Nvidia 754 specifications Appendix

Appendix

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

C-2