Abstract: A content addressable memory device (100) and method can have CAM blocks (102-0 to 102-29) organized in block sections (104-0 to 104-6). In an overlay mode of operation, an overlay engine (106) can access an algorithmic search (SPEAR) CAM (102-28 and 102-29) to generate overlay data set search keys (keyFIB<0> and <1>). Multiple data sets (e.g., FIB0, FIB1, ACL0) can be accommodated on the same CAM device by search key multiplexers (108-0 to 108-6) that selectively apply any of a number of data set search keys (keyACL<0>, keyFIB<0> and keyFIB<1>).

Abstract: A content addressable memory (CAM) device can include a plurality of CAM cells arranged in rows and columns to form multi-byte words. Each CAM cell can include a comparator circuit and one or more data storing circuits. Each comparator circuit can have one or more charge transfer paths arranged between a match line and a first voltage source node. Each data storing circuit can include a write circuit that provides a controllable impedance path between one or more charge transfer paths and a data storage node of the data storing circuit.

Abstract: A search engine method and apparatus can store and update status information for each entry of a content addressable memory (CAM) array, for a learn operation, or the like. A search engine can include a status memory block external to and independent of the CAM array. A status memory block (800) can include a number of memory sections (806-0 to 806-2) that each includes a number of bit locations for storing a free/not-free status of CAM entries in a hierarchical fashion. Corresponding control sections (808-0 to 808-2) can include priority encoders (812-0 to 812-2) that determine a first free element in a memory section for a next hierarchical level, as well as status aggregation logic (814-0 to 814-2) that can generate an aggregated status that is propagated to a previous hierarchical level.

Abstract: A search engine system can include at least one command decoder having search engine command input and at least one pipeline for propagating command data from the command decoder from a pipeline input to a pipeline output. The command data can be directed to targeted portions of a plurality of searchable entries. At least one current control circuit can issue dummy command data that bypasses the pipeline and activates non-targeted portions of the searchable entries.

Abstract: A frequency synthesis circuit includes a phase locked loop and an interpolator circuit. The phase locked loop circuit receives a reference clock and a feedback clock and generates an output clock with a frequency based on the reference clock and the feedback clock. An interpolator circuit is coupled in the feedback path of the phase locked loop circuit. An interpolator control circuit generates an interpolator control word that specifies a variable time delay for the interpolator circuit. The interpolator circuit receives the output clock, and generates the feedback clock by introducing a variable time delay in the output clock in accordance with the interpolator control word. The time variable delay varies the frequency of the output circuit. Embodiments for frequency synthesis circuits that include a spread spectrum frequency clock generator, frequency modulators, and a fixed frequency clock generator circuit are disclosed.

Abstract: A method and apparatus for multiple string searching using a ternary content addressable memory. The method includes receiving a text string having a plurality of characters and performing an unanchored search of a database of a stored patterns matching one or more characters of the text string using a state machine, wherein the state machine comprises a ternary content addressable memory (CAM) and wherein the performing comprises comparing a state and one of the plurality of characters with contents of a state field and a character field, respectively, stored in the ternary CAM. In various embodiments, one or more of the following search features may be supported: exact string matching, inexact string matching, single character wildcard matching, multiple character wildcard matching, case insensitive matching, parallel matching and rollback.

Abstract: An improved architecture for a network search engine (NSE) is disclosed herein as including an interface manager, one or more levels of a splitting engine, an array of data processing units (DPUs), and a cascade block. A method for using the improved NSE architecture to form an efficient pointer entry database is also provided. As described herein, the improved NSE architecture simultaneously provides high speed, search throughput, update rate and capacity, coupled with low power and fixed latency searches for all search key widths.

Abstract: A priority encoder circuit can include a number of sectional encoder circuits that each encode “m” inputs signals into sets of “P” encoder outputs, where m>p. Each sectional encoder circuit can also output a group indication signal representing the activation of any of the received m encoding input signals. Priority encoder logic can prioritized the group indication signals. A memory can include a different storage location accessed by each prioritized group indication signal.

Abstract: A frequency synthesis circuit includes a phase locked loop and an interpolator circuit. The phase locked loop circuit receives a reference clock and a feedback clock and generates an output clock with a frequency based on the reference clock and the feedback clock. An interpolator circuit is coupled in the feedback path of the phase locked loop circuit. An interpolator control circuit generates an interpolator control word that specifies a variable time delay for the interpolator circuit. The interpolator circuit receives the output clock, and generates the feedback clock by introducing a variable time delay in the output clock in accordance with the interpolator control word. The time variable delay varies the frequency of the output circuit. Embodiments for frequency synthesis circuits that include a spread spectrum frequency clock generator, frequency modulators, and a fixed frequency clock generator circuit are disclosed.

Abstract: A CAM cell (200) can include a compare section (206) and a configuration section (208). In a binary mode of operation, two compare data values can be driven on value lines VL1 to VL4 (216-0 to 216-3) for comparison against two stored data values. In a ternary mode of operation, one compare data value can driven on two of the value lines, while the other two value lines can be forced to a potential unrelated to a compare data value allowing for dynamic configuration between binary and ternary modes of operation.

Abstract: A method, apparatus, and storage medium product are provided for forming a forwarding database, and for using the formed database to more efficiently and quickly route packets of data across a computer network. The forwarding database is arranged into multiple sub-databases. Each sub-database is pointed to by a pointer within a pointer table. When performing a longest-match search of incoming addresses, a longest prefix matching algorithm can be used to find the longest match among specialized “spear prefixes” stored in the pointer table. After the longest spear prefixes are found, the pointer table will direct the next search within a sub-database pointed to by that spear prefix. Another longest-match search can be performed for database prefixes (or simply “prefixes”) within the sub-database selected by the pointer. Only the sub-database of interest will, therefore, be searched and all other sub-databases are not accessed.

Abstract: A content addressable memory (CAM) device can include a plurality CAM cell groups. The CAM cells of each group can be commonly connected to at least one local compare data line. A mask value circuit can be provided corresponding to each CAM cell group. Each mask value circuit can provide a mask value. At least a first logic circuit corresponding to each CAM cell group can have a first input coupled to at least a first global compare data line, a second input coupled to receive the mask value of the corresponding mask value circuit, and an output coupled to the corresponding at least first local compare data line.

Abstract: A low power content addressable memory (CAM) device. The CAM device receives an N-bit comparand value and, in response, activates less than N compare lines within the CAM device to compare each of the N bits of the comparand value with contents of CAM cells coupled to the N compare lines.

Abstract: An apparatus and method of transposing one or more bits in input data relative to other bits of the input data to form a compound for searching in a content addressable memory. The comparand may have one or more bits rearranged from their order appearing in the input data such that one or more bits from a first segment of the input data are replaced with, or substituted by, one or more bits from a second segment of the input data.

Abstract: A magnitude comparator circuit can include a bitwise comparison section that includes two passgates for each bit of two values that are compared to one another. The passgates can be enabled according to corresponding bit values of the two values.

Abstract: According to one embodiment, a content addressable memory (CAM) device (100) may include a number of segments (102 or 104). Search target compare circuits (110 and 112) can compare a target value TARGET to programmable information values (PIV0 and PIV1) associated with a particular segment (102 and 104). If a search target value TARGET matches a programmable information value (PIV0 and PIV1), search operations may be performed in a segment (102 or 104). If a search target value TARGET does not match a programmable information value, (PIV0 and PIV1), search operations may be prevented within a segment (102 or 104).

Abstract: An integrated circuit device for delivering power to a load includes a P-MOS power transistor, an N-MOS bypass transistor and a gate driver circuit. The P-MOS power transistor is coupled between a supply voltage node and a power output node of the integrated circuit device, and the N-MOS bypass transistor is coupled between the power output node and a reference node of the integrated circuit device. The gate driver circuit responds to a pulse-width-modulated (PWM) control signal by outputting an active-low drive-enable signal to a gate terminal of the P-MOS power transistor and an active-high bypass-enable signal to a gate terminal of the N-MOS bypass transistor during respective, non-overlapping intervals.

Abstract: A method of controlling a content addressable memory (CAM) device. A data structure is generated that specifies (i) a prioritized set of rules and (ii) storage locations within the CAM device for one or more match clauses of each of the rules. A new rule having a specified priority is recorded in the data structure. Candidate storage locations within the CAM device are identified within the CAM device for the match clauses of each of the rules having a lower priority than the new rule. The candidate storage locations are compared with the storage locations specified by the data structure. Each match clause for which the candidate storage location does not match the specified storage location is stored in the CAM device.

Abstract: An integrated circuit device for processing an access control list. The integrated circuit device includes a first content addressable memory (CAM) including a plurality of CAM blocks to generate respective match indices, each match index indicating a storage location within the corresponding CAM block of an entry that matches a search key. The integrated circuit device further includes a plurality of memory arrays to receive the match indices from the CAM blocks and to output respective lookup values from storage locations indicated by the match indices, each lookup value including information that indicates an action to be taken with respect to a packet used to obtain the search key and information that indicates a priority of the action relative to actions indicated by information in others of the lookup values.

Abstract: A content addressable memory device including a memory to store a searchable database, a search circuit, and a first-in-first-out storage circuit. The search circuit generates a plurality of address values that correspond to unoccupied storage locations within the memory, and the plurality of address values are queued within the first-in-first-out storage circuit to enable the address values to be read in succession by an external device.