A.2.4 Status Flags
The status flags provide some information about the result of the
arithmetic instructions. This information can be used by conditional
instructions (such a Jcc and CMOVcc) as well as by some of the other
instructions (such as ADC and INTO).
There are 6 status flags:
CF - Carry flag.
Set if an arithmetic operation generates a carry or a borrow out of
the most-significant bit of the result; cleared otherwise. This flag
indicates an overflow condition for unsigned-integer arithmetic. It is
also used in multiple-precision arithmetic.
PF - Parity flag.
Set if the least-significant byte of the result contains an even number
of 1 bits; cleared otherwise.
AF - Adjust flag.
Set if an arithmetic operation generates a carry or a borrow out of bit
3 of the result; cleared otherwise. This flag is used in binary-coded
decimal (BCD) arithmetic.
ZF - Zero flag.
Set if the result is zero; cleared otherwise.
SF - Sign flag.
Set equal to the most-significant bit of the result, which is the sign
bit of a signed integer. (0 indicates a positive value and 1 indicates a
negative value.)
OF - Overflow flag.
Set if the integer result is too large a positive number or too small
a negative number (excluding the sign-bit) to fit in the destination
operand; cleared otherwise. This flag indicates an overflow condition
for signed-integer (two's complement) arithmetic.