STC (Set Carry Flag)

Opcodes

Opcode Instruction Op/En 64-Bit Mode Compat/Leg Mode Description
F9 STC NP Valid Valid Set CF flag.

Instruction Operand Encoding

Op/En Operand 1 Operand 2 Operand 3 Operand 4
NP NA NA NA NA

Description

Sets the CF flag in the EFLAGS register. Operation is the same in all modes.

Operation

CF ← 1;

Flags Affected

The CF flag is set. The OF, ZF, SF, AF, and PF flags are unaffected.

Exceptions (All Operating Modes)

#UD

If the LOCK prefix is used.