String Related Instructions A string is nothing but a collection of ascii Characters codes. Many a time it require to perform some operation on strings such as copy a string, compare strings, concatenation of strings etc. 8086 has a powerful set of string related instructions and are DIscussed below: REP GROUP:   Instructions Description Example FLAG affected REP It is used as a prefix instruction. Repeat until CX=0, REP decrements CX in each loop REPE / REPZ Repeat the instruction until CX=0 or ZF is not equal to 1. REPE prefix will cause string instruction to be repeated, as long as compared bytes or words are equal or CX is not zero. GenerALly used with CMPS and  SCAN REPNE / REPNZ Repeat the following instruction until the compared string are not equal, and CX