x86 EFLAGS

EFLAGS table

Bit	Type /val.	Name	Abbreviation
1	S	Carry Flag	CF
2	0	Always clear	rsvd_2
3	S	Parity Flag	PF
4	1	Always set	rsvd_4
5	S	Auxiliary Carry Flag	AF
6	1	Always set	rsvd_6
7	S	Zero Flag	ZF
8	S	Sign Flag	SF
9	X	Trap Flag	TF
10	X	Interrupt Enable Flag	IF
11	C	Direction Flag	DF
12	S	Overflow Flag	OF
13	X	I/O Privilege Level	IOPL
14	X	Nested Task	NT
15	0	Always clear	rsvd_15
16	X	Resume Flag	RF
17	X	Virtual-8086 Mode	VM
18	X	Alignment Check / Access Control	AC
19	X	Virtual Interrupt Flag	VIF
20	X	Virtual Interrupt Pending	VIP
21	X	ID Flag	ID

C macro constants

#define X86_EFLAGS_CF 1         /* Carry Flag [S]                       */
#define X86_EFLAGS_rsvd_2 2     /* Always clear [1]                     */
#define X86_EFLAGS_PF 3         /* Parity Flag [S]                      */
#define X86_EFLAGS_rsvd_4 4     /* Always set [1]                       */
#define X86_EFLAGS_AF 5         /* Auxiliary Carry Flag [S]             */
#define X86_EFLAGS_rsvd_6 6     /* Always set [1]                       */
#define X86_EFLAGS_ZF 7         /* Zero Flag [S]                        */
#define X86_EFLAGS_SF 8         /* Sign Flag [S]                        */
#define X86_EFLAGS_TF 9         /* Trap Flag [X]                        */
#define X86_EFLAGS_IF 10        /* Interrupt Enable Flag [X]            */
#define X86_EFLAGS_DF 11        /* Direction Flag [C]                   */
#define X86_EFLAGS_OF 12        /* Overflow Flag [S]                    */
#define X86_EFLAGS_IOPL 13      /* I/O Privilege Level [X]              */
#define X86_EFLAGS_NT 14        /* Nested Task [X]                      */
#define X86_EFLAGS_rsvd_15 15   /* Always clear [1]                     */
#define X86_EFLAGS_RF 16        /* Resume Flag [X]                      */
#define X86_EFLAGS_VM 17        /* Virtual-8086 Mode [X]                */
#define X86_EFLAGS_AC 18        /* Alignment Check / Access Control [X] */
#define X86_EFLAGS_VIF 19       /* Virtual Interrupt Flag [X]           */
#define X86_EFLAGS_VIP 20       /* Virtual Interrupt Pending [X]        */
#define X86_EFLAGS_ID 21        /* ID Flag [X]                          */