119
AMIBIOS POST Checkpoint Codes
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. |
|
|
D1h | Initializing the DMA controller, performing the |
| keyboard controller BAT test, starting memory |
| refresh, and entering 4 GB flat mode next. |
|
|
D3h | Starting memory sizing next. |
|
|
D4h | Returning to real mode. Executing any OEM |
| patches and setting the stack next. |
|
|
D5h | Passing control to the uncompressed code in |
| shadow RAM at E000:0000h. The initialization code |
| is copied to segment 0 and control will be |
| transferred to segment 0. |
|
|
D6h | Control is in segment 0. Next, checking if <Ctrl> |
| <Home> was pressed and verifying the system BIOS |
| checksum. |
| If either <Ctrl> <Home> was pressed or the system |
| BIOS checksum is bad, next will go to checkpoint |
| code E0h. |
| Otherwise, going to checkpoint code D7h. |
|
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