In a microprocessor command ADD B means?

ADD B in a microprocessor means to add the contents of the accumulator to the B register and store the result in the accumulator. Flags are set according to the result - Z if zero, C if an unsigned carry occurred, AC if a BCD carry occurred, N if the result is signed negative, O if the parity is odd, OV if a signed overflow occurred. Note that not every microprocessor has every flag listed.