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CLD—Clear Direction Flag
| Opcode | Instruction | Op/En | 64-bit Mode | Compat/Leg Mode | Description |
|---|---|---|---|---|---|
| FC | CLD | NP | Valid | Valid | Clear DF flag. |
Instruction Operand Encoding
| Op/En | Operand 1 | Operand 2 | Operand 3 | Operand 4 |
| NP | NA | NA | NA | NA |
Description
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.
Operation
DF ← 0;
Flags Affected
The DF flag is set to 0. The CF, OF, ZF, SF, AF, and PF flags are unaffected.
Exceptions (All Operating Modes)
#UD
If the LOCK prefix is used.