System BIOS
BIOS Addresses
Chapter 3
73
BIOS Addresses
This section provides a summary of the main features of the HP system BIOS. This is
software that provides an interface between the computer hardware and the operating
system. For the procedure to update the system ROM firmware, see page 70.
System Memory Map
Reserved memory that accessory boards use must reside in the area from C8000h to
EFFFFh.
HP I/O Port Map (I/O Addresses Used By The System, if
configured)
You access peripheral devices, accessory devices, and system controllers through the
system I/O space, which isn’t located in system memory space. The 64KB of addressable
I/O space comprises 8-bit and 16-bit registers (called I/O ports) located in the various
0000 0000 - 0000 03FF Real-mode IDT
0000 0400 - 0000 04FF BIOS data area
0000 0500 - 0009 FC00 Used by operating system
0009 FC00 - 0009 FFFF Extended BIOS data area
000A_0000 - 000B_FFFF Video RAM or SMRAM (not visible unless
in SMM)
000C 0000 - 000C 7FFF Video ROM (VGA ROM)
000C 8000 - 000F FFFF Adapter ROM, RAM, memory-mapped
registers, BIOS
000E 0000-000F FFFF 128KB BIOS (Flash/Shadow)
0001 0000-000F FFFF Memory (1MB to 16MB)
0010 0000-001F FFFF Memory (16MB to 32MB)
0020 0000-003F FFFF Memory (32MB to 64MB)
0040 0000-007F FFFF Memory (64MB to 128MB)
0080 0000-7FFF FFFF Memory (128MB to 2GB)
FECO 0000 I/O APIC
FEEO 0000 Local APIC (each CPU)
FFF8 0000-FFFF FFFF 512KB BIOS (Flash)
