LLDT, LGDT/LIDT, SGDT, SIDT, SLDT Instructions

Anyone here that might have used the following instructions...

LLDT "Load Local Descriptor Table Register"
LGDT/LIDT "Load Global/Interrupt Descriptor Table Register"
SGDT "Store Global Descriptor Table Register"
SIDT "Store Interrupt Descriptor Table Register"
SLDT "Store Local Descriptor Table Register"

1) Is there a good description anywhere ?
2) When and/or how might these instructions be used ?
a) Are they of any interest to high level programmers ?
b) Are they only used by the operating system (hardware
vendors) ?
3) Do you use these instructions ?
4) Are they actual registers ?
5) Anyone have a list of which processors support these
instructions ?

I ran across these while going through the Intel documentation
in relation to the BOUND instruction. If you could provide
some help relating BOUND into the definitions as well, that
would be great.

--
Jim Carlock
Post replies to the newsgroup, thanks.


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