I'm trying to find a way to handle several bitfield cases that include optional, required, and not allowed positions. yy?nnn?y 11000001 ?yyy?nnn 01110000 nn?yyy?n 00011100 ?nnn?yyy 00000111 In these four cases, the ? indicates that the bit can be either 1 or 0 while y indicates a 1 is required and n indicates that a 0 is required. The bits to the left/right of the required bits can be anything and the remaining bits must be 0. Is there a masking method I can use to test if an input bit set satisfies one of these cases?