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X-Hacker.org- Assembly Language - <b>f000:fff0h far jmp to beginning of power-on self test (post)</b> http://www.X-Hacker.org [<<Previous Entry] [^^Up^^] [Next Entry>>] [Menu] [About The Guide]
F000:FFF0h               FAR JMP to Beginning of Power-On Self Test (POST)

 Length: 5 bytes

    Located at this address is a far jump to the beginning of the Power-On
    Self Test (POST).

  --------------------------------------------------------------------------

    See POST for more details on what it does. The reason this address is
    used for this purpose is that when the 8086 family of microprocessors
    receive power, the CS register is set to FFFFh and the IP register to
    0, which is exactly the same address as this address F000:FFF0h.

    If you wish to reboot (either warm or cold) a system, perform a far
    jump to this address. This will force the POST to take control, which
    will reboot the system. The POST looks at the word at address 0:472h
    to determine whether a warm boot or a cold boot should be performed.
    If the value at 0:472h is 1234h, then a warm boot is performed;
    otherwise the boot is cold.

See Also: 0:472h

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