Command: CMPSB - Compare String Operands
Arguments: none
Usage: CMPSB
Effects: CMPSW compares the byte at [DS:SI] or [DS:ESI] with byte at [ES:DI] or [ES:EDI], and sets the flags accordingly. It then increments or decrements (depending on the direction flag: increments if the flag is clear, decrements if it is set) SI and DI (or ESI and EDI).
Flags to be set: CF, OF, SF, ZF, AF, and PF