AMD AMD5K86 - Protected Virtual Interrupt (PVI) Extensions

1 8524BjO-Marl 996
AMDl1
AMD5136 Processor Technical Reference Manual
Table 3-6 compares the behavior of hardware and software
interrupts in various x86-processor operating modes. It also
shows which interrupt table is accessed: the Protected-mode
IDT or the Real- and Virtual-8086-mode IVT. The column head-
ings in this table include:
• PE-Protection Enable bit in CRO (bit 0)
• VM- Virtual-8086 Mode bit in EFLAGS (bit 17)
• VME- Virtual Mode Extensions bit in CR4 (bit 0)
• PVI-Protected-Mode Virtual Interrupts bit in CR4 (bit 1)
• IOPL-I10 Privilege Level bits in EFLAGS (bits 13-12)
• IRE-Interrupt Redirection Bit for a task, from the Inter-
rupt Redirection Bitmap (IRB) in the tasks TSS
• GP(O)-General-protection exception, with error code = 0
• IDT -Protected-Mode Interrupt Descriptor Table
• IVT-Real- and Virtual-8086 Mode Interrupt Vector Table
TABLE 3-6. Interrupt Behavior and Interrupt-Table Access
Mode
Interrupt
PE
VM
VME PVI IOPL IRB
GP(O)
IDT
IVT
Type
Real mode
Software
0 0 0
-
0
- -
-
3
Hardware 0 0
0
-
0
- -
-
3
Software
1 0 0
- - - -
3
-
286 Pro-
Hardware 1 0 0
3
tected mode
- - - -
-
Software 1 1 0
-
=3
-
No
3
-
Software 1 1
0
- <3 -
Yes 3
-
386 Virtual-
Hardware 1 1 0 No 3
8086 model
-
- - -
Software 1 1 1
0
-
0 No 3
Virtual-
Software 1
1 1
0
=3
1 No 3
-
8086 Mode
Software 1 1
1
0
<3
1
Yes
3
-
Extensions
(VME)l
Hardware 1 1
1
0
- -
No
3
-
Protected Software 1 0 1 1
- -
No 3
-
Virtual
Extensions
Hardware 1 0 1 1
- -
No 3
-
(PVI)
Notes:
1. All Virtual-BOB6 tasks run at CPL = 3.
-
Not applicable.
Control Register 4 (CR4) Extensions
J-2J