32-bit address, 16-bit mode

[Ronald G Minnich]

I have a 32-bit address in %eax. What combination of operations can I do
to use that address to access high memory:

%esi?
%ebp?

Isn't there some combination of ops that will do this? after all, I can
use the 32-bit registers in 16-bit mode. How do I issue 32-bit addresses?

I think this is doable, am I wrong? do I have to go to bigreal mode?

ron