From: Stas Sergeev <stssppnn@yahoo.com>
To: linux-msdos@vger.kernel.org
Subject: Re: A20 Address line - XMS issue
Date: Sat, 07 Dec 2002 01:29:41 +0300 [thread overview]
Message-ID: <3DF124D5.5050405@yahoo.com> (raw)
Hello.
Bart Oldeman wrote:
> HIMEM.SYS might be able to
> run in DOSEMU if DOSEMU would implement int 0x15/0x87 to copy extended
> memory though.
It can't.
> HIMEM.SYS might be able to
> run in DOSEMU if DOSEMU would implement int 0x15/0x87 to copy extended
> memory though.
Real mode is an ultimate requirement
for himem to work. You can't set up
the Big Real Mode from within v86.
Here is the source:
http://honors.tntech.edu/~will/fileformat.virtualave.net/programming/himem/xm386.asm
Here is the relevant part:
---
mov bx, descRealBig - OurGDT ; Special 4Gb selector
lgdt qword ptr cs:[GDTPtr]
mov eax, cr0
or al,1
mov cr0, eax ; Go into Protected Mode
; NOTE: NMIs will kill us!!!
---
Both "lgdt" and "mov cr0" are priviledged.
next reply other threads:[~2002-12-06 22:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-06 22:29 Stas Sergeev [this message]
2002-12-06 22:46 ` A20 Address line - XMS issue Bart Oldeman
-- strict thread matches above, loose matches on Subject: below --
2002-12-07 0:31 Stas Sergeev
2002-12-07 0:38 ` Bart Oldeman
2002-12-06 17:30 Stas Sergeev
2002-12-06 14:53 S.Gopi
2002-12-06 15:01 ` Reinhard Karcher
2002-12-06 21:13 ` Bart Oldeman
2002-12-07 6:05 ` S.Gopi
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