On 9/22/06, Thomas Petazzoni <thomas.petazzoni@xxxxxxxx> wrote:
Hi,
Le Thu, 21 Sep 2006 22:04:42 +0300,
borasahin@xxxxxxxxxxx a écrit :
> Any OS kernel like Linux...
Or bootloaders like Grub.
From http://www.win.tue.nl/~aeb/linux/kbd/A20.html:
If it is difficult, maybe impossible, to write a routine that will
enable A20 on all PCs, one might ask the BIOS to do so. Many recent
BIOS versions implement INT15 AX=240x functions, as follows:
INT 15 AX=2400 disable A20
INT 15 AX=2401 enable A20
INT 15 AX=2402 query status A20
INT 15 AX=2403 query A20 support (kbd or port 92)
Return:
If successful: CF clear, AH = 00h
On error: CF set, AH = status
Status: 01h keyboard controller is in secure mode
86h function not supported
For AX=2402 the status (0: disabled, 1: enabled) is returned in AL
For AX=2403 the status (bit 0: kbd, bit 1: port 92) is returned in BX
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