x86 VERR/W vs Present bit?

Emulation of old PCs, PC hardware, or PC peripherals.

x86 VERR/W vs Present bit?

Postby superfury » 2019-2-05 @ 10:10

How does VERR and VERW handle non-present descriptors? Does it clear the zero flag in that case? Or is it ignored(that would be strange)? Nothing is documented about that.

https://pdos.csail.mit.edu/6.828/2012/r ... 6/VERR.htm

Edit: The documentation says it to be writable(VERW) or readable(VERR) and that it performs the same checks as loading it into a register and trying a read or write accordingly. So that means the Present(Valid in Bochs) must be accounted for(just not in LSL/LAR)?
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