1/14 Synthesis and Design of Parameter Extractors for Low-Power Pre-computation-Based Content-addressable Memory Using Gate- Block Selection Algorithm Jui-Yuan Hsieh and Shanq-Jang Ruan, Department of Electronic Engineering National Taiwan University of Science and Technology, 2008 IEEE Presenter: Cheng-Yeh Tsao
2/14 Outline Previous work and observation PB-CAM architecture 1’s count PB-CAM 15-bit parameter extractor of the 1’s count PB-CAM Block-XOR PB-CAM The number of data related to the same parameter and average probability for the 1’s count and the block-xor approaches Proposed approach Truth table and average number of comparison operations of basic logic gates for a 2-bit skew data Gate-block selection algorithm An example Experimental results Conclusions
3/14 PB-CAM architecture Memory organization of the PB-CAM. During the writing phase During the data searching operation
4/14 1’s count PB-CAM Conceptual view of the 1’s count PB-CAM.
5/14 15-bit parameter extractor of the 1’s count PB-CAM
6/14 Block-XOR PB-CAM 15–bit parameter extractor of the block–xor PB-CAM. The number of blocks is = 1 = 0
7/14 The number of data related to the same parameter and average probability for the 1’s count and the block-xor approaches 88% 4 x 8 x 8 x / (2048 x 16)
8/14 Proposed approach n-bit block diagram of the proposed parameter extractor architecture. N / 8 log 2 8
9/14 Truth table and average number of comparison operations of basic logic gates for a 2-bit skew data C avg = N 0 (1 - p)+ N 1 . p =
10/14 Gate-block selection algorithm AND OR XOR NAND NOR NXOR NAND NOR XOR ( C avg : The average of comparison operations)
11/14 An example (1/4) N 0 = 8N 1 = 8
12/14 An example (2/4) N 0 = 7N 1 = 9
13/14 An example (3/4) N 0 = 9N 1 = 7
14/14 An example (4/4)
15/14 Experimental results (1/2)
16/14 Experimental results (2/2) LG : Logic Gate FA : Full Adder
17/14 Conclusions Gate-block selection algorithm Saving the power by reducing the number of comparison operations Computing parameter bits only use three logic gate
18/14 END