bit0: Underflow bit1: Overflow bit2: Divide by zero bit3: bit4: Illegal instruction (user program will only see zero, since cpu will halt) bit5: Processor Halted (user program will only see zero) bit6: Machine cycle count (user programs only see zero) bit7: Machine cycle count (user programs only see zero) After an add or multiply operation, bits 0 and 1 are interpreted like this: 00: no carry, the full result is in the accumulator 01: (can't happen) 10: there was an overflow or carry After a subtract or divide operation, bits 0 and 1 are interpreted like this: 00: no borrow, the full result is in the accumulator 01: underflow or borrow 10: (can't happen) After a compare operation, bits 0 and 1 are interpreted like this: 00: accumulator was equal too compared value 01: accumulator was less than compared value 10: accumulator was greater than compared value