Masking
As we know the MASJ is used to cover some part of our face which we want to hide and to show other part of the face which we want to show.
Similarly the masking is a process in assembly language programming by which the unwanted bits of any data can be hidden and only the required bits remain available.
AND operation may be used for this purpose. We choose a data byte called masking byte which has 0 in the position where bit are to hidden and I in the position where bit are to be shown.