Technical information

58 Chapter 4
14h Program chipset default values into chipset. Chipset default values
are MODBINable by OEM customers.
15h Reserved
16h Initial onboard clock generator if Early_Init_Onboard_Generator is
defined. See also POST 26h.
17h Reserved
18h Detect CPU information including brand, SMI type (Cyrix or Intel) and
CPU level (586 or 686).
19h Reserved
1Ah Reserved
1Bh Initial interrupts vector table. If no special specified, all H/W interrupts
are directed to SPURIOUS_INT_HDLR & S/W interrupts to
SPURIOUS_soft_HDLR.
1Ch Reserved
1Dh Initial EARLY_PM_INIT switch
1Eh Reserved
1Fh Load keyboard matrix (notebook platform)
20h Reserved
21h HPM Initialization (notebook platform)
22h Reserved
23h 1. Check validity of RTC value:
e.g. a value of 5Ah is an invalid value for RTC minute.
2. Load CMOS settings into BIOS stack. If Smos checksum fails,
use default value instead.
24h Prepare BIOS resource map for PCI & PnP use. If ESCD is valid,
take into consideration of the ESCD’s legacy information.
25h Early PCI Initialization:
• Enumerate PCI bus number
• Assign memory & I/O resource
• Search for a valid VGA device & VGA BIOS, and put it into C000:0
26h 1. If Early_Init_Onboard_Generator is not defined Onboard clock
generator initialization. Disable respective clock resource to
empty PCI & DIMM slots.
2. Init onboard PWM
3. Init onboard H/W monitor devices
27h Initialize INT 09 buffer
28h Reserved
29h 1. Program CPU internal MTRR (P6 & PII) for 0-640K memory
address.
2. Initialize the APIC for Pentium class CPU
3. Program early chipset according to CMOS setup. Example:
onboard IDE controller.
4. Measure CPU speed.
2Ah Reserved
2Bh Invoke Video BIOS
2Ch Reserved
2Dh 1. Initialize double-byte language font (Optional)
2. Put information on screen display, including Award title, CPU type,
CPU speed, full screen logo.
Checkpoint Description