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Appendix A: AMIBIOS POST Checkpoint Codes
132
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.
High Byte
The high byte of these checkpoints includes the following information:
Bits Description
Bits 7-4 0000 Function 0. Disable all devices on the bus.
0001 Function 1. Initialize static devices on the bus.
0010 Function 2. Initialize output devices on the bus.
0011 Function 3. Initialize input devices on the bus.
0100 Function 4. Initialize IPL devices on the bus.
0101 Function 5. Initiate general devices on the bus.
0110 Function 6. Initialize error reporting on the bus.
0111 Function 7. Initialize add-on ROMs for all buses.
Bits 3-0 Specify the bus
0 Generic DIM Device Initialization Manager.
1 Onboard System devices.
2 ISA devices.
3 EISA devices.
4 ISA PnP devices.
5 PCI devices.
aa300.book Page 132 Tuesday, December 17, 2002 5:27 PM