User's Manual

inter
THE 80286 INSTRUCTION SET
If ES or OS is loaded with non-null selector:
AR byte must indicate data or readable code segment else #GP (selector)
If
data or non-conforming code, then both the RPL and the
CPL must be less than or equal to OPL in AR byte else #GP (selector)
Segment must be marked PRESENT else #NP (selector)
Load segment register with selector
Load segment register cache with descriptor
If ES or OS is loaded with a null selector:
Load segment register with selector
Clear valid
bit in cache
PROTECTED MODE EXCEPTIONS
If a segment register is being loaded, #GP, #SS, and #NP, as described in the listing above.
Otherwise, #SS(O) if the current top of stack is not within the stack segment.
#GP(O) if the destination is in a non-writable segment. #GP(O) for an illegal memory operand effective
address
in the CS, DS, or ES segments; #SS(O) for an illegal address in the SS segment.
REAL ADDRESS MODE EXCEPTIONS
Interrupt 13 for a word operand at offset OFFFFH.
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