Nvidia 400 User Manual
Page 76
Appendix
C-2
18h
Detect CPU information including brand, SMI type (Cyrix or Intel) and
CPU level (586 or 686).
19-1Ah
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 CMOS checksum fails, use
default value instead.
3.
Prepare BIOS resource map for PCI & PnP use. If ESCD is valid,
take into consideration of the ESCD’s legacy information.
4.
Onboard clock generator initialization. Disable respective clock
resource to empty PCI & DIMM slots.
5.
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.
24-26h
Reserved
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.
5.
Invoke video BIOS.
2A-2Ch
Reserved
2Dh
1.
Initialize multi-language
2.
Put information on screen display, including Award title, CPU type,
CPU speed ….
2E-32h
Reserved
33h
Reset keyboard except Winbond 977 series Super I/O chips.
34-3Bh
Reserved
3Ch
Test 8254
3Dh
Reserved
3Eh
Test 8259 interrupt mask bits for channel 1.
3Fh
Reserved
40h
Test 8259 interrupt mask bits for channel 2.
41h
Reserved
42h
Reserved