Datasheet, Volume 2
53
Processor Configuration Registers
2.5.6
CC—Class Code Register
This register identifies the basic function of the device, a more specific sub-class, and a
register-specific programming interface.
2.5.7
HDR—Header Type Register
This register identifies the header layout of the configuration space. No physical
register exists at this location.
B/D/F/Type:
0/0/0/PCI
Address Offset:
9–Bh
Reset Value:
060000h
Access:
RO
Size:
24 bits
Bit
Attr
Reset
Value
RST/
PWR
Description
23:16
RO
06h
Uncore
Base Class Code (BCC)
This is an 8-bit value that indicates the base class code for the Host
Bridge device. This code has the value 06h, indicating a Bridge
device.
15:8
RO
00h
Uncore
Sub-Class Code (SUBCC)
This is an 8-bit value that indicates the category of Bridge into
which the Host Bridge device falls. The code is 00h indicating a
Host Bridge.
7:0
RO
00h
Uncore
Programming Interface (PI)
This is an 8-bit value that indicates the programming interface of
this device. This value does not specify a particular register set
layout and provides no practical use for this device.
B/D/F/Type:
0/0/0/PCI
Address Offset:
Eh
Reset Value:
00h
Access:
RO
Size:
8 bits
Bit
Attr
Reset
Value
RST/
PWR
Description
7:0
RO
00h
Uncore
PCI Header (HDR)
This field always returns 0 to indicate that the Host Bridge is a
single function device with standard header layout. Reads and
writes to this location have no effect.