Intel 253666-024US - Manual (Page 161)

Vol. 2A 3-115
INSTRUCTION SET REFERENCE, A-M
CMC—Complement Carry Flag
CMC—Complement Carry Flag
Description
Complements the CF flag in the EFLAGS register. CMC operation is the same in non-
64-bit modes and 64-bit mode.
Operation
EFLAGS.CF[bit 0]← NOT EFLAGS.CF[bit 0];
Flags Affected
The CF flag contains the complement of its original value. The OF, ZF, SF, AF, and PF
flags are unaffected.
Exceptions (All Operating Modes)
#UD If the LOCK prefix is used.
Opcode Instruction 64-Bit Mode Compat/
Leg Mode
Description
F5 CMC Valid Valid Complement CF flag.