## std - set direction flag

    CF = 1

The std instruction sets the direction flag (DF) to 1. The direction flag is used in the various string instructions to determine whether to decrement or increment rdi or rsi or both. If DF is 0 the string instructions decrement and if DF is 1 they increment. If you use std, you are supposed to clear DF before you return from your function using cld.

            std             ; set DF to 1

### flags: DF