Figures Fig.15
Fig.15-1 V86 Mode Address Formation
Figure 15-1. V86 Mode Address Formation
19 3 0
+---------------------------------+---------+
BASE | 16-BIT SEGMENT SELECTOR | 0 0 0 0 |
+---------------------------------+---------+
+
19 15 0
+---------+---------------------------------+
OFFSET | 0 0 0 0 | 16-BIT EFFECTIVE ADDRESS |
+---------+---------------------------------+
=
20 0
LINEAR +---------------------------------------------+
ADDRESS | X X X X X X X X X X X X X X X X X X X X X X |
+---------------------------------------------+
Fig.15-2 Entering and Leaving an 8086 Program
Figure 15-2. Entering and Leaving the 8086 Program
MODE TRANSITION DIAGRAM
+-----------+
TASK SWITCH | INITIAL |
+----------------| ENTRY |
| OR IRET +-----------+
|
v
+--------------+ INTERRUPT, EXCEPTION +-------------+
| 8086 PROGRAM |----------------------------->| V86 MONITOR |
| (V86 MODE) |<-----------------------------| (PROTECTED |
+--------------+ IRET | MODE) |
^ | +-------------+
| | | ^
| | | |
| | | |
| |TASK SWITCH +-------------------+ TASK SWITCH |
| +----------->| OTHER 80386 TASKS |<---------+ |
+--------------| (PROTECTED MODE) |-------------+
TASK SWITCH +-------------------+ TASK SWITCH
Fig.15-3 PL 0 Stack after Interrupt in V86 Task
Figure 15-3. PL 0 Stack after Interrupt in V86 Task
WITHOUT ERROR CODE WITH ERROR CODE
31 0 31 0
+--------------+<----+ +--------------+<----+
| |OLD GS | | | |OLD GS | |
|------+-------| SS:ESP |------+-------| SS:ESP
D O | |OLD FS | FROM TSS | |OLD FS | FROM TSS
I F |------+-------| |------+-------|
R | |OLD DS | | |OLD DS |
E E |------+-------| |------+-------|
C X | |OLD ES | | |OLD ES |
T P |------+-------| |------+-------|
I A | |OLD SS | | |OLD SS |
O N |--------------| |--------------|
N S | OLD ESP | | OLD ESP |
I |--------------| |--------------|
| O | OLD EFLAGS | | OLD EFLAGS |
| N |--------------| |--------------|
| | |OLD CS | NEW | |OLD CS |
v |--------------| SS:EIP |--------------|
| OLD EIP | | | OLD EIP | NEW
|--------------|<---+ |--------------| SS:EIP
| | | ERROR CODE | |
. . |--------------|<---+
. . | |
. . . .