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Chapter 4 107
3Ch Advanced configuration of chipset
registers
3Dh Load alternate registers with CMOS
values
42h Initialize interrupt vectors
45h POST device initialization
46h 2-1-2-3 Check ROM copyright notice
48h Check video configuration against CMOS
49h Initialize PCI bus and devices
4Ah Initialize all video adapters in system
4Bh QuietBoot start (optional)
4Ch Shadow video BIOS ROM
4Eh Display BIOS copyright notice
50h Display CPU type and speed
51h Initialize EISA board
52h Test keyboard
54h Set key click if enabled
58h 2-2-3-1 Test for unexpected interrupts
59h Initialize POST display service
5Ah Display prompt “Press F2 to enter
SETUP”
5Bh Disable CPU cache
5Ch Test RAM between 512 and 640 KB
60h Test extended memory
62h Test extended memory address lines
64h Jump to User Patch1
66h Configure advanced cache registers
67h Initialize Multi Processor APIC
68h Enable external and CPU caches
69h Setup System Management Mode (SMM)
area
6Ah Display external L2 cache size
6Bh Load custom defaults (optional)
6Ch Display shadow-area message
6Eh Display possible high address for UMB
recovery
70h Display error messages
72h Check for configuration errors
76h Check for keyboard errors
7Ch Set up hardware interrupt vectors
7Eh Initialize coprocessor if present
80h Disable onboard Super I/O ports and
IRQs
81h Late POST device initialization
Code Beeps POST Routine Description