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Table 77.
Runtime Code Uncompressed in F000 Shadow RAM (continued)
Code
Description of POST Operation
40
Prepare the descriptor tables.
42
Enter virtual mode for memory test.
43
Enable interrupts for diagnostics mode.
44
Initialize data to check memory wrap-around at 0:0.
45
Data initialized. Check for memory wrap-around at 0:0, and find the total system memory size.
46
Memory wrap-around test done. Memory size calculation complete. Ready to write patterns to
test memory.
47
Pattern to be tested written in extended memory. Next, write patterns in base 640 K memory.
48
Patterns written in base memory. Find amount of memory below 1 MB.
49
Amount of memory below 1 MB found and verified. Find out amount of memory above 1 MB.
4B
Amount of memory above 1 MB found and verified. Check for soft reset and clear memory below
1 MB for soft reset. (If power on, go to check point 4Eh).
4C
Memory below 1 MB cleared. (Soft reset) Clear memory above 1 MB.
4D
Memory above 1 MB cleared. (Soft reset) Save the memory size. (Go to checkpoint 52h).
4E
Memory test started. (Not Soft Reset) Ready to display the first 64 K memory size.
4F
Memory size display started. This will be updated during memory test. Run sequential and
random memory test.
50
Memory testing/initialization below 1MB complete. Ready to adjust displayed memory size for
relocation/shadow.
51
Memory size display adjusted due to relocation/shadow. Memory test above 1 MB to follow.
52
Memory testing/initialization above 1 MB complete. Ready to save memory size information.
53
Memory size information is saved. Processor registers are saved. Ready to enter real mode.
54
Shutdown successful, processor in real mode. Ready to disable gate A20 line and disable
parity/NMI.
57
Successfully disabled A20 address line and parity/NMI. Ready to adjust memory size depending
on relocation/shadow.
58
Memory size adjusted for relocation/shadow. Ready to clear Hit <DEL> message.
59
Hit <DEL> message cleared. <WAIT...> message displayed. Ready to start DMA and Interrupt
Controller Test.
60
DMA Page Register Test passed. Ready to start DMA#1 Base Register Test.
62
DMA#1 Base Register Test passed. Ready to start DMA#2 Base Register Test.
65
DMA#2 Base Register Test passed. Ready to program DMA unit 1 and 2.
66
DMA unit 1 and 2 programming complete. Ready to initialize 8259 interrupt controller.
7F
Extended NMI sources enabling is in progress.
80
Keyboard test started. Clearing output buffer, checking for stuck key. Next, issue keyboard reset
command.
81
Keyboard reset error/stuck key found. Ready to issue keyboard controller interface test
command.
82
Keyboard controller interface test complete. Ready to write command byte and initialize circular
buffer.
83
Command byte written, global data initialization complete. Check for lock-key.
Error Messages and Beep Codes
continued
107
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