# Patent

## Title
Methods and systems for data analysis in a state machine

## Abstract

A device includes a match element that includes a first data input configured to receive a first result, wherein the first result is of an analysis performed on at least a portion of a data stream by an element of a state machine. The match element also includes a second data input configured to receive a second result, wherein the second result is of an analysis performed on at least a portion of the data stream by another element of the state machine. The match element further includes an output configured to selectively provide the first result or the second result.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. application Ser. No. 13/327,591, entitled “Methods and Systems for Data Analysis in a State Machine,” and filed Dec. 15, 2011, now U.S. Pat. No. 9,443,156 which issued on Sep. 13, 2016, the entirety of which is incorporated by reference herein for all purposes.


BACKGROUND
Field of Invention
Embodiments of the invention relate generally to electronic devices and, more specifically, in certain embodiments, to electronic devices with parallel finite state machines for pattern-recognition.
Description of Related Art
Complex pattern recognition can be inefficient to perform on a conventional von Neumann based computer. A biological brain, in particular a human brain, however, is adept at performing pattern recognition. Current research suggests that a human brain performs pattern recognition using a series of hierarchically organized neuron layers in the neocortex. Neurons in the lower layers of the hierarchy analyze “raw signals” from, for example, sensory organs, while neurons in higher layers analyze signal outputs from neurons in the lower levels. This hierarchical system in the neocortex, possibly in combination with other areas of the brain, accomplishes the complex pattern recognition that enables humans to perform high level functions such as spatial reasoning, conscious thought, and complex language.
In the field of computing, pattern recognition tasks are increasingly challenging. Ever larger volumes of data are transmitted between computers, and the number of patterns that users wish to identify is increasing. For example, spam or malware are often detected by searching for patterns in a data stream, e.g., particular phrases or pieces of code. The number of patterns increases with the variety of spam and malware, as new patterns may be implemented to search for new variants. Searching a data stream for each of these patterns can form a computing bottleneck. Often, as the data stream is received, it is searched for each pattern, one at a time. The delay before the system is ready to search the next portion of the data stream increases with the number of patterns. Thus, pattern recognition may slow the receipt of data.
Hardware has been designed to search a data stream for patterns, but this hardware often is unable to process adequate amounts of data in an amount of time given. Some devices configured to search a data stream do so by distributing the data stream among a plurality of circuits. The circuits each determine whether the data stream matches a portion of a pattern. Often, a large number of circuits operate in parallel, each searching the data stream at generally the same time. However, there has not been a system that effectively allows for performing pattern recognition in a manner more comparable to that of a biological brain. Development of such a system is desirable.



BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 illustrates an example of system having a state machine engine, according to various embodiments of the invention.
FIG. 2 illustrates an example of an FSM lattice of the state machine engine of FIG. 1, according to various embodiments of the invention.
FIG. 3 illustrates an example of a block of the FSM lattice of FIG. 2, according to various embodiments of the invention.
FIG. 4 illustrates an example of a row of the block of FIG. 3, according to various embodiments of the invention.
FIG. 5 illustrates an example of a Group of Two of the row of FIG. 4, according to various embodiments of the invention.
FIG. 6 illustrates an example of a finite state machine graph, according to various embodiments of the invention.
FIG. 7 illustrates an example of two-level hierarchy implemented with FSM lattices, according to various embodiments of the invention.
FIG. 8 illustrates an example of a method for a compiler to convert source code into a binary file for programming of the FSM lattice of FIG. 2, according to various embodiments of the invention.
FIG. 9 illustrates a state machine engine, according to various embodiments of the invention.
FIG. 10 illustrates an illustrates a second example of a row of the block of FIG. 3, according to various embodiments of the invention.
FIG. 11 illustrates an example of the match element of FIG. 10, according to various embodiments of the invention.
FIG. 12 illustrates a truth table corresponding to a multiplexer of FIG. 11, according to various embodiments of the invention.



DETAILED DESCRIPTION
Turning now to the figures, FIG. 1 illustrates an embodiment of a processor-based system, generally designated by reference numeral 10. The system 10 may be any of a variety of types such as a desktop computer, laptop computer, pager, cellular phone, personal organizer, portable audio player, control circuit, camera, etc. The system 10 may also be a network node, such as a router, a server, or a client (e.g., one of the previously-described types of computers). The system 10 may be some other sort of electronic device, such as a copier, a scanner, a printer, a game console, a television, a set-top video distribution or recording system, a cable box, a personal digital media player, a factory automation system, an automotive computer system, or a medical device. (The terms used to describe these various examples of systems, like many of the other terms used herein, may share some referents and, as such, should not be construed narrowly in virtue of the other items listed.)
In a typical processor-based device, such as the system 10, a processor 12, such as a microprocessor, controls the processing of system functions and requests in the system 10. Further, the processor 12 may comprise a plurality of processors that share system control. The processor 12 may be coupled directly or indirectly to each of the elements in the system 10, such that the processor 12 controls the system 10 by executing instructions that may be stored within the system 10 or external to the system 10.
In accordance with the embodiments described herein, the system 10 includes a state machine engine 14, which may operate under control of the processor 12. The state machine engine 14 may employ any one of a number of state machine architectures, including, but not limited to Mealy architectures, Moore architectures, Finite State Machines (FSMs), Deterministic FSMs (DFSMs), Bit-Parallel State Machines (BPSMs), etc. Though a variety of architectures may be used, for discussion purposes, the application refers to FSMs. However, those skilled in the art will appreciate that the described techniques may be employed using any one of a variety of state machine architectures.
As discussed further below, the state machine engine 14 may include a number of (e.g., one or more) finite state machine (FSM) lattices. Each FSM lattice may include multiple FSMs that each receive and analyze the same data in parallel. Further, the FSM lattices may be arranged in groups (e.g., clusters), such that clusters of FSM lattices may analyze the same input data in parallel. Further, clusters of FSM lattices of the state machine engine 14 may be arranged in a hierarchical structure wherein outputs from state machine lattices on a lower level of the hierarchical structure may be used as inputs to state machine lattices on a higher level. By cascading clusters of parallel FSM lattices of the state machine engine 14 in series through the hierarchical structure, increasingly complex patterns may be analyzed (e.g., evaluated, searched, etc.).
Further, based on the hierarchical parallel configuration of the state machine engine 14, the state machine engine 14 can be employed for pattern recognition in systems that utilize high processing speeds. For instance, embodiments described herein may be incorporated in systems with processing speeds of 1 GByte/sec. Accordingly, utilizing the state machine engine 14, data from high speed memory devices or other external devices may be rapidly analyzed for various patterns. The state machine engine 14 may analyze a data stream according to several criteria, and their respective search terms, at about the same time, e.g., during a single device cycle. Each of the FSM lattices within a cluster of FSMs on a level of the state machine engine 14 may each receive the same search term from the data stream at about the same time, and each of the parallel FSM lattices may determine whether the term advances the state machine engine 14 to the next state in the processing criterion. The state machine engine 14 may analyze terms according to a relatively large number of criteria, e.g., more than 100, more than 110, or more than 10,000. Because they operate in parallel, they may apply the criteria to a data stream having a relatively high bandwidth, e.g., a data stream of greater than or generally equal to 1 GByte/sec, without slowing the data stream.
In one embodiment, the state machine engine 14 may be configured to recognize (e.g., detect) a great number of patterns in a data stream. For instance, the state machine engine 14 may be utilized to detect a pattern in one or more of a variety of types of data streams that a user or other entity might wish to analyze. For example, the state machine engine 14 may be configured to analyze a stream of data received over a network, such as packets received over the Internet or voice or data received over a cellular network. In one example, the state machine engine 14 may be configured to analyze a data stream for spam or malware. The data stream may be received as a serial data stream, in which the data is received in an order that has meaning, such as in a temporally, lexically, or semantically significant order. Alternatively, the data stream may be received in parallel or out of order and, then, converted into a serial data stream, e.g., by reordering packets received over the Internet. In some embodiments, the data stream may present terms serially, but the bits expressing each of the terms may be received in parallel. The data stream may be received from a source external to the system 10, or may be formed by interrogating a memory device, such as the memory 16, and forming the data stream from data stored in the memory 16. In other examples, the state machine engine 14 may be configured to recognize a sequence of characters that spell a certain word, a sequence of genetic base pairs that specify a gene, a sequence of bits in a picture or video file that form a portion of an image, a sequence of bits in an executable file that form a part of a program, or a sequence of bits in an audio file that form a part of a song or a spoken phrase. The stream of data to be analyzed may include multiple bits of data in a binary format or other formats, e.g., base ten, ASCII, etc. The stream may encode the data with a single digit or multiple digits, e.g., several binary digits.
As will be appreciated, the system 10 may include memory 16. The memory 16 may include volatile memory, such as Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), Synchronous DRAM (SDRAM), Double Data Rate DRAM (DDR SDRAM), DDR2 SDRAM, DDR3 SDRAM, etc. The memory 16 may also include non-volatile memory, such as read-only memory (ROM), PC-RAM, silicon-oxide-nitride-oxide-silicon (SONOS) memory, metal-oxide-nitride-oxide-silicon (MONOS) memory, polysilicon floating gate based memory, and/or other types of flash memory of various architectures (e.g., NAND memory, NOR memory, etc.) to be used in conjunction with the volatile memory. The memory 16 may include one or more memory devices, such as DRAM devices, that may provide data to be analyzed by the state machine engine 14. Such devices may be referred to as or include solid state drives (SSD's), MultimediaMediaCards (MMC's), SecureDigital (SD) cards, CompactFlash (CF) cards, or any other suitable device. Further, it should be appreciated that such devices may couple to the system 10 via any suitable interface, such as Universal Serial Bus (USB), Peripheral Component Interconnect (PCI), PCI Express (PCI-E), Small Computer System Interface (SCSI), IEEE 1394 (Firewire), or any other suitable interface. To facilitate operation of the memory 16, such as the flash memory devices, the system 10 may include a memory controller (not illustrated). As will be appreciated, the memory controller may be an independent device or it may be integral with the processor 12. Additionally, the system 10 may include an external storage 18, such as a magnetic storage device. The external storage may also provide input data to the state machine engine 14.
The system 10 may include a number of additional elements. For instance, a complier 20 may be used to program the state machine engine 14, as described in more detail with regard to FIG. 8. An input device 22 may also be coupled to the processor 12 to allow a user to input data into the system 10. For instance, an input device 22 may be used to input data into the memory 16 for later analysis by the state machine engine 14. The input device 22 may include buttons, switching elements, a keyboard, a light pen, a stylus, a mouse, and/or a voice recognition system, for instance. An output device 24, such as a display may also be coupled to the processor 12. The display 24 may include an LCD, a CRT, LEDs, and/or an audio display, for example. They system may also include a network interface device 26, such as a Network Interface Card (NIC), for interfacing with a network, such as the Internet. As will be appreciated, the system 10 may include many other components, depending on the application of the system 10.
FIGS. 2-5 illustrate an example of a FSM lattice 30. In an example, the FSM lattice 30 comprises an array of blocks 32. As will be described, each block 32 may include a plurality of selectively couple-able hardware elements (e.g., programmable elements and/or special purpose elements) that correspond to a plurality of states in a FSM. Similar to a state in a FSM, a hardware element can analyze an input stream and activate a downstream hardware element, based on the input stream.
The programmable elements can be programmed to implement many different functions. For instance, the programmable elements may include state machine elements (SMEs) 34, 36 (shown in FIG. 5) that are hierarchically organized into rows 38 (shown in FIGS. 3 and 4) and blocks 32 (shown in FIGS. 2 and 3). To route signals between the hierarchically organized SMEs 34, 36, a hierarchy of programmable switching elements can be used, including inter-block switching elements 40 (shown in FIGS. 2 and 3), intra-block switching elements 42 (shown in FIGS. 3 and 4) and intra-row switching elements 44 (shown in FIG. 4).
As described below, the switching elements may include routing structures and buffers. A SME 34, 36 can correspond to a state of a FSM implemented by the FSM lattice 30. The SMEs 34, 36 can be coupled together by using the programmable switching elements as described below. Accordingly, a FSM can be implemented on the FSM lattice 30 by programming the SMEs 34, 36 to correspond to the functions of states and by selectively coupling together the SMEs 34, 36 to correspond to the transitions between states in the FSM.
FIG. 2 illustrates an overall view of an example of a FSM lattice 30. The FSM lattice 30 includes a plurality of blocks 32 that can be selectively coupled together with programmable inter-block switching elements 40. The inter-block switching elements 40 may include conductors 46 (e.g., wires, traces, etc.) and buffers 48 and 50. In an example, buffers 48 and 50 are included to control the connection and timing of signals to/from the inter-block switching elements 40. As described further below, the buffers 48 may be provided to buffer data being sent between blocks 32, while the buffers 50 may be provided to buffer data being sent between inter-block switching elements 40. Additionally, the blocks 32 can be selectively coupled to an input block 52 (e.g., a data input port) for receiving signals (e.g., data) and providing the data to the blocks 32. The blocks 32 can also be selectively coupled to an output block 54 (e.g., an output port) for providing signals from the blocks 32 to an external device (e.g., another FSM lattice 30). The FSM lattice 30 can also include a programming interface 56 to load a program (e.g., an image) onto the FSM lattice 30. The image can program (e.g., set) the state of the SMEs 34, 36. That is, the image can configure the SMEs 34, 36 to react in a certain way to a given input at the input block 52. For example, a SME 34, 36 can be set to output a high signal when the character ‘a’ is received at the input block 52.
In an example, the input block 52, the output block 54, and/or the programming interface 56 can be implemented as registers such that writing to or reading from the registers provides data to or from the respective elements. Accordingly, bits from the image stored in the registers corresponding to the programming interface 56 can be loaded on the SMEs 34, 36. Although FIG. 2 illustrates a certain number of conductors (e.g., wire, trace) between a block 32, input block 52, output block 54, and an inter-block switching element 40, it should be understood that in other examples, fewer or more conductors may be used.
FIG. 3 illustrates an example of a block 32. A block 32 can include a plurality of rows 38 that can be selectively coupled together with programmable intra-block switching elements 42. Additionally, a row 38 can be selectively coupled to another row 38 within another block 32 with the inter-block switching elements 40. A row 38 includes a plurality of SMEs 34, 36 organized into pairs of elements that are referred to herein as groups of two (GOTs) 60. In an example, a block 32 comprises sixteen (16) rows 38.
FIG. 4 illustrates an example of a row 38. A GOT 60 can be selectively coupled to other GOTs 60 and any other elements (e.g., a special purpose element 58) within the row 38 by programmable intra-row switching elements 44. A GOT 60 can also be coupled to other GOTs 60 in other rows 38 with the intra-block switching element 42, or other GOTs 60 in other blocks 32 with an inter-block switching element 40. In an example, a GOT 60 has a first and second input 62, 64, and an output 66. The first input 62 is coupled to a first SME 34 of the GOT 60 and the second input 62 is coupled to a second SME 34 of the GOT 60, as will be further illustrated with reference to FIG. 5.
In an example, the row 38 includes a first and second plurality of row interconnection conductors 68, 70. In an example, an input 62, 64 of a GOT 60 can be coupled to one or more row interconnection conductors 68, 70, and an output 66 can be coupled to one row interconnection conductor 68, 70. In an example, a first plurality of the row interconnection conductors 68 can be coupled to each SME 34, 36 of each GOT 60 within the row 38. A second plurality of the row interconnection conductors 70 can be coupled to only one SME 34, 36 of each GOT 60 within the row 38, but cannot be coupled to the other SME 34, 36 of the GOT 60. In an example, a first half of the second plurality of row interconnection conductors 70 can couple to first half of the SMEs 34, 36 within a row 38 (one SME 34 from each GOT 60) and a second half of the second plurality of row interconnection conductors 70 can couple to a second half of the SMEs 34, 36 within a row 38 (the other SME 34, 36 from each GOT 60), as will be better illustrated with respect to FIG. 5. The limited connectivity between the second plurality of row interconnection conductors 70 and the SMEs 34, 36 is referred to herein as “parity”. In an example, the row 38 can also include a special purpose element 58 such as a counter, a programmable Boolean logic element, look-up table, RAM, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a programmable processor (e.g., a microprocessor), or other element for performing a special purpose function.
In an example, the special purpose element 58 comprises a counter (also referred to herein as counter 58). In an example, the counter 58 comprises a 12-bit programmable down counter. The 12-bit programmable counter 58 has a counting input, a reset input, and zero-count output. The counting input, when asserted, decrements the value of the counter 58 by one. The reset input, when asserted, causes the counter 58 to load an initial value from an associated register. For the 12-bit counter 58, up to a 12-bit number can be loaded in as the initial value. When the value of the counter 58 is decremented to zero (0), the zero-count output is asserted. The counter 58 also has at least two modes, pulse and hold. When the counter 58 is set to pulse mode, the zero-count output is asserted during the clock cycle when the counter 58 decrements to zero, and at the next clock cycle the zero-count output is no longer asserted. When the counter 58 is set to hold mode the zero-count output is asserted during the clock cycle when the counter 58 decrements to zero, and stays asserted until the counter 58 is reset by the reset input being asserted.
In another example, the special purpose element 58 comprises Boolean logic. In some examples, this Boolean logic can be used to extract information from terminal state SMEs (corresponding to terminal nodes of a FSM, as discussed later herein) in FSM lattice 30. The information extracted can be used to transfer state information to other FSM lattices 30 and/or to transfer programming information used to reprogram FSM lattice 30, or to reprogram another FSM lattice 30.
FIG. 5 illustrates an example of a GOT 60. The GOT 60 includes a first SME 34 and a second SME 36 having inputs 62, 64 and having their outputs 72, 74 coupled to an OR gate 76 and a 3-to-1 multiplexer 78. The 3-to-1 multiplexer 78 can be set to couple the output 66 of the GOT 60 to either the first SME 34, the second SME 36, or the OR gate 76. The OR gate 76 can be used to couple together both outputs 72, 74 to form the common output 66 of the GOT 60. In an example, the first and second SME 34, 36 exhibit parity, as discussed above, where the input 62 of the first SME 34 can be coupled to some of the row interconnect conductors 68 and the input 64 of the second SME 36 can be coupled to other row interconnect conductors 70. In an example, the two SMEs 34, 36 within a GOT 60 can be cascaded and/or looped back to themselves by setting either or both of switching elements 79. The SMEs 34, 36 can be cascaded by coupling the output 72, 74 of the SMEs 34, 36 to the input 62, 64 of the other SME 34, 36. The SMEs 34, 36 can be looped back to themselves by coupling the output 72, 74 to their own input 62, 64. Accordingly, the output 72 of the first SME 34 can be coupled to neither, one, or both of the input 62 of the first SME 34 and the input 64 of the second SME 36.
In an example, a state machine element 34, 36 comprises a plurality of memory cells 80, such as those often used in dynamic random access memory (DRAM), coupled in parallel to a detect line 82. One such memory cell 80 comprises a memory cell that can be set to a data state, such as one that corresponds to either a high or a low value (e.g., a 1 or 0). The output of the memory cell 80 is coupled to the detect line 82 and the input to the memory cell 80 receives signals based on data on the data stream line 84. In an example, an input on the data stream line 84 is decoded to select one of the memory cells 80. The selected memory cell 80 provides its stored data state as an output onto the detect line 82. For example, the data received at the input block 52 can be provided to a decoder (not shown) and the decoder can select one of the data stream lines 84. In an example, the decoder can convert an 8-bit ACSII character to the corresponding 1 of 256 data stream lines 84.
A memory cell 80, therefore, outputs a high signal to the detect line 82 when the memory cell 80 is set to a high value and the data on the data stream line 84 corresponds to the memory cell 80. When the data on the data stream line 84 corresponds to the memory cell 80 and the memory cell 80 is set to a low value, the memory cell 80 outputs a low signal to the detect line 82. The outputs from the memory cells 80 on the detect line 82 are sensed by a detection cell 86.
In an example, the signal on an input line 62, 64 sets the respective detection cell 86 to either an active or inactive state. When set to the inactive state, the detection cell 86 outputs a low signal on the respective output 72, 74 regardless of the signal on the respective detect line 82. When set to an active state, the detection cell 86 outputs a high signal on the respective output line 72, 74 when a high signal is detected from one of the memory cells 82 of the respective SME 34, 36. When in the active state, the detection cell 86 outputs a low signal on the respective output line 72, 74 when the signals from all of the memory cells 82 of the respective SME 34, 36 are low.
In an example, an SME 34, 36 includes 256 memory cells 80 and each memory cell 80 is coupled to a different data stream line 84. Thus, an SME 34, 36 can be programmed to output a high signal when a selected one or more of the data stream lines 84 have a high signal thereon. For example, the SME 34 can have a first memory cell 80 (e.g., bit 0) set high and all other memory cells 80 (e.g., bits 1-255) set low. When the respective detection cell 86 is in the active state, the SME 34 outputs a high signal on the output 72 when the data stream line 84 corresponding to bit 0 has a high signal thereon. In other examples, the SME 34 can be set to output a high signal when one of multiple data stream lines 84 have a high signal thereon by setting the appropriate memory cells 80 to a high value.
In an example, a memory cell 80 can be set to a high or low value by reading bits from an associated register. Accordingly, the SMEs 34 can be programmed by storing an image created by the compiler 20 into the registers and loading the bits in the registers into associated memory cells 80. In an example, the image created by the compiler 20 includes a binary image of high and low (e.g., 1 and 0) bits. The image can program the FSM lattice 30 to operate as a FSM by cascading the SMEs 34, 36. For example, a first SME 34 can be set to an active state by setting the detection cell 86 to the active state. The first SME 34 can be set to output a high signal when the data stream line 84 corresponding to bit 0 has a high signal thereon. The second SME 36 can be initially set to an inactive state, but can be set to, when active, output a high signal when the data stream line 84 corresponding to bit 1 has a high signal thereon. The first SME 34 and the second SME 36 can be cascaded by setting the output 72 of the first SME 34 to couple to the input 64 of the second SME 36. Thus, when a high signal is sensed on the data stream line 84 corresponding to bit 0, the first SME 34 outputs a high signal on the output 72 and sets the detection cell 86 of the second SME 36 to an active state. When a high signal is sensed on the data stream line 84 corresponding to bit 1, the second SME 36 outputs a high signal on the output 74 to activate another SME 36 or for output from the FSM lattice 30.
In an example, a single FSM lattice 30 is implemented on a single physical device, however, in other examples two or more FSM lattices 30 can be implemented on a single physical device (e.g., physical chip). In an example, each FSM lattice 30 can include a distinct data input block 52, a distinct output block 54, a distinct programming interface 56, and a distinct set of programmable elements. Moreover, each set of programmable elements can react (e.g., output a high or low signal) to data at their corresponding data input block 52. For example, a first set of programmable elements corresponding to a first FSM lattice 30 can react to the data at a first data input block 52 corresponding to the first FSM lattice 30. A second set of programmable elements corresponding to a second FSM lattice 30 can react to a second data input block 52 corresponding to the second FSM lattice 30. Accordingly, each FSM lattice 30 includes a set of programmable elements, wherein different sets of programmable elements can react to different input data. Similarly, each FSM lattice 30, and each corresponding set of programmable elements can provide a distinct output. In some examples, an output block 54 from a first FSM lattice 30 can be coupled to an input block 52 of a second FSM lattice 30, such that input data for the second FSM lattice 30 can include the output data from the first FSM lattice 30 in a hierarchical arrangement of a series of FSM lattices 30.
In an example, an image for loading onto the FSM lattice 30 comprises a plurality of bits of information for configuring the programmable elements, the programmable switching elements, and the special purpose elements within the FSM lattice 30. In an example, the image can be loaded onto the FSM lattice 30 to program the FSM lattice 30 to provide a desired output based on certain inputs. The output block 54 can provide outputs from the FSM lattice 30 based on the reaction of the programmable elements to data at the data input block 52. An output from the output block 54 can include a single bit indicating a match of a given pattern, a word comprising a plurality of bits indicating matches and non-matches to a plurality of patterns, and a state vector corresponding to the state of all or certain programmable elements at a given moment. As described, a number of FSM lattices 30 may be included in a state machine engine, such as state machine engine 14, to perform data analysis, such as pattern-recognition (e.g., speech recognition, image recognition, etc.) signal processing, imaging, computer vision, cryptography, and others.
FIG. 6 illustrates an example model of a finite state machine (FSM) that can be implemented by the FSM lattice 30. The FSM lattice 30 can be configured (e.g., programmed) as a physical implementation of a FSM. A FSM can be represented as a diagram 90, (e.g., directed graph, undirected graph, pseudograph), which contains one or more root nodes 92. In addition to the root nodes 92, the FSM can be made up of several standard nodes 94 and terminal nodes 96 that are connected to the root nodes 92 and other standard nodes 94 through one or more edges 98. A node 92, 94, 96 corresponds to a state in the FSM. The edges 98 correspond to the transitions between the states.
Each of the nodes 92, 94, 96 can be in either an active or an inactive state. When in the inactive state, a node 92, 94, 96 does not react (e.g., respond) to input data. When in an active state, a node 92, 94, 96 can react to input data. An upstream node 92, 94 can react to the input data by activating a node 94, 96 that is downstream from the node when the input data matches criteria specified by an edge 98 between the upstream node 92, 94 and the downstream node 94, 96. For example, a first node 94 that specifies the character ‘b’ will activate a second node 94 connected to the first node 94 by an edge 98 when the first node 94 is active and the character ‘b’ is received as input data. As used herein, “upstream” refers to a relationship between one or more nodes, where a first node that is upstream of one or more other nodes (or upstream of itself in the case of a loop or feedback configuration) refers to the situation in which the first node can activate the one or more other nodes (or can activate itself in the case of a loop). Similarly, “downstream” refers to a relationship where a first node that is downstream of one or more other nodes (or downstream of itself in the case of a loop) can be activated by the one or more other nodes (or can be activated by itself in the case of a loop). Accordingly, the terms “upstream” and “downstream” are used herein to refer to relationships between one or more nodes, but these terms do not preclude the use of loops or other non-linear paths among the nodes.
In the diagram 90, the root node 92 can be initially activated and can activate downstream nodes 94 when the input data matches an edge 98 from the root node 92. Nodes 94 can activate nodes 96 when the input data matches an edge 98 from the node 94. Nodes 94, 96 throughout the diagram 90 can be activated in this manner as the input data is received. A terminal node 96 corresponds to a match of a sequence of interest by the input data. Accordingly, activation of a terminal node 96 indicates that a sequence of interest has been received as the input data. In the context of the FSM lattice 30 implementing a pattern recognition function, arriving at a terminal node 96 can indicate that a specific pattern of interest has been detected in the input data.
In an example, each root node 92, standard node 94, and terminal node 96 can correspond to a programmable element in the FSM lattice 30. Each edge 98 can correspond to connections between the programmable elements. Thus, a standard node 94 that transitions to (e.g., has an edge 98 connecting to) another standard node 94 or a terminal node 96 corresponds to a programmable element that transitions to (e.g., provides an output to) another programmable element. In some examples, the root node 92 does not have a corresponding programmable element.
When the FSM lattice 30 is programmed, each of the programmable elements can also be in either an active or inactive state. A given programmable element, when inactive, does not react to the input data at a corresponding data input block 52. An active programmable element can react to the input data at the data input block 52, and can activate a downstream programmable element when the input data matches the setting of the programmable element. When a programmable element corresponds to a terminal node 96, the programmable element can be coupled to the output block 54 to provide an indication of a match to an external device.
An image loaded onto the FSM lattice 30 via the programming interface 56 can configure the programmable elements and special purpose elements, as well as the connections between the programmable elements and special purpose elements, such that a desired FSM is implemented through the sequential activation of nodes based on reactions to the data at the data input block 52. In an example, a programmable element remains active for a single data cycle (e.g., a single character, a set of characters, a single clock cycle) and then becomes inactive unless re-activated by an upstream programmable element.
A terminal node 96 can be considered to store a compressed history of past events. For example, the one or more patterns of input data required to reach a terminal node 96 can be represented by the activation of that terminal node 96. In an example, the output provided by a terminal node 96 is binary, that is, the output indicates whether the pattern of interest has been matched or not. The ratio of terminal nodes 96 to standard nodes 94 in a diagram 90 may be quite small. In other words, although there may be a high complexity in the FSM, the output of the FSM may be small by comparison.
In an example, the output of the FSM lattice 30 can comprise a state vector. The state vector comprises the state (e.g., activated or not activated) of programmable elements of the FSM lattice 30. In an example, the state vector includes the states for the programmable elements corresponding to terminal nodes 96. Thus, the output can include a collection of the indications provided by all terminal nodes 96 of a diagram 90. The state vector can be represented as a word, where the binary indication provided by each terminal node 96 comprises one bit of the word. This encoding of the terminal nodes 96 can provide an effective indication of the detection state (e.g., whether and what sequences of interest have been detected) for the FSM lattice 30. In another example, the state vector can include the state of all or a subset of the programmable elements whether or not the programmable elements corresponds to a terminal node 96.
As mentioned above, the FSM lattice 30 can be programmed to implement a pattern recognition function. For example, the FSM lattice 30 can be configured to recognize one or more data sequences (e.g., signatures, patterns) in the input data. When a data sequence of interest is recognized by the FSM lattice 30, an indication of that recognition can be provided at the output block 54. In an example, the pattern recognition can recognize a string of symbols (e.g., ASCII characters) to; for example, identify malware or other information in network data.
FIG. 7 illustrates an example of hierarchical structure 100, wherein two levels of FSM lattices 30 are coupled in series and used to analyze data. Specifically, in the illustrated embodiment, the hierarchical structure 100 includes a first FSM lattice 30A and a second FSM lattice 30B arranged in series. Each FSM lattice 30 includes a respective data input block 52 to receive data input, a programming interface block 56 to receive programming signals and an output block 54.
The first FSM lattice 30A is configured to receive input data, for example, raw data at a data input block. The first FSM lattice 30A reacts to the input data as described above and provides an output at an output block. The output from the first FSM lattice 30A is sent to a data input block of the second FSM lattice 30B. The second FSM lattice 30B can then react based on the output provided by the first FSM lattice 30A and provide a corresponding output signal 102 of the hierarchical structure 100. This hierarchical coupling of two FSM lattices 30A and 30B in series provides a means to transfer information regarding past events in a compressed word from a first FSM lattice 30A to a second FSM lattice 30B. The information transferred can effectively be a summary of complex events (e.g., sequences of interest) that were recorded by the first FSM lattice 30A.
The two-level hierarchy 100 of FSM lattices 30A, 30B shown in FIG. 7 allows two independent programs to operate based on the same data stream. The two-stage hierarchy can be similar to visual recognition in a biological brain which is modeled as different regions. Under this model, the regions are effectively different pattern recognition engines, each performing a similar computational function (pattern matching) but using different programs (signatures). By connecting multiple FSM lattices 30A, 30B together, increased knowledge about the data stream input may be obtained.
The first level of the hierarchy (implemented by the first FSM lattice 30A) can, for example, perform processing directly on a raw data stream. That is, a raw data stream can be received at an input block 52 of the first FSM lattice 30A and the programmable elements of the first FSM lattice 30A can react to the raw data stream. The second level (implemented by the second FSM lattice 30B) of the hierarchy can process the output from the first level. That is, the second FSM lattice 30B receives the output from an output block 54 of the first FSM lattice 30A at an input block 52 of the second FSM lattice 30B and the programmable elements of the second FSM lattice 30B can react to the output of the first FSM lattice 30A. Accordingly, in this example, the second FSM lattice 30B does not receive the raw data stream as an input, but rather receives the indications of patterns of interest that are matched by the raw data stream as determined by the first FSM lattice 30A. The second FSM lattice 30B can implement a FSM that recognizes patterns in the output data stream from the first FSM lattice 30A.
FIG. 8 illustrates an example of a method 110 for a compiler to convert source code into an image configured to program a FSM lattice, such as lattice 30, to implement a FSM. Method 110 includes parsing the source code into a syntax tree (block 112), converting the syntax tree into an automaton (block 114), optimizing the automaton (block 116), converting the automaton into a netlist (block 118), placing the netlist on hardware (block 120), routing the netlist (block 122), and publishing the resulting image (block 124).
In an example, the compiler 20 includes an application programming interface (API) that allows software developers to create images for implementing FSMs on the FSM lattice 30. The compiler 20 provides methods to convert an input set of regular expressions in the source code into an image that is configured to program the FSM lattice 30. The compiler 20 can be implemented by instructions for a computer having a von Neumann architecture. These instructions can cause a processor 12 on the computer to implement the functions of the compiler 20. For example, the instructions, when executed by the processor 12, can cause the processor 12 to perform actions as described in blocks 112, 114, 116, 118, 120, 122, and 124 on source code that is accessible to the processor 12.
In an example, the source code describes search strings for identifying patterns of symbols within a group of symbols. To describe the search strings, the source code can include a plurality of regular expressions (regexs). A regex can be a string for describing a symbol search pattern. Regexes are widely used in various computer domains, such as programming languages, text editors, network security, and others. In an example, the regular expressions supported by the compiler include criteria for the analysis of unstructured data. Unstructured data can include data that is free form and has no indexing applied to words within the data. Words can include any combination of bytes, printable and non-printable, within the data. In an example, the compiler can support multiple different source code languages for implementing regexes including Perl, (e.g., Perl compatible regular expressions (PCRE)), PHP, Java, and NET languages.
At block 112 the compiler 20 can parse the source code to form an arrangement of relationally connected operators, where different types of operators correspond to different functions implemented by the source code (e.g., different functions implemented by regexes in the source code). Parsing source code can create a generic representation of the source code. In an example, the generic representation comprises an encoded representation of the regexs in the source code in the form of a tree graph known as a syntax tree. The examples described herein refer to the arrangement as a syntax tree (also known as an “abstract syntax tree”) in other examples, however, a concrete syntax tree or other arrangement can be used.
Since, as mentioned above, the compiler 20 can support multiple languages of source code, parsing converts the source code, regardless of the language, into a non-language specific representation, e.g., a syntax tree. Thus, further processing (blocks 114, 116, 118, 120) by the compiler 20 can work from a common input structure regardless of the language of the source code.
As noted above, the syntax tree includes a plurality of operators that are relationally connected. A syntax tree can include multiple different types of operators. That is, different operators can correspond to different functions implemented by the regexes in the source code.
At block 114, the syntax tree is converted into an automaton. An automaton comprises a software model of a FSM and can accordingly be classified as deterministic or non-deterministic. A deterministic automaton has a single path of execution at a given time, while a non-deterministic automaton has multiple concurrent paths of execution. The automaton comprises a plurality of states. In order to convert the syntax tree into an automaton, the operators and relationships between the operators in the syntax tree are converted into states with transitions between the states. In an example, the automaton can be converted based partly on the hardware of the FSM lattice 30.
In an example, input symbols for the automaton include the symbols of the alphabet, the numerals 0-9, and other printable characters. In an example, the input symbols are represented by the byte values 0 through 255 inclusive. In an example, an automaton can be represented as a directed graph where the nodes of the graph correspond to the set of states. In an example, a transition from state p to state q on an input symbol a, i.e. δ(p, a), is shown by a directed connection from node p to node q. In an example, a reversal of an automaton produces a new automaton where each transition p→q on some symbol a is reversed q→p on the same symbol. In a reversal, start state becomes a final state and the final states become start states. In an example, the language recognized (e.g., matched) by an automaton is the set of all possible character strings which when input sequentially into the automaton will reach a final state. Each string in the language recognized by the automaton traces a path from the start state to one or more final states.
At block 116, after the automaton is constructed, the automaton is optimized to, among other things, reduce its complexity and size. The automaton can be optimized by combining redundant states.
At block 118, the optimized automaton is converted into a netlist. Converting the automaton into a netlist maps each state of the automaton to a hardware element (e.g., SMEs 34, 36, other elements) on the FSM lattice 30, and determines the connections between the hardware elements.
At block 120, the netlist is placed to select a specific hardware element of the target device (e.g., SMEs 34, 36, special purpose elements 58) corresponding to each node of the netlist. In an example, placing selects each specific hardware element based on general input and output constraints for of the FSM lattice 30.
At block 122, the placed netlist is routed to determine the settings for the programmable switching elements (e.g., inter-block switching elements 40, intra-block switching elements 42, and intra-row switching elements 44) in order to couple the selected hardware elements together to achieve the connections describe by the netlist. In an example, the settings for the programmable switching elements are determined by determining specific conductors of the FSM lattice 30 that will be used to connect the selected hardware elements, and the settings for the programmable switching elements. Routing can take into account more specific limitations of the connections between the hardware elements that placement at block 120. Accordingly, routing may adjust the location of some of the hardware elements as determined by the global placement in order to make appropriate connections given the actual limitations of the conductors on the FSM lattice 30.
Once the netlist is placed and routed, the placed and routed netlist can be converted into a plurality of bits for programming of a FSM lattice 30. The plurality of bits are referred to herein as an image.
At block 124, an image is published by the compiler 20. The image comprises a plurality of bits for programming specific hardware elements of the FSM lattice 30. In embodiments where the image comprises a plurality of bits (e.g., 0 and 1), the image can be referred to as a binary image. The bits can be loaded onto the FSM lattice 30 to program the state of SMEs 34, 36, the special purpose elements 58, and the programmable switching elements such that the programmed FSM lattice 30 implements a FSM having the functionality described by the source code. Placement (block 120) and routing (block 122) can map specific hardware elements at specific locations in the FSM lattice 30 to specific states in the automaton. Accordingly, the bits in the image can program the specific hardware elements to implement the desired function(s). In an example, the image can be published by saving the machine code to a computer readable medium. In another example, the image can be published by displaying the image on a display device. In still another example, the image can be published by sending the image to another device, such as a programming device for loading the image onto the FSM lattice 30. In yet another example, the image can be published by loading the image onto a FSM lattice (e.g., the FSM lattice 30).
In an example, an image can be loaded onto the FSM lattice 30 by either directly loading the bit values from the image to the SMEs 34, 36 and other hardware elements or by loading the image into one or more registers and then writing the bit values from the registers to the SMEs 34, 36 and other hardware elements. In an example, the hardware elements (e.g., SMEs 34, 36, special purpose elements 58, programmable switching elements 40, 42, 44) of the FSM lattice 30 are memory mapped such that a programming device and/or computer can load the image onto the FSM lattice 30 by writing the image to one or more memory addresses.
Method examples described herein can be machine or computer-implemented at least in part. Some examples can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples. An implementation of such methods can include code, such as microcode, assembly language code, a higher-level language code, or the like. Such code can include computer readable instructions for performing various methods. The code may form portions of computer program products. Further, the code may be tangibly stored on one or more volatile or non-volatile computer-readable media during execution or at other times. These computer-readable media may include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memories (RAMs), read only memories (ROMs), and the like.
Referring now to FIG. 9, an embodiment of the state machine engine 14 is illustrated. As previously described, the state machine engine 14 is configured to receive data from a source, such as the memory 16 over a data bus. In the illustrated embodiment, data may be sent to the state machine engine 14 through a bus interface, such as a DDR3 bus interface 130. The DDR3 bus interface 130 may be capable of exchanging data at a rate greater than or equal to 1 GByte/sec. As will be appreciated, depending on the source of the data to be analyzed, the bus interface 130 may be any suitable bus interface for exchanging data to and from a data source to the state machine engine 14, such as a NAND Flash interface, PCI interface, etc. As previously described, the state machine engine 14 includes one or more FSM lattices 30 configured to analyze data. Each FSM lattice 30 may be divided into two half-lattices. In the illustrated embodiment, each half lattice may include 24K SMEs (e.g., SMEs 34, 36), such that the lattice 30 includes 48K SMEs. The lattice 30 may comprise any desirable number of SMEs, arranged as previously described with regard to FIGS. 2-5. Further, while only one FSM lattice 30 is illustrated, the state machine engine 14 may include multiple FSM lattices 30, as previously described.
Data to be analyzed may be received at the bus interface 130 and transmitted to the FSM lattice 30 through a number of buffers and buffer interfaces. In the illustrated embodiment, the data path includes data buffers 132, process buffers 134 and an inter-rank (IR) bus and process buffer interface 136. The data buffers 132 are configured to receive and temporarily store data to be analyzed. In one embodiment, there are two data buffers 132 (data buffer A and data buffer B). Data may be stored in one of the two data buffers 132, while data is being emptied from the other data buffer 132, for analysis by the FSM lattice 30. In the illustrated embodiment, the data buffers 132 may be 32 KBytes each. The IR bus and process buffer interface 136 may facilitate the transfer of data to the process buffer 134. The IR bus and process buffer 136 ensures that data is processed by the FSM lattice 30 in order. The IR bus and process buffer 136 may coordinate the exchange of data, timing information, packing instructions, etc. such that data is received and analyzed in the correct order. Generally, the IR bus and process buffer 136 allows the analyzing of multiple data sets in parallel through logical ranks of FSM lattices 30.
In the illustrated embodiment, the state machine engine 14 also includes a de-compressor 138 and a compressor 140 to aid in the transfer of the large amounts of data through the state machine engine 14. The compressor 140 and de-compressor 138 work in conjunction such that data can be compressed to minimize the data transfer times. By compressing the data to be analyzed, the bus utilization time may be minimized. Based on information provided by the compiler 20, a mask may be provided to the state machine engine 14 to provide information on which state machines are likely to be unused. The compressor 140 and de-compressor 138 can also be configured to handle data of varying burst lengths. By padding compressed data and including an indicator as to when each compressed region ends, the compressor 140 may improve the overall processing speed through the state machine engine 14. The compressor 140 and de-compressor 138 may also be used to compress and decompress match results data after analysis by the FSM lattice 30.
As previously described, the output of the FSM lattice 30 can comprise a state vector. The state vector comprises the state (e.g., activated or not activated) of programmable elements of the FSM lattice 30. Each state vector may be temporarily stored in the state vector cache memory 142 for further hierarchical processing and analysis. That is, the state of each state machine may be stored, such that the final state may be used in further analysis, while freeing the state machines for reprogramming and/or further analysis of a new data set. Like a typical cache, the state vector cache memory allows storage of information, here state vectors, for quick retrieval and use, here by the FSM lattice 30, for instance. Additional buffers, such as the state vector memory buffer, state vector intermediate input buffer 146 and state vector intermediate output buffer 148, may be utilized in conjunction with the state vector cache memory 142 to accommodate rapid analysis and storage of state vectors, while adhering to packet transmission protocol through the state machine engine 14.
Once a result of interest is produced by the FSM lattice 30, match results may be stored in a match results memory 150. That is, a “match vector” indicating a match (e.g., detection of a pattern of interest) may be stored in the match results memory 150. The match result can then be sent to a match buffer 152 for transmission over the bus interface 130 to the processor 12, for example. As previously described, the match results may be compressed.
Additional registers and buffers may be provided in the state machine engine 14, as well. For instance, the state machine engine 14 may include control and status registers 154. In addition, restore and program buffers 156 may be provided for using in programming the FSM lattice 30 initially, or restoring the state of the machines in the FSM lattice 30 during analysis. Similarly, save and repair map buffers 158 may also be provided for storage of save and repair maps for setup and usage.
FIG. 10 illustrates a second example of a row 38 similar to that discussed above with respect to FIG. 4. The row 38 may include programmable intra-row switching elements 44 and row interconnection/interconnect conductors 68, 70 (which can also be referred to as “row routing lines”, as described below).
Row 38 of FIG. 10 may include eight GOTS 60, a special purpose element 58, inputs 62, inputs 64, outputs 66, a match element 160, a plurality of row routing lines 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, 182, 184, 186, 188, 190, and 192 (collectively referred to hereafter as “row routing lines 162-192”), a special purpose element routing line 194, and a plurality of junction points 196.
Furthermore, in addition to being coupled to the illustrated SMEs 34, 36 in FIG. 11, the local routing matrix 172 may be coupled to all pairs of SMEs 34, 36 for the GOTs 60 in a particular row 38. Accordingly, the local routing matrix 172 may include programmable intra-row switching elements 44 and row interconnection/interconnect conductors 68, 70 (which can also be referred to as “row routing lines”, as described below).
The GOTS 60 and the special purpose element 58 illustrated in FIG. 10 are substantially similar to the GOTS 60 and the special purpose element 58 previously discussed with respect to FIG. 4. Accordingly, each GOT 60 receives an input 62, which may be a unified enable input, to operate as an enable signal for a detection cell 86 of a SME 34. Likewise, each GOT 60 also receives an input 64, which may also be a unified enable input, to operate as an enable signal for a detection cell 86 of a SME 36. These unified enable inputs 62, 64 may activate the detection cells 86 of the SMEs 34, 36 to output a respective result of an analysis performed by the respective SME, for example, a match in an analyzed data stream from a single SME 34, which may be utilized in conjunction with results from other SMEs 34, 36 to, for example, search for a pattern in a data stream. For example, unified enable input 62 and unified enable input 64 allow for selective activation of the SMEs 34, 36 so that results generated by each of the active SMEs 34, 36 may be utilized as part of an overall broader analysis of a data stream.
The result generated by an SME 34, 36 of a GOT 60 may be selectively provided from the GOT on output 66. In one embodiment, the possible outputs of the GOT 60 may include no output, an output of the first SME 34, i.e., output 72, an output of the second SME 36, i.e., output 74, or the output of the first SME 34 or the output of the second SME 36, i.e., output 72 or output 74. Thus, a GOT 60 may be programmed to output a selected result from a GOT 60. This programming may be accomplished, for example, based on a loaded image performed during an initial programming stage of the FSM lattice 30. Results from the GOTs 60 may be provided to a match element 160, which may operate to output a selected result generated from the row 38 for a given data stream search or a portion of a data stream search.
Additionally, row 38 may include row routing lines 162-192 (which may also be referred to as row interconnection/interconnect conductors). In the present embodiment, there are sixteen row lines 162-192 that are selectively coupleable to eight GOTS 60 and to the special purpose element 58. However, it should be appreciated that fewer or more row routing lines may be utilized in conjunction with the row 38.
Each of the row routing lines 162-192 may be utilized to provide enable signals for any of the SMEs 34, 36 of one or more GOTS 60 along inputs 62, 64. Accordingly, through use of these row routing lines 162-192, any particular detection cell 86 for any particular SME (e.g., SME 34) may be activated. This may be accomplished by selectively coupling (e.g., in accordance with a loaded image) the row routing lines 162-192 to unified enable inputs 62, 64 of the SMEs 34, 36. Moreover, to provide further flexibility in providing enable signals to the SMEs 34, 36, the row routing lines 162-192 may be divided up amongst two SMEs 34, 36 of a given GOT 60. For example, row routing lines 162, 164, 166, 168, 170, 172, 174, and 176, may be utilized to activate any of the SMEs 34, 36 in the row 38. For example, a GOT 60 may transmit an output 66 to the row routing line coupled thereto, for example, row routing line 162. This signal may be transmitted into the intra-block switch, where it may be routed, for example, on row routing line 164 to an additional GOT 60 in the row 38. Additionally, row routing lines 178, 182, 186, and 190 may activate SMEs 34 in row 38, for example, by receiving signals from intra-block switch 42, while row routing lines 180, 184, 188, and 192 may activate SMEs 36 in row 38 via, for example, signals received from the intra-block witch 42. In this manner, the overall number of row routing lines 162-192 may be reduced, while still allowing for overall flexibility and the ability to activate any detection cell 86 of any of the SMEs 34, 36 in a row 38.
As illustrated in FIG. 10, each of the row routing lines 162-192 includes a plurality of junction points 196. These junction points 196 may, for example, include the intra-row switching elements 44 of FIG. 3, since the junction points 196 may be utilized to selectively couple any GOT 60 to any other GOT 60, or any GOT 60 to any other element (e.g., a special purpose element 58) within the row 38 (or, for that matter, within another row and/or another block). However, these connections may be limited by available junction points 196. For example, each of row routing lines 162, 164, 166, 168, 170, 172, 174, and 176, may be utilized to activate any of the SMEs 34, 36 in the row 38. However, each of row routing lines 162, 164, 166, 168, 170, 172, 174, and 176 also are selectively coupleable to the output of a respective different one of the GOTs 60. For example, an output from any one of the GOTs 60 may only be provided from that GOT 60 on a respective one of the row routing lines 162, 164, 166, 168, 170, 172, 174, and 176 coupleable thereto. Thus, in one embodiment, because row routing lines 162, 164, 166, 168, 170, 172, 174, and 176 are coupleable to the outputs 66 of the GOTs 60, the row routing lines 162, 164, 166, 168, 170, 172, 174, and 176 may provide (e.g., drive-out) signals to the intra-block switch 42. In contrast, in one embodiment, row routing lines 178, 180, 182, 184, 186, 188, 190, and 192 may receive (e.g. be driven by) signals from the intra-block switch 42 that may be received from, for example, other rows 38 or blocks 32.
In addition to row routing lines 162-192, the row 38 may include a special purpose element routing line 194 coupled to a special purpose element 58. Similar to row routing lines 162, 164, 166, 168, 170, 172, 174, and 176, the special purpose routing line 194 may provide (e.g., drive-out) signals to the intra-block switch 42. In one embodiment, the special purpose element routing line 194 may also be coupleable to the match element 160. For example, if the special purpose element 58 comprises a counter, an output of the counter may be provided along the special purpose routing line 194. Similarly, if the special purpose element 58 includes a Boolean logic element, such as a Boolean cell, an output of the Boolean logic element may be provided along the special purpose routing line 194. Through the use of these special purpose elements, repetitive searches (e.g., find an element ten times) or cascaded searches (e.g., find elements x, y, and z) may be simplified into a single output that can be provided along the special purpose routing line 194 to either or both of the intra-block switch 42 and the match element 160.
A more detailed illustration of the match element 160 is presented in FIG. 11. As illustrated, the match element 160 may include four data inputs 198, 200, 202, and 204, two outputs, and six control inputs 210, 212, 214, 216, 218, and 220. Moreover, the match element may include two 2-to-1 multiplexers 222, 224. While 2-to-1 multiplexers 222, 224 are illustrated, it should be noted that other configurations such as a 3-to-1 multiplexer, a 4-to-1 multiplexer, or other elements may be utilized in place of the 2-to-1 multiplexers 224, 224 as desired, for example, to allow for flexibility in routing/output configurations or as silicon space allows.
In one embodiment, data input 198 of the match element 160 is coupled to row routing line 176, data input 200 is coupled to row routing line 174, data input 202 is coupled to special purpose routing line 194, and data input 204 is coupled to row routing line 168. Selection of these particular lines is illustrative only, and has been chosen to demonstrate flexibility in receiving output signals from the row 38. By choosing row routing line 168 and row routing line 176 as connecting to the match element 160, parity between the GOTs 60 can be established. For example, a result of a first analysis performed on at least a portion of a data stream by one GOT 60 in a first half of all the GOTs 60 (GOTs 60 zero through three) can be provided on routing line 168 to the match element 160 while a result of a second analysis performed on at least a portion of the data stream by another GOT 60 in a second half of all the GOTs 60 (GOTs 60 four through seven) can be provided on routing line 176 to the match element 160. Splitting the inputs 200, 204 this way can allow for reduced paths to provide results to the match element 160. Additionally, by receiving a result from the special purpose element 58 along special purpose routing line 194 at the match element 160, results of cascaded searches may be provided once to the match element 160. Finally, selection of row routing line 174 adds flexibility to the overall system of the row 38. However, as noted, these selections are merely illustrative.
As illustrated, the data inputs 198, 200 of the match element 160 may be provided to the 2-to-1 multiplexer 222, while the data inputs 202, 204 of the match element 160 may be provided to the 2-to-1 multiplexer 224. The 2-to-1 multiplexers 222, 224 may each also receive control signals from control inputs 210, 212, 214, 216, 218, and 220, which may, for example, be programmed based on a loaded image performed during an initial programming stage of the FSM lattice 30. In one embodiment, the 2-to-1 multiplexer 222 may receive a select signal S0 from control input 210, a select signal S1 from control input 212, and an output enable signal from control input 214. Similarly, the 2-to-1 multiplexer 224 may receive a select signal S0 from control input 216, a select signal S1 from control input 218, and an output enable signal from control input 220. The select signals S0, S1 may be utilized to select which of the data inputs are to be provided to output 206 and 208, respectively for transmitting results of a data search to, for example, output block 54. Furthermore, use of multiple select lines carrying the select signals S0, S1 may allow for each of the 2-to-1 multiplexers 222, 224 to be built without an inverter, thus reducing the area required to implement the 2-to-1 multiplexers 222, 224. However, in one embodiment, a single select line carrying a single select signal, e.g., S0, may be utilized.
Additionally, the output enable signal from control input 214 may be a clocking signal or other enable signal that allows for outputs 206 and 208 to be provided only when the signals on data inputs 198, 200, 202, and 204 are stable. FIG. 13 illustrates a truth table 226 that sets forth an example of how the select signal S0 from control input 210, a select signal S1 from control input 212 may programmably select the output 208 of the 2-to-1 multiplexer 224.
As shown in FIG. 13, a truth table 226 corresponding to the output 208 of the match element 160 is illustrated. It should be noted that the output 208 represented in the truth table 226 assumes that the output enable signal from control input 220 has been received at the 2-to-1 multiplexer 224. As illustrated in the truth table 226, when both the select signal S0 from control input 216 and the select signal S1 from control input 218 are low (i.e., 0), the output 208 of the 2-to-1 multiplexer 224 will be low. For example, no result from the row 38 will be provided from the match element 160. When the select signal S0 from control input 216 is high (i.e., 1) and the select signal S1 from control input 218 is low, the output 208 of the 2-to-1 multiplexer 224 will be the result on the row routing line 168. Conversely, when the select signal S0 from control input 216 is low and the select signal S1 from control input 218 is high, the output 208 of the 2-to-1 multiplexer 224 will be the result on the special purpose routing line 194. Finally, the condition whereby both the select signal S0 from control input 216 and the select signal S1 from control input 218 are high is forbidden. Accordingly, such a state is avoided during the programming of the match element 160. In this manner, match element 160 may programmably select no output, an output from a first data input 204 (the result on the row routing line 168) or an output from a second data input 202 (the result on the special purpose routing line 194). Furthermore, it should be noted that match element may operate in other programmable configurations not limited to the specific embodiment illustrated in FIG. 12.
While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.

## Claims

1. A device, comprising:
a match element comprising:
a first data input configured to be coupled to a first row routing line to receive a first result, wherein the first result comprises a match generated by an analysis of a first portion of a data stream by a first state machine element comprising: a first plurality of memory cells; and a first detection cell coupled to the first plurality of memory cells;
a second data input configured to be coupled to a second row routing line to receive a second result, wherein the second result comprises a second match generated by an analysis of a second portion of the data stream by a second state machine element comprising: a second plurality of memory cells; and a second detection cell coupled to the second plurality of memory cells; and
an output configured to selectively provide the first result or the second result.

2. The device of claim 1, wherein the match element is configured to selectively provide the first result or the second result via the output along a data path separate from any plurality of row routing lines comprising the first row routing line and the second row routing line.

3. The device of claim 2, wherein the match element is configured to selectively provide the first result or the second result via the output along the data path to an output block of a finite state machine lattice comprising the match element, the first state machine element, and the second state machine element.

4. The device of claim 1, wherein the match element comprises a first control input configured to receive a first control signal.

5. The device of claim 4, wherein the match element is configured to selectively provide the first result or the second result based on the first control signal.

6. The device of claim 4, wherein the match element comprises a second control input configured to receive an output enable signal.

7. The device of claim 6, wherein the match element is configured to selectively provide no result based on the output enable signal.

8. The device of claim 1, wherein the match element comprises a multiplexer.

9. A device, comprising:
a state machine comprising:
a plurality of blocks each comprising:
a plurality of rows, each comprising:
a first element, comprising: a first plurality of memory cells; and a first detection cell coupled to the first plurality of memory cells, wherein the first element is configured to generate a first result comprising a first match generated by an analysis of a first portion of a data stream;
a second element, comprising: a second plurality of memory cells; and a second detection cell coupled to the second plurality of memory cells, wherein the second element is configured to generate a second result comprising a second match generated by an analysis of a second portion of the data stream; and
a match element comprising:
 a first input configured to receive the first result;
 a second input configured to receive the second result; and
 an output configured to selectively provide the first result or the second result.

10. The device of claim 9, wherein the state machine comprises an output block coupled to a second state machine.

11. The device of claim 10, wherein the match element is configured to selectively provide the first result or the second result to the output block.

12. The device of claim 9, wherein the state machine comprises a third element comprising a third detection cell coupled to a third plurality of memory cells, wherein the third element is configured to generate a third result comprising a third match generated by an analysis of a third portion of the data stream.

13. The device of claim 12, wherein the state machine comprises a special purpose element configured to generate a fourth result based upon at least one of the first result, the second result, or the third result.

14. The device of claim 13, where the match element comprises:
a third input configured to receive the third result;
a fourth input configured to receive the fourth result; and
a second output configured to selectively provide the third result or the fourth result.

15. The device of claim 14, wherein the match element comprises:
a first multiplexer coupled to the first input, the second input, and the first output; and
a second multiplexer coupled to the third input, the fourth input, and the second output.

16. The device of claim 14, wherein the match element is configured to:
selectively provide the first result or the second result based upon a first control signal; and
selectively provide the third result or the fourth result based upon a second control signal.

17. A method, comprising:
receiving, at a first data input of a match element coupled to a first row routing line, a first result comprising a match generated by an analysis performed on at least a portion of a data stream by a first element of a state machine, wherein the first element of the state machine comprises: a first plurality of memory cells; and a first plurality of detection cells, wherein each detection cell of the first plurality of detection cells is coupled to a respective portion of the first plurality of memory cells;
receiving, at a second data input of the match element coupled to a second row routing line, a second result comprising a second match generated by an analysis performed on at least a portion of the data stream by a second element of the state machine, wherein the second element of the state machine comprises: a second plurality of memory cells; and a second plurality of detection cells, wherein each detection cell of the first plurality of detection cells is coupled to a respective portion of the second plurality of memory cells; and
selectively outputting from the match element the first result or the second result.

18. The method of claim 17, comprising receiving a first control signal at the match element.

19. The method of claim 18, wherein selectively outputting from the match element the first result or the second result is based on the control signal.

20. The method of claim 17, comprising:
receiving an output enable signal at the match element; and
selectively outputting no output from the match element based on the output enable signal.