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CBI/CGI Technical Reference
Chassis PlansA-6
PORT 80 CODES The following codes are presented on Port 80H as the BIOS performs its reset procedure.
Code Description
Uncompressed Initialization Code Checkpoints:
D0
D1
D3
D4
D5
D6
D7
NMI is disabled. Power-on delay starting. Initialization code checksum to be verified
next.
Initializing DMA controller, performing keyboard controller BAT test, starting memory
refresh and entering 4GB flat mode next.
Starting memory sizing next.
Returning to real mode. Executing any OEM patches and setting stack next.
Passing control to uncompressed code in shadow RAM at E000:0000H. Initialization
code copied to segment 0 and control to be transferred to segment 0.
Control in segment 0. Checking if <Ctrl>+<Home> was pressed and verifying system
BIOS checksum. If <Ctrl>+<Home> was pressed or system BIOS checksum is bad,
going to checkpoint code E0H next. Otherwise, going to checkpoint code D7H.
Main BIOS runtime code to be decompressed and control to be passed to main BIOS
in shadow RAM.
Boot Block Recovery Code Checkpoints:
E0
E1
E2
E6
ED
EE
EF
F0
F1
F2
F3
F4
F5
FB
Onboard floppy controller initialized, if any. Beginning base 512KB memory test next.
Initializing interrupt vector table next.
Initializing DMA and interrupt controllers next.
Enabling floppy drive controller and timer IRQs. Enabling internal cache memory.
Initializing floppy drive.
Looking for floppy diskette in drive A:. Reading first sector of diskette.
Read error occurred while reading floppy drive in drive A:.
Searching for AMIBOOT.ROM file in root directory.
AMIBOOT.ROM file not in root directory.
Reading and analyzing floppy diskette FAT to find clusters occupied by
AMIBOOT.ROM file.
Reading AMIBOOT.ROM file next, cluster by cluster.
AMIBOOT.ROM file not correct size.
Disabling internal cache memory next.
Detecting type of flash ROM next.