CMC

Complement Carry Flag

stableVMJITAOTinstruction

Encodings

Measured cost

Flags named

• CF Carry
• PF Parity
• AF Auxiliary carry
• ZF Zero
• SF Sign
• OF Overflow

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

Sources

• This instruction in the Intel manual
• Latency and throughput per microarchitecture