The byte match function operates on a 2-byte array:

f( [A, X] ) = [ A, M ]

A is compared against a bit pattern. If it matches, M is 1; otherwise, M is 0. In either case, A passes through unchanged, while X is discarded.

The bit pattern consists of zeros, ones, and don’t-cares. Meaning, each bit of A, Ai, is either compared against a constant or it is ignored. For example, the following expression checks if all Ai are 1:

Each Ai column contains an inverter pair, which enables A to traverse unmodified. For an arbitrary constant, K, inverter pairs only exist in the columns where Ki is 1. For instance, the expression below checks if A is 0: