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BIOS
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3.9 AMI BIOS Checkpoints
The Bootblock initialization code sets up the chipset, memory and other
components before system memory is available. The following table
describes the type of checkpoints that may occur during the bootblock
initialization portion of the BIOS
(Note) :
Checkpoint Description
Before D0
If boot block debugger is enabled, CPU cache-as-RAM
functionality is enabled at this point. Stack will be enabled
from this point.
D0
Early Boot Strap Processo (BSP) initialization like
microcode update, frequency and other CPU cirtical
initialization. Early chipset initialization is done.
D1
Early super I/O initialization is done including RTC and
keyboard controller. Serial port is enabled at this point if
needed for debugging. NMI is deisabled. Perfrom keyboard
controller BAT test. Save power-on CPUID value in scretch
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D2
Verify the boot block checksum. System will hang here if
checksum is bad.
D3
Disable CACHE before memory detection. Execute full
memory sizing module. If memory sizing module not
executed, start memory refresh and do memory sizing in
Boot block code. Do additional chipset initialization. Re-
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D4
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8MB. Set stack.
D5
Bootblock code is copied from ROM to lower system
memory and control is given to it. BIOS now executes out
of RAM. Copies compressed boot block code to memory
in right segments. Copies BIOS from ROM to RAM for
faster access. Perfroms main BIOS checksum and updates
recovery status accordingly.
3.9.1 Bootblock Initialization Code Checkpoints