Match the string primitive to its purpose;

Load string byte :

[ Choose ] WriteString stosb cld setd ReadString loadsb lodsb storsb std

Store string byte :

[ Choose ] WriteString stosb cld setd ReadString loadsb lodsb storsb std

Clear direction flag :

[ Choose ] WriteString stosb cld setd ReadString loadsb lodsb storsb std

Set direction flag :

[ Choose ] WriteString stosb cld setd ReadString loadsb lodsb storsb std