Intel 64 and IA-32 Architectures Software Developers Manual Volume 2B, Instruction Set Reference, N-Z

4-138 Vol. 2B

INSTRUCTION SET REFERENCE, N-Z

RFLAGS ← Pop(); (* 64-bit pop *)

(* All non-reserved bits except IOPL, RF, VIP, and VIF can be

modified; IOPL, RF, VM, and all reserved bits are

unaffected; VIP and VIF are cleared. *)

FI;

ELSE (* OperandSize

= 16 *)

EFLAGS[15:0] ← Pop(); (* 16-bit pop *)

(* All non-reserved bits except IOPL can be modified; IOPL and all

reserved bits are unaffected. *)

FI;

ELSE (* In Virtual-8086 Mode *)

IF IOPL = 3

THEN IF OperandSize

= 32

THEN

EFLAGS ← Pop();

(* All non-reserved bits except VM, RF, IOPL, VIP, and VIF can be

modified; VM, RF, IOPL, VIP, VIF, and all reserved bits are unaffected. *)

ELSE

EFLAGS[15:0] ← Pop(); FI;

(* All non-reserved bits except IOPL can be modified;

IOPL and all reserved bits are unaffected. *)

ELSE (* IOPL < 3 *)

#GP(0); (* Trap to virtual-8086 monitor. *)

FI;

Flags Affected

All flags may be affected; see the Operation section for details.

Protected Mode Exceptions

#SS(0) If the top of stack is not within the stack segment.

#PF(fault-code) If a page fault occurs.

#AC(0) If an unaligned memory reference is made while the current

privilege level is 3 and alignment checking is enabled.

Real-Address Mode Exceptions

#SS If the top of stack is not within the stack segment.