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Ami post code, Ami post code -2, Ami post c – MSI IA-Q45 User Manual

Page 54

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4-2

System Resources

aMi poSt c

ode

Bootblock Initialization Code Checkpoints

The Bootblock initialization code sets up the chipset, memory and other

components before system memory is available. The following table de-

scribes the type of checkpoints that may occur during the bootblock initial-

ization portion of the BIOS:

Checkpoint

Description

Before D1

Early chipset initialization is done. Early super I/O initialization is done

including RTC and keyboard controller. NMI is disabled.

D1

Perform keyboard controller BAT test. Check if waking up from power

management suspend state. Save power-on CPUID value in scratch

CMOS.

D0

Go to flat mode with 4GB limit and GA20 enabled. Verify the bootblock

checksum.

D2

Disable CACHE before memory detection. Execute full memory sizing

module. Verify that flat mode is enabled.

D3

If memory sizing module not executed, start memory refresh and do

memory sizing in Bootblock code. Do additional chipset initialization.

Re-enable CACHE. Verify that flat mode is enabled.

D4

Test base 512KB memory. Adjust policies and cache first 8MB. Set

stack.

D5

Bootblock code is copied from ROM to lower system memory and con-

trol is given to it. BIOS now executes out of RAM.

D6

Both key sequence and OEM specific method is checked to determine

if BIOS recovery is forced. Main BIOS checksum is tested. If BIOS

recovery is necessary, control flows to checkpoint E0. See Bootblock

Recovery Code Checkpoints section of document for more informa-

tion.

D7

Restore CPUID value back into register. The Bootblock-Runtime in-

terface module is moved to system memory and control is given to it.

Determine whether to execute serial flash.

D8

The Runtime module is uncompressed into memory. CPUID informa-

tion is stored in memory.

D9

Store the Uncompressed pointer for future use in PMM. Copying Main

BIOS into memory. Leaves all RAM below 1MB Read-Write including

E000 and F000 shadow areas but closing SMRAM.

DA

Restore CPUID value back into register. Give control to BIOS POST

(ExecutePOSTKernel). See POST Code Checkpoints section of docu-

ment for more information.