64
Chapter 5
Checkpoint Code
Description
2Ch
All necessary processing before passing control to the video ROM is done.
Looking for the video ROM next and passing control to it.
2Dh
The video ROM has returned control to BIOS POST. Performing any
required processing after the video ROM had control.
2Eh
Completed post-video ROM test processing. If the EGA/VGA controller
is not found, performing the display memory read/write test next.
2Fh
The EGA/VGA controller was not found. The display memory read/write
test is about to begin.
30h
The display memory read/write test passed. Look for retrace checking
next.
31h
The display memory read/write test or retrace checking failed. Performing
the alternate display memory read/write test next.
32h
The alternate display memory read/write test passed. Looking for alternate
display retrace checking next.
34h
Video display checking is over. Setting the display mode next.
37h
The display mode is set. Displaying the power on message next.
38h
Initializing the bus input, IPL, and general devices next, if present. See page
71 for additional information.
39h
Displaying bus initialization error messages. See page 71 for additional
information.
3Ah
The new cursor position has been read and saved. Displaying the Hit
<DEL> message next.
40h
Preparing the descriptor tables next.
42h
The descriptor tables are prepared. Entering protected mode for the
memory test next.
43h
Entered protected mode. Enabling interrupts for diagnostics mode next.
44h
Interrupts enabled if the diagnostics switch is on. Initializing data to check
memory wraparound at 0:0 next.
45h
Data initialized. Checking for memory wraparound at 0:0 and finding the
total system memory size next.
46h
The memory wraparound test has completed. The memory size calculation
has been completed. Writing patterns to test memory next.
47h
The memory pattern has been written to extended memory. Writing
patterns to the base 640 KB memory next.
48h
Patterns written in base memory. Determining the amount of memory below
1 MB next.
49h
The amount of memory below 1 MB has been found and verified.
Determining the amount of memory above 1 MB memory next.
4Bh
The amount of memory above 1 MB has been found and verified.
Checking for a soft reset and clearing the memory below 1 MB for the soft
reset next. If this is a power on situation, going to checkpoint 4Eh next.
