On 06-Dec-01 Nate Williams wrote:
>> > I saw an example of switching in real mode in linux' sources (it looks
>> > pretty clear) and thouhgt it is possible to do the same under FreeBSD.
>> > The problem is I'm absolutely lost in FreeBSD's physical memory management
>> > implementation (page tables and directory and so on).
>> 
>> That code is quite broken. You need to check out the ones I mentioned
>> earlier. All that the code does in the linux kernel is fail badly.
>> 
>> Actually there used to be in freebsd some really nice code for popping
>> into real mode and back again. It was to support calling BIOS for certain
>> things.
> 
> I believe the code is still there, and it's used for APM bios calls,
> if I remember correctly.

It uses VM86 mode, not real mode.  Going back and forth to real mode is too
expensive.

-- 

John Baldwin <[EMAIL PROTECTED]>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/

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