The instructions of the logic functions are: and not, or and xor. These act on the bits of their operators.
To make sure the result of the operations we revolve to the cmp and test instructions. The instructions used for the algebraic functions are: to subtract sub, to add, to multiply mul and to divide div. approximately all the comparison instructions are based on the information limited in the flag register. Usually the flags of this register which can be straightforwardly handled by the programmer are the data direction flag DF, used to define the operations about chains. One more one which can also be
handled is the IF flag by means of the sti and cli instructions, to activate and disable the interruptions.