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Intel 253666-024US User Manual

Page 509

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Vol. 2A 3-463

INSTRUCTION SET REFERENCE, A-M

IN—Input from Port

DEST ← SRC; (* Read from selected I/O port *)

FI;

ELSE (Real Mode or Protected Mode with CPL ≤ IOPL *)

DEST ← SRC; (* Read from selected I/O port *)

FI;

Flags Affected

None.

Protected Mode Exceptions

#GP(0)

If the CPL is greater than (has less privilege) the I/O privilege

level (IOPL) and any of the corresponding I/O permission bits in
TSS for the I/O port being accessed is 1.

#UD

If the LOCK prefix is used.

Real-Address Mode Exceptions

#UD

If the LOCK prefix is used.

Virtual-8086 Mode Exceptions

#GP(0)

If any of the I/O permission bits in the TSS for the I/O port being

accessed is 1.

#PF(fault-code)

If a page fault occurs.

#UD

If the LOCK prefix is used.

Compatibility Mode Exceptions

Same exceptions as in protected mode.

64-Bit Mode Exceptions

#GP(0)

If the CPL is greater than (has less privilege) the I/O privilege

level (IOPL) and any of the corresponding I/O permission bits in
TSS for the I/O port being accessed is 1.

#UD

If the LOCK prefix is used.