gas/ld x86 16-bit 64kb limit and ominous "unreal mode"

[Zack Weinberg]

Denis Vlasenko <vda@ilport.com.ua> writes:

> On Wednesday 29 June 2005 16:58, Josef Angermeier wrote:
>> Now, i've by accident read about this ominous "unreal mode" (switching
>> from real mode to protected mode, changing the segment limits in the
>> cache and switching back) with which you can use 32-bit offset in
>> realmode (somehow). 
>
> There's more to it
>
> http://www.uwsg.iu.edu/hypermail/linux/kernel/0307.3/1132.html
>
> I was totally blown away how far madness can go :)

I would not count on anything other than the canonical real and
protected modes actually working.  Maybe "unreal" and "forreal" worked
on the original 80386, but the current chips don't work anything like
the way it did.

zw