Intel Motherboard Raptor AT Installation Manual page 75

Checkpoint
Code
Code copying to specific areas is done. Passing control
00h
to INT 19h boot loader next.
Table D-7 Bus Checkpoint Codes
The system BIOS passes control to different buses at the following
checkpoints:
Checkpoint
Code
Initializing the different bus system, static, and output
2Ah
devices, if present.
Initialized bus input, IPL, and general devices, if
38h
present.
39h Displaying bus initialization error messages, if any.
Initializing bus adaptor ROMs from C8000h through
95h
D8000h.
Table D-8 Additional Bus Checkpoints
While control is inside the different bus routines, additional
checkpoints are output to I/O port address 0080h as word to identify the
routines being executed.
These are word checkpoints. The low byte of checkpoint is the system
BIOS checkpoint where control is passed to the different bus routines.
The high byte of checkpoint indicates that the routine is being executed
in different buses. This information will not be shown on POST code
display because this device is 8-bit only. However, it can be seen in any
equipment connected to I/O port address 0080h.
Appendix D: Industrial Devices
Description
Description
65