This article discusses the flag register specific to the x86 architecture. For a general discussion about flag registers, see status register.

The FLAGS register is the status register in Intel x86 microprocessors that contains the current state of the processor. This register is 16-bits wide. Its successors, the EFLAGS and RFLAGS registers are 32-bits and 64-bits wide, respectively. The wider registers retain compatibility with their smaller predecessors.

Intel x86 FLAGS Register
Bit #	Abbreviation	Description	Category*
FLAGS
0	CF	Carry flag	S
1	1	Reserved
2	PF	Parity flag	S
3	0	Reserved
4	AF	Auxiliary flag	S
5	0	Reserved
6	ZF	Zero flag	S
7	SF	Sign flag	S
8	TP	Trap flag (single step)	X
9	IF	Interrupt enable flag	X
10	DF	Direction flag	C
11	OF	Overflow flag	S
12, 13	IOPL	I/O privilege level (286+ only)	X
14	NT	Nested task flag (286+ only)	X
15	0	Reserved
EFLAGS
16	RF	Resume flag (386+ only)	X
17	VM	Virtual 8086 mode flag (386+ only)	X
18	AC	Alignment check (486SX+ only)	X
19	VIF	Virtual interrupt flag (Pentium+)	X
20	VIP	Virtual interrupt pending (Pentium+)	X
21	ID	Identification (Pentium+)	X
22	0	Reserved
23	0	Reserved
24	0	Reserved
25	0	Reserved
26	0	Reserved
27	0	Reserved
28	0	Reserved
29	0	Reserved
30	0	Reserved
31	0	Reserved
RFLAGS
32-63	0	Reserved

S: Status flag
C: Control flag
X: System flag

See also

• x86
• x86 assembly language
• x86 instruction listings