
|⥭/                                  CS |
|                                                                |
| ⢮ ⥪                                  |
|ᥣ                            ⥪        CS |
|                                                                |
|DPL ண ⥪ ᥣ                                  |
|  ࠢ RPL ண                                   |
| ᥣ                              CS |
|                                                                |
| ண ⥪                                      |
|ᥣ   RPL,                                      |
|ࠢ DPL ண ⥪                                    |
|ᥣ                                       CS ᥣ|
------------------------------------------------------------------

* N -  祭 ।⢥ ࠭,    RET. 

6.6  , १ࢨ஢  ࠡ 樮 ⥬

,   ⢮  堭     騥 ࠪ⨪ ந⥫쭮 ⥬,  믮 ⮫쪮  ஢७묨 楤ࠬ.  i486    ⠪ : 
1. ਢ஢  - , ᯮ㥬  ࠢ ⥬.
2. ⢨⥫  - , ᯮ㥬  / 뢮  ⢨, 易  /뢮. 

6.6.1  ਢ஢ 

,  뢠 ﭨ  ।⢠  ⥬,   믮 ⮫쪮  CPL ࠢ 0 (訩 ஢ ਢ஢). ᫨ -    믮  CPL  ࠢ 0,  ᪫祭 饩 .  ᫮   室: 
CLTS               -  䫠 ४祭 
HLT                - 믮 ⠭ 
LGDT               - 㧨 ॣ GDT
LIDT               - 㧨 ॣ IDT
LLDT               - 㧨 ॣ LDT
LMSW               - 㧨 ᫮ ﭨ 設
LTR                - 㧨 ॣ 
MOV / CR0       - 뫪  ࠢ騬 ॣ஬ 0
MOV / DRn       - 뫪  ⫠ ॣ஬ n
MOV / TRn       - 뫪  ⮢ ॣ஬ n

6.6.2  ⢨⥫ 

, ࠡ騥  /뢮,   饭묨,   ⠪    믮    ஢ ਢ஢,  ࠢ 0 (. 믮     ਢ஢ ஢). 堭  権 /뢮 ஡ ᠭ   8. 

6.6   ஢ન ⮢୮ 㪠⥫

஢ઠ ⮢୮ 㪠⥫ 室  ঠ ஢ ࠧ ஢ ਢ஢.  ⮨  ᫥ 蠣: 
1. ஢ઠ ⮣,  楤, ᮧ  㪠⥫,  ࠢ 㯠   ᥣ.
2. ஢ઠ ⮣,  ⨯ ᥣ ᮢ⨬  襭 ᯮᮡ  ᯮ짮.
3. ஢ઠ ⮣,  ᬥ饭 㪠⥫  ॢ蠥 ࠭ ᥣ.

  i486 ⮬᪨ 믮 ஢ન 2  3  믮 ,  믮 ࢮ ஢ન  ⢮ ணࠬ ᯥ祭.  ⮣ ।祭  ARPL. ணࠬ ᯥ祭  ⠪ 믮 ஢ન 2  3  ,  㤥 ᣥ஢ ᪫祭 .  ⮣ ।祭  LAR, LSL, VERR  VERW.
 ० 짮⥫  믮 ⥫쭠 ஢ઠ ࠢ.  ६ ⠭  AM ॣ CR0  䫠 AC, ࠢ 뫪     樨 ᪫祭.  ᢮⢮   ணࠬ,  ᯮ  訥  㪠⥫  䨪樨 ⨯  㥬 㪠⥫ . ਬ, ணࠬ  ⥪ ⥬᪨ 㭪権  ਭ 㪠⥫  ᫮  . ᫨ ⨯ ⠪  ᢮  10 (), ᠭ     㪠⥫   ⨯,  ⥬᪨ ணࠬ  믮 ४   ⨯, ਡ ᬥ饭 -10 (筮).  祭 ணࠬ ୮ 㪠⥫ ⨯ 뫪 㤥 ࠢ,  ਢ  樨 ᪫祭. ஢ઠ ࠢ ᪮ ࠡ ணࠬ, ᠭ  몠 ⢥ ⥫, ⠪  Lisp, Prolog, Smalltalk  C++.  ⠪  ᯮ짮  ᪮७ ஢ન ਧ ⨯ 㪠⥫.
LAR (㧨 ࠢ 㯠) ᯮ  䨪樨 ⮣,  㪠⥫ 뫠  ᥣ  ᮢ⨬  ஢ ਢ஢  ⨯.  LAR   ࠭ - ᥫ ᥣ  ਯ, ࠢ 㯠 ண   ஢७. ਯ ᥣ   㯭  ⥭  ஢ ਢ஢, ᫥ 襬 (..  ਢ஢), 祬 CPL  RPL ᥫ. ᫨ ਯ 㯥  ⥭,   LAR ਭ ஥  ᫮ ਯ, ᪨  祭 00FxFF00H, 뢠 १   32-ࠧ來 ॣ 祭  ⠭ 䫠 ZF. (x 砥,  ᮮ⢥騥   ᠭ 祭 ।).   㦥, ஢ 㯠   ⥬ ஢७.  LAR  ஢  ⨬몥 ⨯ ਯ஢. ᫨ RPL  CPL ॢ蠥 DPL,  ᫨ ᥫ ᥣ ॢ蠥 ࠭  ⠡ ਯ஢, ࠢ 㯠  ,  䫠 ZF 頥. 
LSL (㧨 ࠭ ᥣ)  ணࠬ ஢ ࠭ ਯ ᥣ, ᫨ ਯ,   뫠 ᥫ ᥣ (    ॣ), 㯥  ⥭  ⥪饬 CPL.  LSL 㦠  32-ࠧ來 ॣ 32-ࠧ來 ࠭㫨஢ ⭮ 祭 ࠭, ᫥  ᭮ ⥭஢  ࠭   ࠭樨 G ਯ.    ᤥ ⮫쪮  ਯ஢, 뢠 ᥣ (, , ﭨ   ⠡ ਯ஢); ਯ  ⠪ ᯮᮡ 㯭. ( ⠡ 6-3 ஡ ᫥,  ⨯ ⨬,   ).  ࠭   ⨯ ᥣ. ਬ, ᥣ , 騥  (⥪ ᥣ) ᬠਢ ࠭ , 祬  稥 ⨯ ᥣ⮢.   , LAR  LSL, 䫠 ZF ⠭  ⮬ 砥, ᫨ 㧪 뫠 믮 ᯥ譮;  ⨢ 砥 䫠 ZF 頥. 

      6-3. ⨬ ⨯ ਯ஢  LSL
-----------------------------------------------------------------
 ⨯              ਯ                  ⨬?
-----------------------------------------------------------------
   0                 १ࢨ஢                   
   1                 १ࢨ஢                   
   2                 LDT                              
   3                 १ࢨ஢                   
   4                 १ࢨ஢                   
   5                                        
   6                 १ࢨ஢                   
   7                 १ࢨ஢                   
   8                 १ࢨ஢                   
   9                 㯥 TSS 業ࠫ쭮
                      i486                  
   A                 १ࢨ஢                   
   B                  TSS 業ࠫ쭮
                      i486                  
                     맮 業ࠫ쭮
                      i486                  
   D                 १ࢨ஢                   
   E                  뢠 業ࠫ쭮
                      i486                  
                     誨 業ࠫ쭮
                      i486                  
-----------------------------------------------------------------

6.7.1  ஢ઠ ⮢୮ ਯ

 i486   , VERR  VERW,  ।, 㪠뢠  ᥫ ᥣ  ᥣ,  㯥  ⥭    ⥪饣 CPL.       뢠 ⭮ ᪫祭, ᫨ ᥣ 㯥. 
VERR (䨪 㯭 ⥭) 믮 䨪 㯭 ᥣ  ⥭  ⠭ 䫠 ZF, ᫨  ⥪饣 CPL  ᥣ 㯥  ⥭.  VERR ஢ ᫥饥: 
-  ᥣ 㪠뢠  ਯ ᥣ  । ࠭ GDT  LDT.
-  ᥣ  ਯ ᥣ   .
-  㯥  ⥭   ᮢ⨬ ஢ ਢ஢.
஢ઠ ਢ஢  ᥣ⮢   -ଭ  ᥣ⮢ 㤮⮢,  DPL  訩 ஢ ਢ஢, 祬 CPL  RPL ᥫ. ଭ ᥣ  ஢ ਢ஢  ஢.
VERW (䨪 㯭 ) 筠  VERR :  믮 䨪 㯭 ᥣ    ⠭ 䫠 ZF, ᫨  ᥣ 㯥  ⥭.  VERW 㤮⮢,  ਯ   㦭 ࠭, ⢨⥫쭮  ਯ஬ ᥣ, ᥣ 㯥  ⥭   DPL   ਢ஢ ஢,  CPL  RPL ᥫ.  ᥣ   뢠 㯭묨  :  ଭ, ⠪  -ଭ. 

6.7.2  ⭮ 㪠⥫  RPL

襭 ஢ ਢ஢ (RPL)  । 砩 ᯮ짮 㪠⥫, ࠧ  ਢ஢     訬 ஢ ਢ஢.
࠭ ਬ஬  㦨 䠩 ⥬ 楤 FREAD (䨪_䠩, n_⮢, 㪠⥫_).  ᪠ 楤 뢠   ᪮ 䠩  ,   ࠭ ᠭ ᮤন ⮣ .  㦨  ணࠬ, ࠡ  ਪ ஢,  ᠬ  ࠡ  ਢ஢ ஢, ⮡ ᥣ   㦨 /뢮 樮 ⥬. ᫨ ਪ ணࠬ । ⮩ 楤  㪠⥫ ,  㪠뢠   ⪨     ਢ஢ ᭮ ࠭⢥, 楤  믮 ⢨, 騥  ࠧ襭 ⥬.
  ஡  ᯮ짮 RPL. RPL   ᥫ ८। ਢ஢.  ८। ਢ஢ ।⠢ ᮡ ஢ ਢ஢  ᥣ, ᣥ஢襣  ᥫ ᥣ.  襯ਢ ਬ RPL  ।⠢ ᮡ CPL ਪ ணࠬ, 맢襩 楤 ⥬ ஢.  i486 ⮬᪨ ஢  㦥  ᥣ ॣ ᥫ, ।, ᪠   RPL 믮 襭 .
 ⮣, ⮡ ᯮ짮 २⢠, 묨 ⠪ ஢મ ஬ RPL, 뢠 楤  ⮫쪮 ஢, ⮡  ।  ᥫ ᥣ  RPL  ⥬   訬 ஢ ਢ஢,   CPL 室 筨 . ᫨ ᥫ ᯮ  㯠  ᥣ,  ஬ 筨     , .. RPL ண   ਢ஢, 祬 DPL 襭 ᥣ,   㧪 ᥫ  ᥣ ॣ  ᪫祭 饩 .
ARPL (ந 襭 ஢ ਢ஢) ࠨ  RPL ᥫ ᥣ  襥  祭 (訩 ஢ ਢ஢), 롨   室 祭  祭  RPL  ᥫ ᥣ, ᠭ  ॣ 饣 祭.  RPL 室     ᥫ ᥣ  ॣ. ᫥ 筮 ।⠢ ᮡ  ॣ CS 뢠饩 楤  ⥪. ᫨  ⠪ ன RPL ᥫ ,  ந室 ⠭ 䫠 ZF;  ⨢ 砥 䫠 ZF 頥. 

6.8    ஢ ࠭

 ࠡ⠥   ஢ ᥣ⮢, ⠪   ஢ ࠭.  ᯮ짮 ᪮  ᥣ樨    ஢ ࠭ ⠪ ।頥 ⨬  ﭨ  ணࠬ.
 뫪   ஫  㤮⢮७ ஢ப .  ஢ન 믮  砫 横 饭  ;  襭  ।頥 砫 ⮣ 横   ᪫祭. ᪮  ஢ન 믮 ࠫ쭮  ࠭樥 ,    ⥫  ६ .    ஢ન   ஢ ࠭: 
1. ࠭祭  㥬  .
2. ஢ઠ ⨯. 

襭  ਢ  樨 ᪫祭. 堭 ᪫祭 ᠭ   9.    ᠭ 襭 , 騥  ᪫祭. 

6.8.1   ࠭ ⠡ ᮤঠ ࠬ 

 㭪 6-10    ࠭筮 ⠡,  ࠢ 㯮  ࠭. ஢ન  ਬ  ࠭ ⠡栬  ࢮ, ⠪  ண ஢. 

6.8.1.1  ࠭祭 㥬  

 ࠭  ᥣ⮢ ⨥ ਢ஢  -ࠧ.  ᥣ⮢   ஢ ਢ஢,     0 (訩 ஢ ਢ஢)  3 (訩 ஢ ਢ஢).  ࠭   ஢ ਢ஢: 
1. ஢ 㯥ࢨ (U/S=0) -  樮 ⥬, 祣 ⥬ ணࠬ ᯥ祭 (ਬ, ࠩ஢ ன),  ⠪  頥 ⥬  (ਬ, ࠭ ⠡).
2. ஢ 짮⥫ (U/S=1) -  ਪ   . 

஢ ਢ஢, ᯮ㥬  ᥣ樨, ⮡ࠦ  ஢ ਢ஢ ࠭. ᫨ CPL ࠢ 0, 1  2,   ࠡ⠥  ஢ 㯥ࢨ. ᫨  CPL ࠢ 3,   ࠡ⠥  ஢ 짮⥫.   ࠡ⠥  ஢ 㯥ࢨ,  ࠭  㯭묨.   ࠡ⠥  ஢ 짮⥫, 㯭 ⮫쪮 ࠭, 騥 ஢ 짮⥫. 

31                               12 11                      0
--------------------------------------------------------------
|                                  |       |   | | |P|P|U|R| |
|  ࠭筮  31...12  |㯭|0 0|D|A|C|W|/|/|P|
|                                  |       |   | | |D|T|S|W| |
--------------------------------------------------------------

R/W   ⥭/
U/S   짮⥫/㯥ࢨ

     㭮 6-10.    ࠭筮 ⠡

6.8.1.2  ஢ઠ ⨯

堭  ᯮ ⮫쪮   ࠭:
1.  쪮  ⥭ (R/W=0)
2.   ⥭/ (R/W=1). 

  ࠡ⠥  ஢ 㯥ࢨ  饭  WP  ॣ CR0 ( ﭨ , ᮮ⢥饬 樠樨   ⥬),  ࠭  ६ 㯭묨  ⥭   (ਧ   ).   ࠡ⠥  ஢ 짮⥫,    㯭  ࠭ ஢ 짮⥫, 祭 ਧ ⥭/. ࠭ ஢ 짮⥫, 祭  ⥭/  쪮  ⥭,  㯭묨  ⥭. ࠭ ஢ 㯥ࢨ  ஢ 짮⥫ 㯭   ⥭,   .  ⪥ 襭 ࠢ 㯠  饭 ࠭栬  ᪫祭 饩 .
 ⫨稥   386 DX  i486   ࠭ ஢ 짮⥫    ० 㯠 㯥ࢨ. ⠭  WP  ॣ CR0 砥 ⢨⥫쭮 ० 㯥ࢨ   ࠭    ० 짮⥫.  ।⢮   ॠ樨 ⥣ "--", ᯮ㥬 묨 樮묨 ⥬, ਬ UNIX,  ᮧ  ( ।⢮ ⠪ 뢠 ஦ ࠫ ᮢ   ஦).
 ᮧ    ᪮஢  ᭮ ࠭⢮ ஦饩 .   ஦  , 㡫  ᥣ⮢  ࠭ ஦饩 . ⥣ "--"     ६, ⮡ࠦ ஦ ᥣ  ࠭    ᥣ  ࠭,  ᯮ ஦饩 祩. ⭠  ࠭ ᮧ ⮫쪮  砥,     믮    ࠭. 

6.8.2  ꥤ  ࠭ ⠡  ஢

  ⤥쭮 ࠭ ਡ  ᮮ⢥饣   ⠫ ࠭ (⠡ ࠭ ࢮ ஢)  ⫨  ਡ⮢   ⠡ ࠭ ண ஢.  i486 ஢  ࠭, ᬠਢ ਡ ,   ⠡  ஢.   6-4  , ᯥ稢 묨 ﬨ ਡ⮢   饭  WP. 

        6-4. ꥤ  ⠫ ࠭
                        ⠡ ࠭
----------------------------------------------------------------
|   ⠫      ⠡       ꥤ     |
|      ࠭              ࠭               䥪       |
|--------------------------------------------------------------|
|ਢ|         |ਢ|         |ਢ|         |
|஢|㯠     |஢|㯠     |஢|㯠     |
|  |            |  |            |  |            |
|--------------------------------------------------------------|
|짮|쪮⥭|짮|쪮⥭|짮|쪮⥭|
|짮|쪮⥭|짮|⥭|짮|쪮⥭|
|짮|⥭|짮|쪮⥭|짮|쪮⥭|
|짮|⥭|짮|⥭|짮|⥭|
|짮|쪮⥭|㯥 |쪮⥭|짮|쪮⥭|
|짮|쪮⥭|㯥 |⥭|짮|쪮⥭|
|짮|⥭|㯥 |쪮⥭|짮|쪮⥭|
|짮|⥭|㯥 |⥭|짮|⥭|
|㯥 |쪮⥭|짮|쪮⥭|짮|쪮⥭|
|㯥 |쪮⥭|짮|⥭|짮|쪮⥭|
|㯥 |⥭|짮|쪮⥭|짮|쪮⥭|
|㯥 |⥭|짮|⥭|짮|⥭|
|㯥 |쪮⥭|㯥 |쪮⥭|㯥 |⥭|
|㯥 |쪮⥭|㯥 |⥭|㯥 |⥭|
|㯥 |⥭|㯥 |쪮⥭|㯥 |⥭|
|㯥 |⥭|㯥 |⥭|㯥 |⥭|
----------------------------------------------------------------


6.8.3  ८।  ࠭

  㯠 ஢,  騥 ஢ ਢ஢ 0,   祭 CPL: 
-   ਯࠬ ᥣ⮢ (LDT, GDT, TSS  IDT).
-   ७ ⥪  ६ 믮  CALL,  ᪫祭  뢠,  ந室  ஢ ਢ஢.

6.9 ꥤ  ᥣ⮢  ࠭

 ࠧ襭 堭 窨 ࠭  i486 ᭠砫 믮 ஢ન  ᥣ,  ⥬ ஢ન  ࠭. ᫨  㦨 襭     ஢ ,  ᥣ, ⠪  ࠭, 믮  த:  ᪫祭. ᫨ ᪫祭  堭  ᥣ⮢, ᪫祭  ࠭  .
ਬ,  । 让 ᥣ , 騩    ਡ⮬ 㯠 쪮  ⥭,  㣨  -  ⥭/.  ⮬ 砥  ⠫ ࠭ ( ⠡ ࠭)  ⥩  㯮 쪮  ⥭    U/S  R/W, 騥 ⢨ ࠢ 㯠  ᥬ ࠭栬, ᠭ  ⮬ ⠫ ( ⤥ ࠭栬,   ࠭ ⠡ ண ஢).  ⮤   ᯮ짮, ਬ,  । 讣 ᥣ ,  ண ।祭 쪮  ⥭ ( ࠧ塞  -१ ).  ᠬ । "᪮" ࠭⢮    让 ᥣ,  "᪨" 㪠⥫ﬨ, ᯮ㥬묨  㯠  ⮬ "᪮" ࠭⢮,  ⮩ ࠧ塞 , ࠧ塞 䠩, ⮡ࠦ  㠫쭮 ࠭⢥,  ⠪ ⥩ 㯥ࢨ.
