A CAM includes a parity bit system for error detection. In one embodiment, in
each
CAM cell, the data portion has its own data parity bit while the status portion
has an independent status parity bit. The status parity bit is recalculated and
updated whenever a status bit in the entry is changed. In another embodiment, each
status bit is provided with a corresponding shadow status bit. Each status bit
and its corresponding shadow status bit is always loaded with the same data. In
this manner, every change 1-bit change to a status bit is made as two identical
1-bit changes to the status bit and its corresponding shadow status bit. The two
identical 1-bit changes are parity neutral, thereby permitting status changes without
requiring recomputing and saving a new parity.