clui

Clear User Interrupt Flag

CLUI

Clears the User Interrupt Flag (UIF).

Details

Clears the User Interrupt Flag (UIF) in the UINTR register, preventing delivery of user-level interrupts to the current process. This is a privileged-equivalent instruction that requires the UINTR CPU feature and operates only in user mode; it has no effect on standard CPU flags or other processor state. Execution in a context where UINTR is unavailable causes a #UD exception.

Pseudocode Operation

UINTR.UIF ← 0

Example

CLUI

Encoding

Binary Layout

Format Legacy

Opcode F3 0F 01 EE

Extension UINTR

Operands

Reference (Intel® SDM)

Instruction Forms

Opcode	Instruction	Op/En	64/32-bit Mode	CPUID	Description
F3 0F 01 EE	CLUI	ZO	V/I	UINTR	Clear user interrupt flag; user interrupts blocked when user interrupt flag cleared.

Description

CLUI clears the user interrupt flag (UIF). Its effect takes place immediately: a user interrupt cannot be delivered on the instruction boundary following CLUI. An execution of CLUI inside a transactional region causes a transactional abort; the abort loads EAX as it would have had it been caused due to an execution of CLI.

Operation

UIF := 0;

Flags Affected

None.

Exceptions

Protected Mode Exceptions

#UD The CLUI instruction is not recognized in protected mode.

Real-Address Mode Exceptions

#UD The CLUI instruction is not recognized in real-address mode.

Virtual-8086 Mode Exceptions

#UD The CLUI instruction is not recognized in virtual-8086 mode.

Compatibility Mode Exceptions

#UD The CLUI instruction is not recognized in compatibility mode.

64-Bit Mode Exceptions

#UD If the LOCK prefix is used. If executed inside an enclave. If CR4.UINTR = 0. If CPUID.07H.00H:EDX.UINTR[5] = 0. CLUI—Clear User Interrupt Flag Vol. 2A 3-153