An apparatus includes a controller and logic circuitry. The controller is configured to generate multiple single-bit logic values. Each single-bit logic value has one of (i) a first value indicating that a data packet has been written into a memory and (ii) a second value indicating that a data packet has been read from the memory. The logic circuitry is configured to serially stack the single-bit logic values. The apparatus could further include a shift memory bank configured to store the single-bit logic values. The logic circuitry can be configured to serially stack the single-bit logic values in the shift memory bank. For example, the logic circuitry can be configured to shift the single-bit logic values in the shift memory bank in different directions and insert one single-bit logic value into the memory bank at different ends depending on whether the one logic value has the first or second value.