Figures Fig.7
Fig.7-1 80386 32-Bit Task State Segment
Figure 7-1. 80386 32-Bit Task State Segment
31 23 15 7 0
+---------------+---------------+---------------+---------------+
| I/O MAP BASE | 0 0 0 0 0 0 0 0 0 0 0 0 0 |T|64
|---------------+---------------+---------------+---------------|
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| LDT |60
|---------------+---------------+---------------+---------------|
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| GS |5C
|---------------+---------------+---------------+---------------|
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| FS |58
|---------------+---------------+---------------+---------------|
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| DS |54
|---------------+---------------+---------------+---------------|
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| SS |50
|---------------+---------------+---------------+---------------|
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| CS |4C
|---------------+---------------+---------------+---------------|
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| ES |48
|---------------+---------------+---------------+---------------|
| EDI |44
|---------------+---------------+---------------+---------------|
| ESI |40
|---------------+---------------+---------------+---------------|
| EBP |3C
|---------------+---------------+---------------+---------------|
| ESP |38
|---------------+---------------+---------------+---------------|
| EBX |34
|---------------+---------------+---------------+---------------|
| EDX |30
|---------------+---------------+---------------+---------------|
| ECX |2C
|---------------+---------------+---------------+---------------|
| EAX |28
|---------------+---------------+---------------+---------------|
| EFLAGS |24
|---------------+---------------+---------------+---------------|
| INSTRUCTION POINTER (EIP) |20
|---------------+---------------+---------------+---------------|
| CR3 (PDPR) |1C
|---------------+---------------+---------------+---------------|
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| SS2 |18
|---------------+---------------+---------------+---------------|
| ESP2 |14
|---------------+---------------+---------------+---------------|
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| SS1 |10
|---------------+---------------+---------------+---------------|
| ESP1 |0C
|---------------+---------------+---------------+---------------|
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| SS0 |8
|---------------+---------------+---------------+---------------|
| ESP0 |4
|---------------+---------------+---------------+---------------|
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0| BACK LINK TO PREVIOUS TSS |0
+---------------+---------------+---------------+---------------+
----------------------------------------------------------------------------
NOTE
0 MEANS INTEL RESERVED. DO NOT DEFINE.
----------------------------------------------------------------------------
Fig.7-2 TSS Descriptor for 32-Bit TSS
Figure 7-2. TSS Descriptor for 32-bit TSS
31 23 15 7 0
+-----------------+-----------------+-----------------+-----------------+
| | | | |A| LIMIT | | |S| Type | |
| BASE 31..24 |G|0|0|V| |P| DPL | | | BASE 23..16 | 4
| | | | |L| 19..16 | | |0|1|0|B|1| |
|-----------------------------------+-----------------------------------|
| | |
| BASE 15..0 | LIMIT 15..0 | 0
| | |
+-----------------+-----------------+-----------------+-----------------+
Fig.7-3 Task Register
Figure 7-3. Task Register
+-------------------------+
| |
| |
| TASK STATE |
| SEGMENT |<---------+
| | |
| | |
+-------------------------+ |
16-BIT VISIBLE ^ |
REGISTER | HIDDEN REGISTER |
+--------------------------------------------------------------+
TR | SELECTOR | (BASE) | (LIMT) |
+--------------------------------------------------------------+
| ^ ^
| +-----------------+ |
| GLOBAL DESCRIPTOR TABLE | |
| +-------------------------+ | |
| | TSS DESCRIPTOR | | |
| +-------------------------+ | |
| | | | | |---+ |
| |------------+------------| |
+------->| | |-------+
+-------------------------+
| |
+-------------------------+
Fig.7-4 Task Gate Descriptor
Figure 7-4. Task Gate Descriptor
31 23 15 7 0
+-----------------+----------------+-----------------+-----------------+
| | | | | |
| (NOT USED) |P| DPL |0 0 1 0 1| (NOT USED) | 4
| | | | | |
|----------------------------------+-----------------------------------|
| | |
| SELECTOR | (NOT USED) | 0
| | |
+-----------------+----------------+-----------------+-----------------+
Fig.7-5 Task Gate Indirectly Identifies Task
Figure 7-5. Task Gate Indirectly Identifies Task
LOCAL DESCRIPTOR TABLE INTERRUPT DESCRIPTOR TABLE
+-------------------------+ +-------------------------+
| | | |
| TASK GATE | | TASK GATE |
+-------------------------+ +-------------------------+
| | | | | | | | | |
|------------+------------| |------------+------------|
+--| | | +--| | |
| +-------------------------+ | +-------------------------+
| | | | | |
| | | | | |
| +-------------------------+ | +-------------------------+
+----------------+ +-----------------+
| | GLOBAL DESCRIPTOR TABLE
| | +-------------------------+
| | | |
| | | TASK DESCRIPTOR |
| | +-------------------------+
| | | | | | |
| +->|------------+------------|
+---->| | |--+
+-------------------------+ |
| | |
| | |
+-------------------------+ |
|
+-------------------------+ |
| | |
| | |
| | |
| TASK STATE | |
| SEGMENT | |
| | |
| | |
| | |
+-------------------------+<-+
Fig.7-6 Partially-Overlapping Linear Spaces
Figure 7-6. Partially-Overlapping Linear Spaces
TSSs PAGE FRAMES
+----------+
TASK A TSS PAGE DIRECTORIES PAGE TABLES | TASK A |
+----------+ +-----------+ +-----------+ +->| PAGE |
| | | | | | | +----------+
| | |-----------| |-----------| | +----------+
| | | | | PTE |--+ | TASK A |
| | |-----------| |-----------| +->| PAGE |
| | | | | PTE |--+ +----------+
|----------| |-----------| |-----------| +----------+
| PDBR |---->| PDE |---->| PTE |--+ | TASK A |
|----------| |-----------| +-----------+ +->| PAGE |
| | | PDE |--+ SHARED PT +----------+
+----------+ +-----------+ | +-----------+ +----------+
| | | | SHARED |
| |-----------| +->| PAGE |
| | | | +----------+
| |-----------| | +----------+
| | PTE |--+ | SHARED |
| |-----------| +->| PAGE |
|->| PTE |--+ +----------+
TASK B TSS | +-----------+ +----------+
+----------+ +-----------+ | | TASK B |
| | | | | +-->| PAGE |
| | |-----------| | +-----------+ | +----------+
| | | | | | | | +----------+
| | |-----------| | |-----------| | | TASK B |
| | | | | | | | +>| PAGE |
|----------| |-----------| | |-----------| | | +----------+
| PDBR |---->| PDE |--+ | PTE |-+ | PAGE FRAMES
|----------| |-----------| |-----------| |
| | | PDE |---->| PTE |---+
+----------+ +-----------+ +-----------+
TSSs PAGE DIRECTORIES PAGE TABLES