CLD
Usage: CLD Modifies flags: DF
Clears the Direction Flag causing string instructions to increment the SI and DI index registers.
Clear Flags
CLC ; F8 [8086]
CLD ; FC [8086]
CLI ; FA [8086]
CLTS ; 0F 06 [286,PRIV]
These instructions clear various flags. CLC clears the carry flag; CLD clears the direction flag; CLI clears the interrupt flag (thus disabling interrupts); and CLTS clears the task-switched (TS) flag in CR0.
To set the carry, direction, or interrupt flags, use the STC, STD and STI instructions. To invert the carry flag, use CMC.
Example:
std
Do
mov al bl | and al 0F | add al '0'
On al > '9', add al 7
stosb | shr ebx 4
Do_Loop
cld