2 ms·
I wonder what happens when a 286 in protected mode flips PE back to 0, assuming sane values in seg regs etc. Do you end up in some kind of unreal mode, does it
by hyperman1 3y ago
I wonder what happens when a 286 in protected mode flips PE back to 0, assuming sane values in seg regs etc. Do you end up in some kind of unreal mode, does it lock up completely, or what happens?
- pwg 3y agoAccording to this post: https://retrocomputing.stackexchange.com/questions/219/80286-can-switch-from-real-mode-to-protected-mode-but-why-not-back https://retrocomputing.stackexchange.com/questions/219/80286... attempting to set the PE bit back to zero has no effect: > The CPU is put into protected mode by setting the PE bit in MSW using the LMSW or LOADALL instructions. Clearing the PE bit has no effect using either of those instructions, thus it is not possible to switch back to real mode.