Browsing by Author "Shu-Wei"

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Butterfly match-line structure and search method implemented thereby
(2011-03-08)
Huang
;
Po-Tsang
;
Hwang
;
Wei
;
Chang
The present invention discloses a butterfly match-line structure and a search method implemented thereby, wherein the parallelism of the match lines is increased to shorten the search time, and a butterfly-type connection is used to reduce the power consumption and achieve the best energy efficiency. Via the butterfly-type connection, information can be reciprocally transmitted between the parallel match lines, which are independent originally. When a miss case occurs, more succeeding memory cells will not be compared but will be turned off. Thereby, the power consumption is reduced. Further, XOR-based conditional keepers are used to reduce the matching time and the power consumption. Besides, such a circuit is also used to shorten the delay time of the butterfly-type connection.
Stored don't-care based hierarchical search-line scheme
(2009-04-28)
Chang
;
Shu-Wei
;
Hwang
;
Wei
;
Chang
In the proposed stored don't-care hierarchical search-line scheme, a content-addressable memory (CAM) is divided into several blocks. Each block contains a plurality of local search-lines, a global search-line, a buffer and a memory memory cell. Data are stored in the blocks in order according to the length of the prefix. Data with the longest prefix is stored at the bottommost, and its don't-care state is used as the control signal of the buffer to control whether to transfer the data on the global search-line to the local search-line or not. The local search-line then transfer the value into the memory cell. There is no complex control circuit and extra storage device needed. Moreover, because the control signal directly comes from the don't-care state, power consumption on search-lines can be effectively reduced with no increase of search delay.