- Index
- December 2023
CLD — Clear Direction Flag
Opcode | Instruction | Op/En | 64-bit Mode | Compat/Leg Mode | Description |
---|---|---|---|---|---|
FC | CLD | ZO | Valid | Valid | Clear DF flag. |
Instruction Operand Encoding ¶
Op/En | Operand 1 | Operand 2 | Operand 3 | Operand 4 |
---|---|---|---|---|
ZO | N/A | N/A | N/A | N/A |
Description ¶
Clears the DF flag in the EFLAGS register. When the DF flag is set to 0, string operations increment the index registers (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.