86
I/O Address (hex)
Size
Assignment
03CC
1 byte
Add-in card; VGA
03CE-03CF
2 bytes
Add-in card; VGA
03D4-03D5
2 bytes
Add-in card; VGA
03DA
1 byte
Add-in card; VGA
03E8-03EF
8 bytes
COM 3
03F0-03F5
5 bytes
Floppy drive channel 1
03F6
1 byte
Primary IDE channel command
03F7 write
1 byte
Floppy drive channel 1 command
03F7 bit 7 read
1 bit
Floppy drive channel 1 disk change status
-03F7 bit 0-6 read
7 bits
Primary IDE channel status
03F8-03FF
8 bytes
COM 1
0CF8-0CFB
4 bytes
PCI configuration address registers (DW access)
0CFC-0CFF
4 bytes
PCI configuration data registers
FF00-FF07
8 bytes
IDE bus master registers
FFA0-FFA7
8 bytes
Primary IDE bus masters registers
FFA8-FFAF
8 bytes
Secondary IDE bus master registers
Memory Addresses
Memory Address
Range
Size
Description
0K-512 K
00000000-0007FFFF
512 K
DOS conventional memory
512K-640 K
00080000-0009FFFF
128 K
DOS conventional memory
640K-768 K
000A0000-000BFFFF
128 K
VGA memory and BIOS
768-896 K
000C0000-000DFFFF
128 K
Expansion card BIOS & buffer
896-1024 K
000E0000-000FFFFF
128 K
System BIOS
1024-15360 K
00100000-00EFFFFF
15.36 M
Main Memory
15.36 M-16.384 M
00F00000-00FFFFFF
1024 K
ISA memory hole (optional)
16.384 M-
Top of memory
01000000-
Top of memory
xxxx
Main memory
16.384 M-1048.576 M
01000000-3FFFFFFF
1032.192 M
Maximum memory allowable
1 G-(4 G-20 M)
04000000-FEBFFFFF
(3 G-20 M)
PCI/AGP memory
(4 G-20 M)- (4 G-19 M)
FEC00000-
FECFFFFF
1024 K
APIC configuration space
(4 G-19 M)-(4 G-18 M)
FED00000-
FEDFFFFF
1025 K
PCI/AGP memory