Filter
Top Products
THE.
80286
INSTRUCTION SET
LAR-Load Access Rights Byte
Opcode
OF
02
Ir
FLAGS MODIFIED
Zero
Instruction
LAR
rW,ew
FLAGS UNDEFINED
None
OPERATION
Clocks
Description
14,mem=16
Load:
high(rw)= Access Rights byte, selector ew
LAR expects the second operand (memory
or
register word)
to
contain a selector.
If
the associated
descriptor
is
visible at the current privilege level and
at
the selector RPL, then the access rights byte
of the descriptor
is
loaded into the high byte of the first (register) operand, and the
low
byte
is
set
to
zero. The zero flag
is
set if the loading
was
performed (i.e., the selector index
is
within
the
table limit,
descriptor
DPL
:2:
CPL, and descriptor DPL
:2:
selector RPL); the zero flag
is
cleared otherwise.
Selector operands cannot cause protection exceptions.
PROTECTED MODE EXCEPTIONS
#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 EXCEPTION
INTERRUPT
6;
LAR
is
unrecognized
in
Real Address mode.
8-60