Control Register 4 (CR4) Extensions
3-23
18524C/0—Nov1996
AMD-K5 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 CR0 (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—I/O Privilege Level bits in EFLAGS (bits 13–12)
■
IRB—Interrupt Redirection Bit for a task, from the Inter-
rupt Redirection Bitmap (IRB) in the tasks TSS
■
GP(0)—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
Type
PE
VM
VME
PVI
IOPL
IRB
GP(0)
IDT
IVT
Real mode
Software
0
0
0
—
0
—
—
—
✓
Hardware
0
0
0
—
0
—
—
—
✓
Protected mode
Software
1
0
0
—
—
—
—
✓
—
Hardware
1
0
0
—
—
—
—
✓
—
Virtual-8086
mode
1
Software
1
1
0
—
=
3
—
No
✓
—
Software
1
1
0
—
<
3
—
Yes
✓
—
Hardware
1
1
0
—
—
—
No
✓
—
Virtual-8086
Mode Exten-
sions (VME)
1
Software
1
1
1
0
—
0
No
—
✓
Software
1
1
1
0
=
3
1
No
✓
—
Software
1
1
1
0
<
3
1
Yes
✓
—
Hardware
1
1
1
0
—
—
No
✓
—
Protected Vir-
tual Extensions
(PVI)
Software
1
0
1
1
—
—
No
✓
—
Hardware
1
0
1
1
—
—
No
✓
—
Notes:
1. All Virtual-8086 tasks run at CPL = 3.
— Not applicable.
Содержание AMD-K5
Страница 1: ...AMD K5 Processor Technical Reference Manual TM...
Страница 10: ...x AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Страница 24: ...1 4 Overview AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Страница 54: ...2 30 Internal Architecture AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Страница 116: ...4 26 Performance AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Страница 356: ...6 44 System Design AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Страница 380: ...7 24 Test and Debug AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Страница 396: ...A 16 AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...
Страница 406: ...I 10 Index AMD K5 Processor Technical Reference Manual 18524C 0 Nov1996...