
 7  ⨧筮

 i486 ᯥ稢  প ⨧筮. 祩 뢠 ணࠬ, 믮塞  ⥪騩 ,   믮  ६ ࠡ 㣮 ணࠬ.  ᪠ 뢠, ᪫祭, 室  맮.      । ࠢ ᯮ  祭,  ⮬   ਯ ⠡,  ਯ   ⨯, 뢠騩 砫 믮   ᫥ ࠭ ﭨ ⥪饩 .   ⨯ -ਥ஢ ਯ஢,   室  ⠡ ਯ஢: ਯ ᥣ ﭨ    .  ࠢ ।   ⠪ ਯ஢, ந室 ४祭 .
४祭  宦  맮 楤,   믮 ࠭ 襣 ⢠ ଠ樨  ﭨ . 맮 楤 ࠭ ⮫쪮 ᮤন ॣ஢ 饣 祭,     ᮤন ⮫쪮  ॣ (EIP).  맮 楤 ᮤন ࠭塞 ॣ஢ 頥  ⥪, ⮡ 楤   맢 ᠬ ᥡ.  楤 뢠 ᠬ ᥡ,  뢠 ॥ࠡ쭮.
४祭  । 믮    ।, । .  ⮣ ॡ ࠭ ᮤন ࠪ᪨  ॣ஢ , ⠪  ॣ EFLAGS.  ⫨稥  楤,   ॥ࠡ. ४祭  祣  頥  ⥪. ଠ  ﭨ  ࠭     ,  뢠 ᥣ ﭨ .
 ᫮ ॣ஢   , ন ⨧筮, 室:
-  ﭨ .
- ਯ ᥣ ﭨ .
-  
- ਯ  .

ᯮ  ,  i486  ४ 믮     , ࠭ ⥪ ⥪饩 , ᪠ ⥬ ᠬ  㣮 .  ⮣ ४祭 ,  i486 ।   ।⢠ ࣠樨 ⨧筮:
1. ४祭   믮 ᫥⢨ 뢠  ᪫祭 (᫨  ॡ 樨 ⥬).   ⮫쪮 믮 ४祭   ࠡ⪨ 뢠  ᪫祭,   ⮬᪮ ४祭 ,  ࢠ , ᫥   뢠  ᪫祭. 뢠  ந室   ६  ࠡ⪨ 뢠.
2.   ४祭     i486  ⠪ 믮 ४祭   LDT.   ᯮ짮  ⮣, ⮡    ᮡ⢥ ⮡ࠦ ᪨ ᮢ  䨧᪨.  ᠬ ᯥ稢 ⥫쭮 ।⢮ , ᪮    ⠪ ࠧ ஢,    ﭨ   㣠 ᪫祭.  PDBR ⠪ १㦠.   ᯮ짮 堭 窨 ࠭  ᯥ祭 ஢ .

ᯮ짮 堭 ⨧筮  易⥫.   ਪ ணࠬ  ᯮᮡ ࣠樨 믮 ணࠬ   訬.  室 襩 ᪮ ॠ樨  뢠, ६, ஥ ॡ  ࠭ ﭨ   ४祭    ᫨誮 訬.  ⮩ 樨  ஬    ⮬, ⮡ ᯮ짮 -ਥ஢  ,  믮 ४祭  ணࠬ묨,   묨 ।⢠.   ࠭ 襥 ⢮ ଠ樨  ﭨ .  ⮤     ⮤ ⨬樨, ᯮ㥬  襭 ࠪ⨪ த⢨ ⥬ ᫥ ॠ樨  㭪樨 ⥬.

7.1  ﭨ 

ଠ  ﭨ , 室  ⠭ ⥪ , ࠭  ⨯ ᥣ, 뢠 ᥣ⮬ ﭨ ,  TSS.  㭪 7-1  ଠ TSS  , 믮塞 業ࠫ ஬ i486 (ᮢ⨬  砬 80286 ᯥ稢 㣨 ⨯ TSS: .  21).  TSS    ᭮ ⥣ਨ:
1. ᪨ , 塞 ஬   ४祭 .  ᫮   室:
-  饣 祭 (EAX, ECX, EDX, EBX, ESP,EBP, ESI  EDI).
-  ॣ (ES, CS, SS, DS, FS  GS).
-  䫠 (EFLAGS).
- ⥫  (EIP),
-   TSS ।饩  ( ⮫쪮   ).
2. ᪨ ,   뢠,   .   ⠭  ᮧ .  :
-   LDT .
- ᪨   ⥪ ਢ஢ ஢ 0, 1  2.
-  T ( ⫠筮 誨), ,  ⠭, ⠢  ⠭  ४祭  ⫠筮 ᪫祭. ( ஡ ଠ  ⫠ .   11).
-   ⮢ ᨢ ࠧ襭 /뢮.  稨,  ᨢ ᥣ ࠭  TSS  訬 ᠬ.   㪠뢠  砫 ᨢ. ( ஡ ଠ  ⮢ ᨢ ࠧ襭 /뢮 .   8). 

 ᯮ짮 堭 窨 ࠭   饭 ࠭ ࠭  ।  TSS, 뢠 ஬  ४祭  ( 108 ⮢). ᫨ ࠭ ࠭ 室  । ⮩  TSS,  ࠭   ஭ ࠭  ⢮   ६.  ⢨ ࠭  樨 ᪫祭 饩  ᫥ ⮣,   砫 ⥭ TSS,  ﭨ ⠭ 訡. 

7.2 ਯ TSS

 ﭨ ,    稥 ᥣ, । ਯ஬. ଠ ਯ TSS   㭪 7-2. 

31                       15                     0
--------------------------------------------------
|  ᨢ   |    000000000000000  |T|  64
|  /뢮          |                     | |
|------------------------------------------------|
|  0000000000000000      |  LDT |
|------------------------------------------------|
|  0000000000000000      |         GS            |
|------------------------------------------------|
|  0000000000000000      |         FS            |
|------------------------------------------------|
|  0000000000000000      |         DS            |
|------------------------------------------------|
|  0000000000000000      |         SS            |
|------------------------------------------------|
|  0000000000000000      |         CS            |
|------------------------------------------------|
|  0000000000000000      |         ES            |
|------------------------------------------------|
|                       EDI                      |
|------------------------------------------------|
|                       ESI                      |
|------------------------------------------------|
|                       EBP                      |
|------------------------------------------------|
|                       ESP                      |
|------------------------------------------------|
|                       EBX                      |
|------------------------------------------------|
|                       EDX                      |
|------------------------------------------------|
|                       ECX                      |
|------------------------------------------------|
|                       EAX                      |
|------------------------------------------------|
|                     EFLAGS                     |
|------------------------------------------------|
|                       EIP                      |
|------------------------------------------------|
|                    ࢨ               |
|------------------------------------------------|
|  0000000000000000      |         SS2           |
|------------------------------------------------|
|                      ESP2                      |
|------------------------------------------------|
|  0000000000000000      |         SS1           |
|------------------------------------------------|
|                      ESP1                      |
|------------------------------------------------|
|  0000000000000000      |         SS0           |
|------------------------------------------------|
|                      ESP0                      |
|------------------------------------------------|
|  0000000000000000      |        |
|                        |( ᥫ TSS)  |
--------------------------------------------------

   ⭠筮 ଠ 

: , 祭  0, १ࢨ.  ᯮ . 
㭮 7-1.  ﭨ 

 ""    㪠뢠  ,   . ⮩ 祩 뢠 ⥪ 믮塞   믮 .    祭 9 㪠뢠  -⨢ ; 祭 11 (筮) 㪠뢠   .  -॥ࠡ.  i486 ᯮ    㦥 ⮪ 맮 , 믮 ன ࢠ. 

                       ਯ TSS

               2 2 2 2 2 1 1 11  1 11  1 1 1
31             4 3 2 1 0 9 8 76  5 43  2 1 0 9 8 7            0
----------------------------------------------------------------
|               | | | |A|      |  | D | |       |              |
| BASE  31:24   |G|D|0|V|LIMIT |P | P | | TYPE  |  BASE 23:16  |+4
|               | | | |L|19:16 |  | L |0|1|1|B|1|              |
|--------------------------------------------------------------|
|        15:00     |     ࠭ ᥣ 15:00    |+0
----------------------------------------------------------------

AVL       㯭  ᯮ짮 ⥬ ணࠬ
          ᯥ祭
B          ""
BASE        ᥣ
DPL       ஢ ਢ஢ ਯ
G         ࠭
࠭   ࠭ ᥣ
P         ⢨ ᥣ
TYPE       ᥣ

 㭮 7-2. ਯ TSS 

   ᥣ, ࠭  DPL,  ⠪  ࠭樨  ⢨ 믮 㭪樨,  ⥬,  뫨    ਯ ᥣ⮢ .  ࠭   祭, ࠢ   祬 67H,     쭮 ࠧ ᥣ ﭨ . ⪠ 믮 ४祭  , ਯ TSS ன  ࠭  祬 67H,  ᪫祭.  ᯮ짮 ⮢ ᨢ ࠧ襭 /뢮 ॡ 襥 祭 ࠭. 襥 祭 ࠭  ⠪   ᠬ 樮 ⥬, ᫨ ⥬ ࠭  TSS ⥫ .
楤  㯮  ਯ TSS  맢 ४祭 .  設⢥ ⥬  DPL ਯ஢ TSS   饭, ⮡ ⮫쪮 ਢ஢ ணࠬ ᯥ祭  믮 ४祭 .

  ਯ TSS   楤    ஢ ਯ. ⥭  䨪   ⮫쪮 ⥬ ⮡ࠦ      ਯ . 㧪 ਯ TSS  ᥣ ॣ 뢠 ᪫祭. ਯ TSS  室 ⮫쪮  ⠡ GDT. ⪠ 㯠  TSS   ᥫ  ⠭ ⮬ TI ( 砥 ⥪ LDT)  ᪫祭. 

7.3   

  (TR) ᯮ  ᪠ ⥪饣 TSS.  㭪 7-3  ,  ஬  믮   TSS. 

 ﭨ     -----
--------------------- <-----| + |<------------------
|                   |       -----                   |
|                   |         ^                     |
|                   |         |                     |
|                   |         |                     |
|                   |         |                     |
|                   |         |                     |
|                   |         |                     |
|                   |         |                     |
|                   |         |                     |
---------------------         |                     |
                              |                     |
                  |       |
---------------------------------------------------------------
|           |        | ࠭ ᥣ   |TR
---------------------------------------------------------------
       |                     ^                     ^
       |                     |                     |
       |                      ----------------     |
       |                                      |    |
       |                                      |    |
       |              쭠              |    |
       |        ⠡ ਯ஢          |    |
       |       ------------------------       |    |
       |       |           |          | N     |    |
       |       |----------------------|       |    |
       |       |                      |       |    |
       |       |----------------------|       |    |
       |       |           |          |       |    |
       |       |----------------------|       |    |
       |       |                      |       |    |
       |       |----------------------|       |    |
       |       |           |          |       |    |
       |       |----------------------|       |    |
       |       |                      |       |    |
       |       |----------------------|       |    |
       |       |                      |-------     |
        ------>|     ਯ TSS   |            |
               |                      |------------
               |----------------------|
               |           |          |
               |----------------------|
               |                      |
               |----------------------|
               |           |          |
               |----------------------|
               |                      |
               |----------------------|
               |           |          |
               |----------------------|
               |                      |
               |----------------------|
               |           |          |
               |----------------------|
               |                      | 0
               ------------------------

                    㭮 7-3.  TR

   ""  (.. ,   뢠   ணࠬ ᯥ祭)  ""  (.. , 㦨 ஬  㯭 ணࠬ ᯥ祭). , 室騩   ,  ਯ TSS  GDT.  ᯮ   ॣ TR  ਥ 㤠 祭   ࠭  ਯ TSS. ࠭  ॣ  祭  믮   䥪⨢, ᪮  뫪  TSS ⥪饩    ॡ   祭  .
 LTR  STR ᯮ  䨪樨  ⥭   ॣ .    ਭ  ࠭,   16-ࠧ來 ᥫ ᥣ, ᯮ     ॣ 饣 祭.

LTR (㧨 ॣ ) 㦠    ॣ  ࠭,   ஢  ਯ TSS  GDT.  LDT ⠪ 㦠    ଠ  ਯ TSS.  LTR  ਢ஢ :    믮 ⮫쪮  CPL ࠢ 0.  LTR 筮 ᯮ  ६ 樠樨 ⥬  饭  ॣ  室 祭:  ᮤন ॣ TR  ᮡﬨ, 뢠騬 ४祭 .
STR (࠭ ॣ ) 뢠   ॣ   ॣ 饣 祭   .  STR   ਢ஢ . 

7.4  ਯ  

ਯ   ᯥ稢 ᢥ, 饭 뫪  . ଠ     㭪 7-4.
     ਯ TSS. RPL   ᥫ  ᯮ.
DPL   ࠢ 㯮  ਯ  ४祭 . 楤    ਯ     ,  RPL ᥫ  CPL 楤   ᫥   ࠢ DPL ਯ.  ᠬ ।頥 ४祭   ਢ஢묨, 祬  ᠬ, 楤ࠬ. (⬥⨬,   ᯮ짮   DPL ਯ TSS 祭  ᯮ).

                    ਯ  

                               1 1 1 1 1 1 1
31                             6 5 4 3 2 1 0 9 8 7            0
---------------------------------------------------------------
|                              | | D |         |              |
|        ࢨ         |P| P |0 0 1 0 1| ࢨ|+4
|                              | | L |         |              |
|-------------------------------------------------------------|
|       ᥣ TSS   |       ࢨ          |+0
---------------------------------------------------------------

DPL ஢ ਢ஢ ਯ P ⢨ ᥣ
㭮 7-4. ਯ  

楤  㯮     맢 ४祭 ,   楤  㯮  ਯ TSS.   , ⠪  ਯ TSS ।祭  襭 ᫥ ᮢ: 1. 室    ⮫쪮   . ᪮   ࠭  ਯ TSS,     ⮫쪮  ⠪ ਯ. ,  ⢮ ᪮쪮  , 롨  ਯ TSS. 2. 室 ᯥ ᥫ⨢   砬.      ஡, ᪮   ࠧ  LDT   DPL, ⫨  DPL ਯ TSS. 楤, 筮 ਢ஢  ᯮ짮 ਯ TSS  GDT ( 筮  DPL, ࠢ 0),  ⥬   맢  , ᫨        LDT.    樮 ⥬  ࠭ ४祭  묨 砬. 3. 室 믮 ४祭   砥 뢠  ᮡ

7.5  ४祭 

 i486 । ࠢ 㣮     ᫥  砥: 
1.   믮  JMP  CALL  ਯ TSS. 
2.   믮  JMP  CALL   . 
3. 뢠  ᪫祭     IDT. 
4.   믮  IRET  ⠭ 䫠 NT.

 JMP, CALL  RET, ࠢ  뢠  ᪫祭, ।⠢ ᮡ  堭  i486,    ᯮ짮   ⥫⢠,  ਢ  ४祭 .  ਯ ( 맮 )  䫠 NT (   ) । ࠧ  ⠭ 堭   ମ, 뢠饩 ४祭 .  ⮣, ⮡ ந諮 ४祭 ,  JMP  CALL  । ࠢ  ਯ TSS,   . 䥪    :  i486 । ࠢ ॡ㥬 . ᪫祭  뢠 뢠 ४祭 ,     IDT. ᫨    IDT  뢠   誨,  ४祭   ந室.  ஡ ଠ  堭 뢠 .   9. 
                                               
                                               ﭨ 
                                               -----------------
쭠                쭠            |               |
⠡ ਯ஢     ⠡ ਯ஢  |               |
-----------------        -----------------     |               |
|       |       |        |       |       |     |               |
|---------------|        |---------------|     |               |
|               |        |               |     |               |
|---------------|        |---------------|     |               |
|       |       |        |       |       |     |               |
|---------------|        |---------------|     |               |
|               |        |               |     |               |
|---------------|        |---------------|     |               |
|       |       |------->|       |       |     |               |
|-   -|      ->|ਯ TSS |---->-----------------
|---------------|     |  |---------------|
|       |       |     |  |       |       |
|---------------|     |  |---------------|
|               |     |  |               |
|---------------|     |  |---------------|
|       |       |     |  |       |       |
|---------------|     |  |---------------|
|               |     |  |               |
|---------------|     |  |---------------|
|       |       |     |  |       |       |
|---------------|     |  |---------------|
|               |     |  |               |
-----------------     |  -----------------
                      |
                      |
                      |
                      |
 ਯ஢  |
뢠            |
-----------------     |
|       |       |     |
|---------------|     |
|               |     |
|---------------|     |
|       |       |     |
|---------------|     |
|               |     |
|---------------|     |
|       |       |     |
|-  --|-----
|---------------|
|       |       |
|---------------|
|               |
|---------------|
|       |       |
|---------------|
|               |
|---------------|
|       |       |
|---------------|
|               |
-----------------

 㭮 7-5.   뫪    

ணࠬ 㦨 뢠 ᥣ 頥 믮  ࢠ 楤,   室  㣮 . ᫨ 䫠 NT 饭, ந室 ଠ . ᫨ 䫠 NT ⠭, ந室 ४祭 . , ਭ ४祭,  ᥫ஬ TSS  TSS ணࠬ 㦨 뢠. 

४祭   ᫥騥 ⠯:
1. ஢ઠ ⮣,  ⥪饩  ࠧ襭 믮 ४祭   .   JMP  CALL ਬ ࠢ ਢ஢ 㯠  . DPL ਯ TSS       祬  ࠢ ६ CPL  RPL ᥫ . ᪫祭, 뢠   IRET  ࠢ ४  ᨬ  DPL    ਯ TSS 祭.
2. ஢ઠ ⮣,  ਯ TSS   祭  騩   ⨬ ࠭ (ॢ  ࠢ 67H).  稢訥  ⮩ 窨 訡 ਭ ⥪ ⥪饩 .  ⪥ 믮 ਢ  訡   訡 ⠭   ﭨ .  ⮬    ࠡ稪 뢠 㪠뢠  , 맢 訡,    , ᫥  . ࠡ稪 ᪫祭  䨪஢ ᫮, 맢襥 訡,  믮  . ⥫⢮ ࠡ稪 ᪫祭    ஧筮  ਪ ணࠬ.
3. ࠭ ﭨ ⥪饩 .  室   ⥪饣 TSS  ॣ .     ⥪騩 TSS (ॣ EAX, ECX, EDX, EBX, ESP, EBP, ESI, EDI, ES, CS, SS, DS, FS, GS  EFLAGS).
4. 㧪  ॣ TR ᥫ  ਯ TSS  , ⠭      ⠭  TS  ॣ CR0.    ࠭  JMP  CALL,     .
5. 㧪 ﭨ     TSS  த  믮.  ⮬ 㦠 ॣ LDTR, EFLAGS, ॣ 饣 祭 EIP, EAX, ECX, EDX, EBX, ESP, EBP, ESI, EDI,  ⠪ ᥣ ॣ Es, CS, SS, DS, FS  GS.  訡, 㦨  ⮬ 蠣, ਭ  ⥪  .  窨 ७ ࠡ稪 ᪫祭 ࢠ      믮. 

⬥⨬,  ﭨ ன   ४祭  ᥣ ࠭.   ⮩  믮  த  ⮩ ,  뫠  믮 ᫥饩  筮 ࠡ.  ⠭   祭,      ⠭   ४祭. 
 ४祭  ⠭  TS ( ४祭) ॣ CR0.  TS  ⥬ ணࠬ  न樨 ࠡ 楫᫥    権  饩 窮  ᮯ.  TS 㪠뢠  ,  ᮤন  権  饩 窮  ᮯ  ⫨  ᮮ⢥饣 ᮤন  ⥪饩 .   10  TS  ᮯ ᬠਢ  ஡.
ணࠬ 㦨 ᪫祭, 맢 ४祭  (᪫祭 ᫥⢨ 蠣 5 - 17  ⠡ 7-1)   뢠 ४ᨢ  砥 ⪨ १㧨 ᥫ ᥣ, ᣥ஢襣  ᪫祭. 稭 ᪫祭 (   ᪮쪨 稭)  ७ 㧪 ᥣ   䨪஢.
஢ ਢ஢,   믮﫠  ,   ⭮襭  ஢ ਢ஢  . ᪮  ஢   㣠  ⤥  ࠭⢠  ᥣ⠬ ﭨ ,  ᪮   TSS 믮  ࠢ ਢ஢, ४祭   ॡ  ஢ப ਢ஢.   稭 믮  ஢ ਢ஢, 㪠  RPL  ᮤন ॣ CS, 㦠  TSS.
஢ન, 믮塞  ४祭  

 7-1 
-----------------------------------------------------------------
  ஢塞 ᫮               ᮡ  1)   뫪
                                              訡
-----------------------------------------------------------------
 1   ਯ TSS          NP      TSS  
      

 2   ਯ TSS               GP      TSS  

 3   ࠭ ᥣ TSS  祬     TS      TSS  
      ࠢ 103
-----------------------------------------------------------------
 4   㧪 ॣ஢  祭, ࠭  TSS
-----------------------------------------------------------------
 5   ⨬ ᥫ LDT          TS      TSS  
      

 6   DPL  ᥣ               TS     ᥣ 
     ᮮ⢥ RPL ᥫ
                               2)
 7   ⨬ ᥫ SS           GP    ᥣ ⥪

 8    ⥪    SF    ᥣ ⥪

 9   DPL ᥣ ⥪                  SF    ᥣ ⥪
     ᮮ⢥ CPL

10   LDT          TS      TSS  
      
                               2)
11   ⨬ ᥫ CS           TS     ᥣ 

12                NP     ᥣ 
      

13   DPL ᥣ ⥪                  GP    ᥣ ⥪
     ᮮ⢥ RPL ᥫ

14   ⨬ ᥫ஢             GP   ᥣ 
     DS,ES,FS  GS             2)

15    DS,ES,FS  GS 㯭     GP   ᥣ 
      ⥭

16    DS,ES,FS  GS              NP   ᥣ 
       

17   DPL ᥣ⮢ DS,ES,FS  GS         GP   ᥣ 
       ࠢ CPL (᫨ 
     ᥣ   ଭ묨)
-----------------------------------------------------------------

ਬ砭: 騥  Intel  ᯮ짮 㣮 冷 ஢ப.

1. NP = ᪫祭 "  "; GP= ᪫祭 饩 ; TS= ᪫祭 " TSS"; SF=᪫祭 "  ⥪".
2.   ⨬, ᫨  室  ⠡ ᮢ⨬ ⨯ (ਬ, ᥫ LDT   室    ⠡, ஬ GDT),    । ࠭ ⠡筮 ᥣ  뫠  ᮢ⨬ ⨯ ਯ (ਬ, ᥫ  ॣ CS  ⨬ ⮫쪮  ⮬ 砥, ᫨   ਯ  ᥣ; ⨯ ਯ     ). 

7.6   

  믮  ।  ᯮ    TSS  䫠 NT.  NT 㪠뢠  ,   ⥪ 믮塞    믮 㣮 ,     TSS ⥪饩  ᮤন ᥫ TSS    襣 ஢, ᫨ ⠪  (. 㭮 7-6).
 뢠, ᪫祭, 室  맮 뢠 ४祭 ,  i486  ᥫ ᥣ ﭨ ⥪饩   TSS     ⠭ 䫠 NT.  NT 㪠뢠  ,    TSS 뫮 㦥 ᥫ஬ ࠭ TSS.   頥 ࠢ  IRET.  믮  IRET ந室 ஢ઠ 䫠 NT. ᫨  ⠭,   믮 ४祭  । .   7-2  ᯮ짮  TSS,    ४祭 .

⬥⨬,  䫠 NT   ஢ ணࠬ ᯥ祭, 믮塞   ஢ ਢ஢. ணࠬ  ⠭ ᢮  NT  믮  IRET,  㤥  䥪 ᪠ ,     TSS ⥪饩 .  ।饭 ।ᬮ७ ४祭  樮 ⥬  樠஢    ᮧ  TSS.

                ᠬ   
  襣              㡮       믮塞
  ஢                      ஢          
                              

   TSS             TSS            TSS           EFLAGS
------------   ------------   ------------   ------------
|          |   |          |   |          |   |   NT=1   |
|          |   |          |   |          |   ------------
|          |   |          |   |          |
|  NT=0    |   |  NT=0    |   |  NT=0    |
|          |   |          |   |          |
|          |   |          |   |          |
|          |   |          |   |          |
|     -----|   |     -----|   |     -----|   ------------
|     |LINK|   |     |LINK|   |     |LINK|   | TR|
------------   ------------   ------------   ------------
            \           |  \          |   \        |
             \__________|   \_________|    \_______|

LINK =   

                 㭮 7-6.   

           7-2. ⢨ ४祭 
                 , NT  
-----------------------------------------------------------------
           ⢨ JUMP   ⢨        ⢨
                                   CALL        IRET
                                   뢠
-----------------------------------------------------------------
    ⠭.     ⠭.     
    । ⨬   । ⨬    
                饭         饭        ⠭

    饭          .      饭
ன                       ⥪騩 
                                   ⠭

 NT         饭         ⠭     
 

 NT                       饭
ன 

                  㦥           
                        ᥫ஬  TSS
                       ன 

                          

ன 
-----------------------------------------------------------------

7.6.1    ।蠥 横

  ਯ TSS ।頥 ॥ࠡ ४祭 .    ࠭ ⥪  ,   ⥪, ࠭  TSS, ᫥⥫쭮,   ᢮ 襭   맢 ⮫쪮  ࠧ. 窠 ⫮       ᫥⢨ ⢥ 뢠, ᪫祭, 室  맮.   ।頥 맮 , ⠢  ⠪ 楯. ࠡ쭮  ४祭    TSS ,  ਢ  ࠧ襭 ᥩ 楯窨.

 ࣠   ᫥騬 ࠧ: 
1.  ४祭   ⠭    .
2.  ⭮ ४祭    頥   ன , ᫨      ⠢  楯 (.. , 맢 ४祭 ,   JMP  IRET). ᫨  ⠢  楯,     ⠥ ⠭.
3.  ४祭     ᪫祭 饩 , ᫨     뢠 㦥 ⠭. 

 ࠧ,  ।頥 ४祭  ᠬ  ᥡ,      楯窥 ,  ᪫砥 ॥ࠡ쭮 ४祭 .
   ᯮ짮  ୮ 䨣樨 ⥬, ᪮  ⠭  ⪥    墠뢠 設.  ᪫砥 ६    ⮩    ࠬ. ( ஡ ଠ  ୮ ࠡ⪥ .   13). 

7.6.2  䨪  

  믮 ࢠ   믮 ࢠ襩     䨪 楯窨 ⫮ .  ᯮᮡ ⮨  ᫥饬: 1.  뢠. 2. 砫    TSS  뢠,  ⥬     ਯ TSS , 㤠塞  楯窨. 3.  ࠧ 뢠. 

7.7  ᭮ ࠭⢮ 

 ⮣, ⮡    ᮡ⢥ LDT  ᮡ⢥ ⠡ ࠭,   ᯮ짮 ᥫ LDT   PDBR ( CR3) TSS. ᪮ ਯ ᥣ⮢  LDT ।⠢ ᮡ 離  砬  ᥣ⠬,  ⠭ 㠫쭮 ࠢ ⨬ 離     ᯮ짮 ⤥ LDT.    ⭮ ᥣ   ।  ⭮  ⥬ 饭 ਯ ⮣ ᥣ  LDT .  ࠧ襭 堭 窨     ᢮ ᮡ⢥  ࠭ ⠡  ⮡ࠦ  ᮢ  䨧᪨.
  ⠪   LDT.  ⮩  䥪⨢  ⠬  ᯮᮡ ࣠樨 㭨樨  砬  ࠢ   㣨,  ᭨  ஢  ⥬  楫. 
᪮      GDT, ⠪  ᮧ ࠧ塞 ᥣ⮢,    㤥 ந室 १ ᥣ ਯ   ⠡. 

7.7.1 ⮡ࠦ  ᭮ ࠭⢠   䨧᪮ 

ᮡ ࣠樨 ⮡ࠦ  ᭮ ࠭⢠   䨧᪮     : 
1.  ⮡ࠦ  ᭮ ࠭⢠  䨧᪮, ࠧ塞 ᥬ 砬. ᫨ 堭 窨 ࠭ 饭,   ᯮᮡ ⢥.  窨 ࠭    ⮡ࠦ    䨧᪨ .  ࠧ襭 窥 ࠭  ଠ ⮡ࠦ ⨣ ⥬ ᯮ짮  ⠫ ࠭   .  ᭮ ࠭⢮  ॢ 䨧᪮ ࠭⢮, ᫨ ন 㠫쭠   窮  饭.
2. ᨬ ⮡ࠦ  ᭮ ࠭⢠  䨧᪮.  ଠ ⮡ࠦ   ᯮ짮 ᮡ⢥ ⠫ ࠭   . ᪮ PDBR ( ॣ ⠫ ࠭) 㦠  TSS   ४祭 ,     ᮡ⢥ ࠭ ⠫.

  ࠭⢠ ࠧ   ⮡ࠦ   ࠧ 䨧᪨ . ᫨  ࠧ ࠭ ⠫ 㪠뢠  ࠧ ࠭ ⠡,   ⠡ 㪠뢠  ࠧ ࠭ 䨧᪮ ,  ⠪   ࠧ  䨧᪨ ᮢ .

 ﭨ   室  ࠭⢥, 㯭 ᥬ 砬, ⠪ ࠧ ⮡ ⮡ࠦ ᮢ TSS  﫮  ६ ⥭   ஬ TSS  ४祭 .  ࠭⢮,  ஥ ⮡ࠦ GDT, ⠪   ࠧ塞 䨧᪨ ࠭⢮;  ⨢ 砥   GDT.  㭪 7-7 ,   ࠭⢠    ४뢠  䨧᪮ ᭮ ࠭⢥  ࠧ  ࠭ ⠡. 

7.7.2  ᪮ ᭮ ࠭⢮ 

  ᥡ ⮡ࠦ  ᭮ ࠭⢠  䨧᪮  ४⨥   ࠧ  砬.  ࠧ    ⠪  饥 ⮡ࠦ ᪮ ᭮ ࠭⢠  , ..  ⠪     ਯࠬ, 㪠뢠騬  ࠧ塞  ᭮ ࠭⢮.   ᯮᮡ ᮧ ࠧ塞 ⮡ࠦ ᪮ ᭮ ࠭⢠  䨧᪮: 
1.   ᥣ ਯ஢  GDT.      ਯࠬ  GDT. ᫨  ਯ 㪠뢠   ᭮ ࠭⢮, ⮡ࠦ  饥    䨧᪮ ᭮ ࠭⢮,    ࠧ   .
2.   ࠧ塞 LDT.      ᯮ짮     LDT, ᫨ ᥫ LDT   TSS  ᯮ짮  ࠭樨 ᮢ 롨     LDT.  ਯ  LDT, 騥  ࠭⢠, ⮡ࠦ  ४뢠騥 䨧᪮ ᭮ ࠭⢮, ᯥ稢 ࠧ塞 䨧 .  ⮤ ࠧ  ᥫ⨢, 祬 ⮤ ࣠樨 ࠧ ।⢮ GDT, ᪮   ࠭ ࠧ 묨 砬. 稥   ⥬   㣨 LDT,  騥    ࠧ塞  .
3.   ᥣ ਯ஢  LDT, ⮡ࠦ       ᭮ ࠭⢮. ᫨  ᭮ ࠭⢮ ⮡ࠦ    ᠬ 䨧᪮ ᭮ ࠭⢮   ࠭筮 ⮡ࠦ  ,  ਯ  砬 ࠧ ᭮ ࠭⢠.  ਯ 筮 뢠 "ᠬ".  ⮤ ࠧ   ᥫ⨢, 祬 ।騩: 稥 ਯ  LDT  㪠뢠  ᨬ  ,  騥 ࠧ塞묨.
                                                    ࠭
    TSS                                               
                                                   -------------
                                                   | ࠭  |
                   ⠫                 |     |
TSS  A       ࠭         ࠭       ->|          |
------------     ------------     ------------  |  -------------
|          |     |          |     |          |  |
|          |     |----------|     |----------|  |  -------------
|          |     |          |     |   |--   | ࠭  |
|          |     |----------|     |----------|     |     |
|          |     |          |     |   |---->|     A     |
|----------|     |----------|     |----------|     -------------
|   PDBR   |---->|   |---->|   |--
|----------|     |----------|     ------------ |   -------------
|          |     |   |--                |   | ࠭  |
------------     ------------  |               --->|     |
                               |                   |     A     |
                               |  塞      -------------
                               |  ⠡ ࠭
                               |  ------------
                               |  |          |
                               |  |----------|     -------------
                               |  |          |     |塞|
                               |  |----------|     |  ࠭ |
                               |  |   |---->|           |
                               |  |----------|     -------------
                                ->|   |--
                                ->------------ |   -------------
TSS  B                   |               |   |塞|
------------     ------------  |               |   |  ࠭ |
|          |     |          |  |               |   |           |
|          |     |----------|  |  ------------  -->-------------
|          |     |          |  |  |          |
|          |     |----------|  |  |----------|     -------------
|          |     |          |  |  |          |     | ࠭  |
|----------|     |----------|  |  |----------|     |     |
|  PDBR    |---->|   |--   |   |---->|          |
|----------|     |----------|     |----------|     -------------
|          |     |   |---->|   |--
------------     ------------     ------------ |   -------------
   TSS             ⠫             |   | ࠭  |
                   ࠭          ࠭    |   |     |
                                               |   |          |
                                                -->-------------
                                                     ࠭
                                                        

 㭮 7-7. ⮡ࠦ  ᭮ ࠭⢠  䨧᪮  ४⨥
