
56 THE x86 MICROPROCESSORS
is used as a count), it will fi nally become zero. At this instant, the zero fl ag gets set i.e., ZF = 1.
Another case is when two numbers are compared. Comparison is achieved by subtraction. If the
numbers compared are equal, the zero fl ag is set (ZF = 1) indicating equality of the operands.
Parity Flag (PF) e setting of this fl ag indicates the presence of an even number of bits in the
least signifi cant byte (lower 8 bits) of the destination. For example, after a particular arithmetic
or logic operation, if the destination contains the number 11100111, the parity fl ag is set to
indicate even parity. Even if the operation ...