Appendix B
BIOS POST Checkpoint Codes
B-1 Uncompressed Initialization Codes
The uncompressed initialization checkpoint codes are listed in order of execution:
Checkpoint | Code Description | |
D0h | The NMI is disabled. Power on delay is starting. Next, the initialization code | |
checksum will be verified. | ||
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D1h | Initializing the DMA controller, performing the keyboard controller BAT test, | |
starting memory refresh and entering 4 GB flat mode next. | ||
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D3h | Starting memory sizing next. | |
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D4h | Returning to real mode. Executing any OEM patches and setting the Stack next. | |
| Passing control to the uncompressed code in shadow RAM at E000:0000h. The | |
D5h | initialization code is copied to segment 0 and control will be transferred to | |
| segment 0. | |
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B-2 Bootblock Recovery Codes
The bootblock recovery checkpoint codes are listed in order of execution:
Checkpoint | Code Description | |
E0h | The onboard floppy controller if available is initialized. Next, beginning the base | |
512 KB memory test. | ||
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E1h | Initializing the interrupt vector table next. | |
E2h | Initializing the DMA and Interrupt controllers next. | |
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E6h | Enabling the floppy drive controller and Timer IRQs. Enabling internal cache | |
memory. | ||
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Edh | Initializing the floppy drive. | |
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Efh | A read error occurred while reading the floppy drive in drive A:. | |
F0h | Next, searching for the AMIBOOT.ROM file in the root directory. | |
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F1h | The AMIBOOT.ROM file is not in the root directory. | |
F2h | Next, reading and analyzing the floppy diskette FAT to find the clusters occupied | |
by the AMIBOOT.ROM file. | ||
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F3h | Next, reading the AMIBOOT.ROM file, cluster by cluster. | |
F4h | The AMIBOOT.ROM file is not the correct size. | |
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F5h | Next, disabling internal cache memory. | |
FBh | Next, detecting the type of flash ROM. | |
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