A content addressable memory includes a priority encoder that is in
communication with an array of the content addressable memory cells to
receive match signals, and from the match signals generating an output
index signal in accordance with a priority sequence of the match signals.
The priority encoder has a plurality of input circuits to receive the
match signals from the CAM array. A priority setting circuit receives a
priority transformation signal indicating a priority index for
modification of the priority sequence. An encoding circuit is in
communication with the plurality of input circuits and the priority
setting circuit for generating the output index signal in accordance with
the priority sequence. The priority encoder circuit further includes an
enabling circuit for receiving an enabling signal. The enabling circuit
communicates the enabling signals to the encoding circuit, such that upon
deactivation of the enabling signal, the encoding circuit generates the
output signal in accordance with the priority sequence with no
modification by the priority setting circuit. The priority index
indicates a region of the content addressable memory exempted from
effective comparison. This allows the CAM array to be searched for
multiple matches of the comparand. The priority index thus is an index
address of the content addressable memory determined with a previous
search of the content addressable memory. The priority index is provided
to the priority setting circuit through a word line decoder of the array
of content addressable memory cells.