Implementation of Multiple-Valued CAM Functions by LUT Cascades

In this paper, we introduce three types of multiplevalued content-addressable memories (CAMs): ordinary CAMs (CAMs), distance d CAMs, and *CAMs. Ordinary CAMs require an exact match, while *CAMs allow wildcard matches. In a distance d CAM, a match occurs even if at most d digits differ. Then, we define multiple-valued CAM functions represented by these CAMs. Next, we show an approach to realize each CAM function by an LUT cascade, which is a series connection of RAMs. Experimental results for both two-valued and multi-valued cases are shown.