POST (hex)

Tanım

 CFh

 Test CMOS R/W functionality.

 C0h

 Early chipset initialization:

        -Disable shadow RAM

        -Disable L2 cache (socket 7 or below)

        -Program basic chipset registers

 C1h

 Detect memory

        -Auto-detection of DRAM size, type and ECC.

        -Auto-detection of L2 cache (socket 7 or below)

 C3h

 Expand compressed BIOS code to DRAM

 C5h

 Call chipset hook to copy BIOS back to E000 & F000 shadow

 RAM.

 0h1

 Expand the Xgroup codes locating in physical address 1000:0

 02h

 Reserved

 03h

 Initial Superio_Early_Init switch.

 04h

 Reserved

 05h

1. Blank out screen

2. Clear CMOS error flag

 06h

 Reserved

 07h

1. Clear 8042 interface

2. Initialize 8042 self-test

 08h

1. Test special keyboard controller for Winbond 977 series Super

    I/O chips.

2. Enable keyboard interface.

 09h

 Reserved

 0Ah

1.  Disable PS/2 mouse interface (optional).

2.  Auto detect ports for keyboard & mouse followed by a port & interface swap (optional).

3.  Reset keyboard for Winbond 977 series Super I/O chips.

 0Bh

 Reserved

 0Ch

 Reserved

 0Dh

 Reserved

 0Eh

 Test F000h segment shadow to see whether it is R/W-able or not. If

 test fails, keep beeping the speaker.

 0Fh

 Reserved

 10h

 Auto detect flash type to load appropriate flash R/W codes into the

 run time area in F000 for ESCD & DMI support.

 11h

 Reserved

 12h

 Use walking 1’s algorithm to check out interface in CMOS

 circuitry.  Also set real-time clock power status, and then check

 for override.

 13h

 Reserved

 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.

2.1.2. Load CMOS settings into BIOS stack. If CMOS 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.

3.2. Init onboard PWM

4.3. 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.

 2Eh

 Reserved

 2Fh

 Reserved

 30h

 Reserved

 31h

 Reserved

 32h

 Reserved

 33h

 Reset keyboard if Early_Reset_KB is defined e.g. Winbond 977

 series Super I/O chips.  See also POST 63h.

 34h

 Reserved

 35h

 Test DMA Channel 0

 36h

 Reserved

 37h

 Test DMA Channel 1.

 38h

 Reserved

 39h

 Test DMA page registers.

 3Ah

 Reserved

 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

 43h

 Test 8259 functionality.

 44h

 Reserved

 45h

 Reserved

 46h

 Reserved

 47h

 Initialize EISA slot

 48h

 Reserved

 49h

1.  Calculate total memory by testing the last double word of each 64K page.

2.  Program write allocation for AMD K5 CPU.

 4Ah

 Reserved

 4Bh

 Reserved

 4Ch

 Reserved

 4Dh

 Reserved

 4Eh

1.  Program MTRR of M1 CPU

2.  Initialize L2 cache for P6 class CPU & program CPU with proper cacheable range.

3.  Initialize the APIC for P6 class CPU.

4.  On MP platform, adjust the cacheable range to smaller one in case the cacheable ranges between each CPU are not identical.

 4Fh

 Reserved

 50h

 Initialize USB Keyboard & Mouse.

 51h

 Reserved

 52h

 Test all memory (clear all extended memory to 0)

 53h

 Clear password according to H/W jumper (Optional)

 54h

 Reserved

 55h

 Display number of processors (multi-processor platform)

 56h

 Reserved

 57h

1.  Display PnP logo

2.  Early ISA PnP initialization

      -Assign CSN to every ISA PnP device.

 58h

 Reserved

 59h

 Initialize the combined Trend Anti-Virus code.

 5Ah

 Reserved

 5Bh

 (Optional Feature)

 Show message for entering AWDFLASH.EXE from FDD

 (optional)

 5Ch

 Reserved

 5Dh

1.  Initialize Init_Onboard_Super_IO

2.  Initialize Init_Onbaord_AUDIO.

 5Eh

 Reserved

 5Fh

 Reserved

 60h

 Okay to enter Setup utility; i.e. not until this POST stage can users

 enter the CMOS setup utility.

 61h

 Reserved

 62h

 Reserved

 63h

 Reset keyboard if Early_Reset_KB is not defined.

 64h

 Reserved

 65h

 Initialize PS/2 Mouse

 66h

 Reserved

 67h

 Prepare memory size information for function call:

  INT 15h ax=E820h

 68h

 Reserved

 69h

 Turn on L2 cache

 6Ah

 Reserved

 6Bh

 Program chipset registers according to items described in Setup &

 Auto-configuration table.

 6Ch

 Reserved

 6Dh

1.  Assign resources to all ISA PnP devices.

2.  Auto assign ports to onboard COM ports if the corresponding item in Setup is set to “AUTO”.

 6Eh

 Reserved

 6Fh

1.  Initialize floppy controller

2.  Set up floppy related fields in 40:hardware.

 70h

 Reserved

 71h

 Reserved

 72h

 Reserved

 73h

 (Reserved

 74h

 Reserved

 75h

 Detect & install all IDE devices: HDD, LS120, ZIP, CDROM…..

 76h

 (Optional Feature)

 Enter AWDFLASH.EXE if:

    -AWDFLASH.EXE is found in floppy drive.

    -ALT+F2 is pressed.

 77h

 Detect serial ports & parallel ports.

 78h

 Reserved

 79h

 Reserved

 7Ah

 Detect & install co-processor

 7Bh

 Reserved

 7Ch

 Init HDD write protect.

 7Dh

 Reserved

 7Eh

 Reserved

 7Fh

 Switch back to text mode if full screen logo is supported.

     -If errors occur, report errors & wait for keys

     -If no errors occur or F1 key is pressed to continue:

wClear EPA or customization logo.

 80h

 Reserved

 81h

 Reserved

 82h

1.  Call chipset power management hook.

2.  Recover the text fond used by EPA logo (not for full screen logo)

3.  If password is set, ask for password.

 83h

 Save all data in stack back to CMOS

 84h

 Initialize ISA PnP boot devices

 85h

1.  USB final Initialization

2.  Switch screen back to text mode

 86h

 Reserved

 87h

 NET PC: Build SYSID Structure.

 88h

 Reserved

 89h

1.  Assign IRQs to PCI devices

2.  Set up ACPI table at top of the memory.

 8Ah

 Reserved

 8Bh

1.  Invoke all ISA adapter ROMs

2.  Invoke all PCI ROMs (except VGA)

 8Ch

 Reserved

 8Dh

1.  Enable/Disable Parity Check according to CMOS setup

2.  APM Initialization

 8Eh

 Reserved

 8Fh

 Clear noise of IRQs

 90h

 Reserved

 91h

 Reserved

 92h

 Reserved

 93h

 Read HDD boot sector information for Trend Anti-Virus code

 94h

1.  Enable L2 cache

2.  Program Daylight Saving

3.  Program boot up speed

4.  Chipset final initialization.

5.  Power management final initialization

6.  Clear screen & display summary table

7.  Program K6 write allocation

8.  Program P6 class write combining

 95h

 Update keyboard LED & typematic rate

 96h

1.  Build MP table

2.  Build & update ESCD

3.  Set CMOS century to 20h or 19h

4.  Load CMOS time into DOS timer tick

5.  Build MSIRQ routing table.

 FFh

 Boot attempt (INT 19h)