STUI

Set User Interrupt Flag

stableVMJITAOTinstruction

Encodings

OpcodeInstructionOp/En64-bitCompat/LegacyDescription
F3 0F 01 EFSTUIZOValidInvalidSet user interrupt flag.

Measured cost

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Description

STUI sets the user interrupt flag (UIF). Its effect takes place immediately; a user interrupt may be delivered on the instruction boundary following STUI. (This is in contrast with STI, whose effect is delayed by one instruction).

An execution of STUI inside a transactional region causes a transactional abort; the abort loads EAX as it would have had it been due to an execution of STI.

Operation

UIF := 1;

Flags affected

None.

Exceptions

Protected mode
#UDThe STUI instruction is not recognized in protected mode.
Real address mode
#UDThe STUI instruction is not recognized in real-address mode.
Virtual-8086 mode
#UDThe STUI instruction is not recognized in virtual-8086 mode.
Compatibility mode
#UDThe STUI instruction is not recognized in compatibility mode.
64-bit mode
#UDIf the LOCK prefix is used. If executed inside an enclave. If CR4.UINTR = 0. If CPUID.07H.00H:EDX.UINTR[5] = 0.

Sources