We have already discussed Cache line and TAG memory and various control flags in previous sections. To implement an efficient control circuit in hardware requires following approach. Implement a comparison circuit to match value in tag locations to the TAG field in address register. The control circuit needs to have an argument register to temporarily store TAG bits from address register.
When the output of above circuit is high then the corresponding bit in ‘match’ control flag is set to ‘1’. The complete circuit can be implemented simply by using AND gate, a buffer and a multiplexer for each cache line.