| Opcode | Instruction | Op/En | 64-bit Mode | Compat/Leg Mode | Description |
|---|---|---|---|---|---|
| FC | CLD | NP | Valid | Valid | Clear DF flag. |
| Op/En | Operand 1 | Operand 2 | Operand 3 | Operand 4 |
| NP | NA | NA | NA | NA |
Clears the DF flag in the EFLAGS register. When the DF flag is set to 0, string operations increment the index regis-ters (ESI and/or EDI). Operation is the same in all modes.
DF ← 0;
The DF flag is set to 0. The CF, OF, ZF, SF, AF, and PF flags are unaffected.
#UD
If the LOCK prefix is used.