Abstract: A combined adder for N logical bits to produce a sum from a first addend having N first addend bits and a second addend having N second addend bits. A least significant adder produces a segment sum of the least significant bits and a carry out. Segment adder pairs are used for each higher order of significant sums. One segment adder produces a segment sum portion, and the other produces an incremented segment sum portion. Carry logic associated with each segment is utilized with a multiplexer to select the incremented segment sum portion or the segment sum portion. The selected segment sum portions are assembled with a most significant carry out to produce the sum.

Abstract: A first event source generates a first indication of a first event which has occurred in the first event source, the first indication being one of a predefined set of indications corresponding to a plurality of event types. A second event source generates a second indication of a second event which has occurred in the second event source, the second indication being one of the predefined set of indications corresponding to the plurality of event types. First event selection circuitry responds to the first indication matching a selected event type of the plurality of event types to generate a first count signal and second event selection circuitry responds to the second indication matching the selected event type of the plurality of event types to generate a second count signal. Count circuitry increments a counter in response to either the first count signal or the second count signal.

Abstract: A computer identifies one or more privacy settings. The computer receives a query for information. The computer determines whether a response to the query satisfies the one or more privacy settings. If the computer determines that the response to the query does not satisfy the one or more privacy settings, the computer alters the response to satisfy the one or more privacy settings.

Abstract: A 4-input lookup table module including eight first-rank 2-input multiplexers, four second-rank multiplexers, two third-rank multiplexers, and one fourth-rank multiplexer, the first-rank through fourth-rank multiplexers forming a tree structure. A select input of the fourth-rank multiplexer is coupled to a first input node. Select inputs of the third-rank multiplexers are coupled to a second input node. Select inputs of a first and a second adjacent ones of the second rank 2-input multiplexers are electrically isolated from select inputs of a third and a fourth adjacent ones of the second rank 2-input multiplexers. Select inputs of a first through a fourth adjacent ones of the first rank 2-input multiplexers are electrically isolated from select inputs of a fifth through an eighth adjacent ones of the first rank 2-input multiplexers.

Abstract: A system for inhibiting operation of a vehicle-based device while the vehicle is in motion includes a motion sensor, a timer, and a time delay override switch in communication with a control circuit. The control circuit selectively outputs one or more enable and/or inhibit signals based on the states of the motion sensor and timer. The time delay override switch can be actuated to place the timer into a timed out state from a timing state.

Abstract: Techniques are disclosed relating to performing arithmetic operations to generate values for different related threads. In some embodiments, the threads are graphics threads and the values are operand locations. In some embodiments, an apparatus performs an arithmetic operation using first circuitry, on type value inputs for different threads that are encoded to represent values to be operated on by the first circuitry. In some embodiments, second arithmetic circuitry is configured to perform an arithmetic operation on an output of the first circuitry and an input (e.g., address information such as a base and an offset) that is common to the different threads and has a greater number of bits than the output of the first circuitry. In various embodiments, disclosed techniques may allow decoding of encoded values for different threads (which may reduce memory requirements relative to non-encoded values) with a shorter critical path and lower power consumption, e.g., relative to sequential decoding.

Abstract: A semiconductor device includes a first active region, a second active region, a first gate line disposed to overlap the first and second active regions, a second gate line disposed to overlap the first and second active regions, a first metal line electrically connecting the first and second gate lines and providing a first signal to both the first and second gate lines, a first contact structure electrically connected to part of the first active region between the first and second gate lines, a second contact structure electrically connected to part of the second active region between the first and second gate lines, and a second metal line electrically connected to the first and second contact structures and transmitting a second signal, wherein an overlapped region that is overlapped by the second metal line does not include a break region.

Abstract: A method comprises receiving a first N-bit unsigned number and a second N-bit unsigned number, receiving a control signal indicating a m-bit shifting operation and processing the first N-bit unsigned number, the second N-bit unsigned number and the control signal in an add-and-shift apparatus, wherein an addition/subtraction operation and the m-bit shifting operation are performed in parallel in the add-and-shift apparatus.

Abstract: A method comprises receiving an N-bit unsigned number and a control signal, in response to the control signal indicating an increment operation, increasing the N-bit unsigned number by 1 through an increment/decrement apparatus having (2m+3) levels of 2-input logic gates, wherein m is equal to log2(N) and in response to the control signal indicating a decrement operation, decreasing the N-bit unsigned number by 1 through the increment/decrement apparatus.

Abstract: An incrementor circuit and method for incrementing is provided that computes an output data word by increasing an input data word magnitude by one of several integer values. The incrementor circuit includes a mode increment signal circuit providing a designation of one of the integer values for increasing the input data word magnitude. A single constant incrementor is connected to the mode increment signal circuit and the input data word and provides an intermediate sum by selectively adding a constant to the input data word. A multiplex circuit logically combines selected input data word bit position values with the mode increment signal circuit designation forming logical bit position values and directs selected input data word bit position values, selected logical bit position values, and selected bit position values of the intermediate sum to form the output data word.

Abstract: A carry look-ahead adder includes an input stage to produce generate bits and propagate bits from input signals. An output stage produces output sums exclusively from the generate bits, the propagate bits and carry in bits.

Abstract: There is provided a video signal processing method for performing predetermined signal processing on an input video signal to transmit an output video signal in a form of a specified transmission format through a video signal line including invalid bit polarity setting processing to be performed by an invalid bit polarity setting unit, wherein, when there exists an invalid bit having no data corresponding to data making up the input video signal in the specified transmission format of the output video signal, to count the number of low and high levels of gray-level data of the input video signal to compare a numerical size between the number of low levels and the number of high levels for judgment and to set a polarity of the invalid bit based on the judgment result.

Abstract: Generalized parallel counter circuitry is configured from logic elements—e.g., on a programmable integrated circuit device. Each logic element includes a logic stage, an adder and an output stage. The logic stage includes logic units, and a logic stage selector for selectively outputting to an input of the adder at least one of (a) outputs of the logic units, and (b) a first logic unit output of another one of the logic elements, and for selectively outputting to the output stage one of (a) an output of the logic units, and (b) a first output of the adder. The output stage includes at least two outputs, an output selector for selectively outputting, to the at least two outputs, at least one of (a) a second output of the adder, and (b) an output of the logic stage selector.

Abstract: An incrementor circuit and method for incrementing is provided that computes an output data word by increasing an input data word magnitude by one of several integer values. The incrementor circuit includes a mode increment signal circuit providing a designation of one of the integer values for increasing the input data word magnitude. A single constant incrementor is connected to the mode increment signal circuit and the input data word and provides an intermediate sum by selectively adding a constant to the input data word. A multiplex circuit logically combines selected input data word bit position values with the mode increment signal circuit designation forming logical bit position values and directs selected input data word bit position values, selected logical bit position values, and selected bit position values of the intermediate sum to form the output data word.

Abstract: An incrementor circuit and method for incrementing is provided that computes an output data word by increasing an input data word magnitude by one of several integer values. The incrementor circuit includes a mode increment signal circuit providing a designation of one of the integer values for increasing the input data word magnitude. A single constant incrementor is connected to the mode increment signal circuit and the input data word and provides an intermediate sum by selectively adding a constant to the input data word. A multiplex circuit logically combines selected input data word bit position values with the mode increment signal circuit designation forming logical bit position values and directs selected input data word bit position values, selected logical bit position values, and selected bit position values of the intermediate sum to form the output data word.

Abstract: A counting method and a counter using an integrated circuit memory area, including at least one step of storage of partial values in several words of identical memory sizes, the result of the counting being obtained by arithmetically adding the values contained in the different words.

Abstract: An incrementor circuit and method for incrementing is provided that computes an output data word by increasing an input data word magnitude by one of several integer values. The incrementor circuit includes a mode increment signal circuit providing a designation of one of the integer values for increasing the input data word magnitude. A single constant incrementor is connected to the mode increment signal circuit and the input data word and provides an intermediate sum by selectively adding a constant to the input data word. A multiplex circuit logically combines selected input data word bit position values with the mode increment signal circuit designation forming logical bit position values and directs selected input data word bit position values, selected logical bit position values, and selected bit position values of the intermediate sum to form the output data word.

Abstract: A saturating count counts received event signals up to a first predetermined number. An overflow counter counts overflows up to a second predetermined number. The counter indicates overflow when the overflow count is non-zero and saturates and stops counting at a maximum count when the overflow count reaches the second predetermined number. The counter can be read via a register read operation. The sum of the sum of the first predetermined number of bits and the second predetermined number of bits being an integral multiple of 8 bits.

Abstract: An implementation-efficient, multiple-counter value hardware performance counter is disclosed. A hardware counter of one embodiment includes a memory array and a hardware incrementer. The array stores counter values that are indexable by an index constructed based at least on the number of events to which the counter values correspond. The index may be constructed as a concatenation of a number of bits binarily representing the number of events, and a number of bits binarily representing the number of qualifiers to the events. The incrementer reads the counter values from the array, increments the counter values, and writes the resulting counter values back into the array. The array may be divided into banks over which the counter values are stored, where each bank has a separate instance of the incrementer. Each bank may have a separate instance of the index that indexes only those counters stored in the bank.

Abstract: A recursive carry-select substitution operation is used to optimize the design of an incrementer and similar logic devices. A carry look-ahead incrementer features XOR gates in which the XOR gates in one or more MSBs of the incrementer can be pushed back by substituting an equivalent carry-select circuit, the carry-select circuit including a multiplexer. The push back operations occur until both inputs of the XOR gates are fed by inverters, allowing an entire stage of inverters to be eliminated in the circuit. Where a bit path includes a buffer comprising two inverters, the inverter size is selected so as to execute as a single stage. The result is a carry look-ahead incrementer in which a stage is eliminated.

Abstract: An implementation-efficient, multiple-counter value hardware performance counter is disclosed. A hardware counter of one embodiment includes a memory array and a hardware incrementer. The array stores counter values that are indexable by an index constructed based at least on the number of events to which the counter values correspond. The index may be constructed as a concatenation of a number of bits binarily representing the number of events, and a number of bits binarily representing the number of qualifiers to the events. The incrementer reads the counter values from the array, increments the counter values, and writes the resulting counter values back into the array. The array may be divided into banks over which the counter values are stored, where each bank has a separate instance of the incrementer. Each bank may have a separate instance of the index that indexes only those counters stored in the bank.

Abstract: A method for incrementing, decrementing or two's complementing a first string of bits includes generating an auxiliary string of bits as a function of the first string, and logically combining the auxiliary string with the first string to generate a corresponding output string. A least significant bit of the auxiliary string is independent from the bits of the first string, and any other bit of the auxiliary string. The method is particularly convenient for generating an overflow flag when the number to be output exceeds the representation interval. An overflow flag is generated by logically combining the most significant bits of the first and auxiliary strings.

Abstract: A fast incrementer using zero detection and an increment method thereof. The incrementer performs a logic combination on an operand, first logic state inclusion information for each b-bit group of the operand, flag information for each b-bit group of the operand, and an increment value, and outputs a whole increment value for the operand.

Abstract: A command for incrementing a numeric value is inputted by pressing a “2” key. A command for decrementing the numeric value is inputted by depressing an “8” key. At least one of a process for incrementing the numeric value by the amount of increment according to the length of time during which the “2” key is held down and a process for decrementing the numeric value by the amount of decrement according to the length of time during which the “8” key is held down is performed to determine a value to be input.

Abstract: An implementation-efficient, multiple-counter value hardware performance counter is disclosed. A hardware counter of one embodiment includes a memory array and a hardware incrementer. The array stores counter values that are indexable by an index constructed based at least on the number of events to which the counter values correspond. The index may be constructed as a concatenation of a number of bits binarily representing the number of events, and a number of bits binarily representing the number of qualifiers to the events. The incrementer reads the counter values from the array, increments the counter values, and writes the resulting counter values back into the array. The array may be divided into banks over which the counter values are stored, where each bank has a separate instance of the incrementer. Each bank may have a separate instance of the index that indexes only those counters stored in the bank.

Abstract: The invention is a Gray code counter that uses a carry chain to determine the state of each bit of the counter. An additional bit that toggles at every clock is used to originate the carry chain, and to determine the counter direction. Then, a generic Gray count bit module is used to process the carry and count chain for each bit of the counter. Special consideration is given to the first and last bits of the counter to ensure correct termination and reset of the counter. A one bit gray code generic module is described such that a scalable counter can be generated recursively.

Abstract: The present invention is a counter that takes advantage of the speed and implementation of the LFSR counter by utilizing separate digit counters, each digit counter having a period that is a relative prime to the other digit counter periods. The total period will be the product of all the digit counter periods. Since all digits count independently, there is no carry structure between the digits and hence no delay incurred by carry chains. The pseudorandom number counting sequence for each digit still occurs but is ameliorated by the fact that the digital periods are small and can readily be converted to decimal equivalents by table-lookup and residue lookup.

Abstract: Method for realizing a binary counter that changes a partly permuted data word stored in a non-volatile memory and including a counter and a working memory and storing a data word in the form of memory words in the non-volatile memory. The method further comprises reading the memory words of the data word and storing the memory words in the working memory while performing an inverse reordering of k permutation bits of the data word, applying an inverse bijective mapping function to the k permutation bits of the data word, altering the data word, applying a bijective mapping function to the k permutation bits of the data word, performing a reordering of the k permutation bits, and checking each memory word for deviations from the memory word stored in the non-volatile memory and storing only those memory words in the non-volatile memory again for which this is the case.

Abstract: A saturating count counts received event signals up to a first predetermined number. An overflow counter counts overflows up to a second predetermined number. The counter indicates overflow when the overflow count is non-zero and saturates and stops counting at a maximum count when the overflow count reaches the second predetermined number. The counter can be read via a register read operation. The sum of the sum of the first predetermined number of bits and the second predetermined number of bits being an integral multiple of 8 bits.

Abstract: A processor architecture and instruction set is provided that is particularly well suited for cryptographic processing. A variety of techniques are employed to minimize the complexity of the design and to minimize the complexity of the interconnections within the device, thereby reducing the surface area required, and associated costs. A variety of techniques are also employed to ease the task of programming the processor for cryptographic processes, and to optimize the efficiency of instructions that are expected to be commonly used in the programming of such processes. In a preferred low-cost embodiment, a single-port random-access memory (RAM) is used for operand storage, few data busses and registers are used in the data-path, and the instruction set is optimized for parallel operations within instructions.

Abstract: The present invention provides a method and apparatus to check the arithmetic increment function through prediction of the change in the bit-level parity of the result by means of a series of identical cells connected in a linear array. The array predicts the change in parity produced by the arithmetic increment function which allows the increment function to be checked in an efficient manner. The advantages of the present invention are that the parity check design saves hardware cost over prior schemes that require duplication of incrementers and comparison of the results and schemes that require generation of parity after incrementing, and that the iterative, identical cell implementation of the parity predictor is well-suited for current VLSI and future digital logic circuits as they progress towards molecular, self-assembling components.

Abstract: A method and apparatus are used to generate FFT data addresses for a butterfly stage based upon a computation stage value. The method includes setting a selected bit of a binary word at a logical value, performing an addition operation by adding a logical “1” to the binary word, and skipping a carry bit as selected by a one-hot decoded stage value during the addition operation. The apparatus includes consecutive adders configured to store a binary value and perform an addition operation on the binary value, multiplexers configured to select either the carry out output of the current consecutive half adder or the carry out output of the previous consecutive half adder as the carry in input of a next consecutive adder, and sets of logic gates that provide one bit of the data address.

Abstract: An address generating circuit, in which address generation by a modulo addition is executed at high speed, is provided. The address generating circuit makes, a two input adder that adds an address and a renewing step, a three input adder and subtracter that adds the address and the renewing step and further adds the size of a modulo area to this added result or subtracts the size of the modulo area from this added result, and a selection judging circuit that generates a selection signal for selecting one of the outputs from the two input adder and the three input adder and subtracter, work in parallel and independently. And a multiplexer selects one of the outputted results from the two input adder and the three input adder and subtracter based on the selection signal from the selection judging circuit.

Abstract: An apparatus having two or more parallel carry chain structures, each of the carry chain structures comprising a series of logical structures, where at least one of the logical structures within each of the carry chain structures has an associated input node, output node and carry node. The input node corresponds to a function input term, the output node corresponds to an output term of the function and the carry node corresponds to a carry value to a following logical structure in the series of logical structures.

Abstract: The invention relates to a method for overload-free driving of an actuator, in which an activation counter is incremented or decremented each time an activation request signal occurs, in which, depending on each occurrence of an activation request signal, a drive signal for the actuator is generated if the counter reading of the activation counter is less than or greater than a predetermined maximum or minimum counter reading, in which the counter reading is in each case decremented or incremented if the time since the last generation of a drive signal or since the deactivation of the drive signal is greater than or equal to a predetermined or predeterminable interval time or if the time since the last decrementing of the activation counter is greater than or equal to the interval time.

Abstract: A command for incrementing a numeric value is inputted by pressing a “2” key. A command for decrementing the numeric value is inputted by depressing an “8” key. At least one of a process for incrementing the numeric value by the amount of increment according to the length of time during which the “2” key is held down and a process for decrementing the numeric value by the amount of decrement according to the length of time during which the “8” key is held down is performed to determine a value to be input.

Abstract: A method for a plus one operation includes dividing a binary number into bit sets including a least significant bit set, incrementing the least significant bit set, and, for each bit set other than the least significant bit set, incrementing the bit set unless any less significant bit sets comprises a zero. The bit sets are increment in one of two ways. If all bits of the bit set equal one, e.g., the bit set is 1111, then all bits of the bit set are simply complemented, sometimes called inverted, and set to zero. In all other instances, the least significant zero of the bit set is identified, and the least significant zero and all less significant bits, i.e., everything to the right of the least significant zero, is (are) complemented.

Abstract: Provided is an incrementing/decrementing apparatus that includes an adder having a first input and a second input, each of the first input and the second input comprising multiple bits. A first multi-bit signal is connected to the first input, and a second multi-bit signal is connected to the second input, the second multi-bit signal including multiple bits. The adder increments the first multi-bit signal by a quantity when an increment/decrement signal has a first value and decrements the first multi-bit signal by the quantity when the increment/decrement signal has a second value. The multiple bits of the second multi-bit signal include at least one bit based solely on a corresponding bit in the quantity and at least one bit based solely on a value of the increment/decrement signal.

Abstract: In a counter readout control apparatus comprising a plurality of counters, in which an upper-order counter performs a counting operation upon receiving a carry from a lower-order counter, this apparatus further comprising, a first means for resetting each flag storing memory in which a carry of each counter, with an exception of an uppermost-order counter, is stored (Step S21), a second means for sequentially reading out the plurality of counters from an upper-order counter to a lower-order counter (Step S22 to S25), a third means for, after reading each counter value by means of the second means, testing as to whether the carry is set or not in the flag storing memory (Step S26 to S29), and a fourth means for, in the case in which the carry is set in the flag storing memory, resetting the flag storing memory having the carry (Step S27A, S28A, S29A) and performing a re-read operation only of counters having an order higher than an order of a counter which has been changed due to a reception of the carry (Step

Abstract: A high speed incrementer/decrementer design is presented that computes the propagate, generate, and kill signals which are used to compute carries and sums from the incrementer inputs. By setting one input to “0” and the carry-in to “1”, the adder is used as an incrementer. In the design of the invention, a bit-wise decision is made whether to complement the input bit or not. The design also allows decrementing and supports both unsigned and 2's complement number representations.

Abstract: A computation circuit which can obtain n+m-digit accumulation results by using an n-digit computation unit. This computation circuit comprises a computation unit which performs additions of n-digit data; an m-digit up/down counter; and a control circuit which uses the up/down counter to generate the upper m digits of the computation result. In a preferred embodiment, the control circuit increments by one the up/down counter when carry-over occurs in the computation unit, and when the input data of the computation unit is negative, decrements by one the up/down counter. In another preferred embodiment, the control circuit increments or decrements by one the up/down counter when positive or negative overflow occurs in the computation unit, and decrements by one the up/down counter when the final computation result of the computation unit is negative or is a positive number greater than 2n−1−1.

Abstract: An incrementer pipelines the generation of carry lookahead signals. Count registers hold a current count of the incrementer. The current count is fed back as inputs to sum logic, which generates sum bits that are latched into the count registers as a next count. All-ones detect logic detects when all lesser-significance bits in the current count are ones. When all lesser bits are ones, the sum logic toggles the count bit to generate the sum bit for that bit position. Pre-carry logic generates pre-carry lookahead signals from the sum bits. The pre-carry lookahead signals are latched into pipelined carry registers. The pipelined carry registers drive pipelined carry lookahead signals to the all-ones detect logic. Thus carry lookahead signals are generated from a prior sum but used in a next clock cycle to generate then next sum.

Abstract: A four-rail incrementor/decrementor circuit is presented. The circuit is capable of operating in an asynchronous (i.e., lacking a clock signal) environment. The basic circuit can be cascaded to build incrementor/decrementors that can handle numbers of arbitrarily large size. The circuit can also achieve a 50% power savings over two-rail versions.

Abstract: An incrementer/decrementer architecture having a reduced internal block fanout which is achieved efficiently in terms of the silicon area needed to implement the incrementer/decrementer. The incrementer/decrementer of the present invention is characterized by a modified tree structure having operators located in such a manner that the maximum internal block fanout is equal to (incrementer/decrementer width)/8 for incrementer/decrementers having a width of at least 16 bits. For incrementer/decrementers having a width of less than 16 bits, the internal block fanout is 2. The routing complexity is increased in order to implement redundant overlapping operations which, in turn, decreases the internal block fanout. However, increases in routing complexity can be accomplished within the minimum X-by-Y area of each stage of the incrementer/decrementer. Therefore, the overall performance of the incrementer/decrementer of the present invention can be optimized while meeting minimum area requirements.

Abstract: Each binary carry logic circuit 20 of half adder circuits other than that for the least significant digit comprises a transfer gate 212 turned on when an input bit A2 is active and receiving a carry-in bit *C2 at its data input, and a transistor 23, turned on when the input bit A2 is inactive, connected between a power supply potential VDD and the data output of the transfer gate 212 a signal on which is a carry-out bit *C3. Transfer gates 212 to 214 of binary carry logic circuits other than that for the least significant digit are connected in chain, and are simultaneously on/off controlled by input bits A2 to A4, letting the carry-in bit *C2 from the least significant digit propagate through the transfer gate chain at a high speed.

Abstract: Disclosed is a novel n-bit binary counter with low power consumption, which comprises a set of half-adders for adding a “1” to an n-bit input signal, which includes a lower-order m bit component and a higher-order (n−m) bit component, and a set of D (data) flip-flops for storing outputs of the half-adders. The set of half-adders are divided into two sections, one of which is a first adder section for adding a “1” to the lower-order m bit component and the other of which is a second adder section for adding a carry signal from the first adder section to the higher-order (n−m) bit component. The set of D flip-flops are divided into two sections, one of which is a first register section to store outputs of the first adder section and the other of which is a second register section to store outputs of the second adder section. The n-bit input signal is comprised of the outputs of the first and second register sections.

Abstract: In an adder apparatus, a first logic circuit performs a NOR operation upon a first bit of an n-bit input signal and a control signal to generate a first signal. A second logic circuit performs an OR operation upon the first bit of the n-bit input signal and the control signal to generate a logic OR signal and performs a NAND operation upon the logic OR signal and a second bit of the n-bit input signal to generate a second signal. Each of third logic circuits performs a NAND operation upon an (i−1)th (i=3, 4, . . . , n) bit of the n-bit input signal and i-th bit of the n-bit input signal to generate a third signal. A carry signal generating circuit receives the first, second and third signals to generate “n” carry signals.

Abstract: The present invention is an incrementor that receives as inputs a 32-dit 1-of-4 operand and a 1-of-2 increment control signal. For each dit of the operand, the present invention determines whether the increment control signal, which is treated as a carry into the least significant dit, propagates into said dit. If so, the value of the dit is incremented. Otherwise, the dit value is output without modification. The present invention also generates a carry out signal if the increment control signal has propagated across all dits.

Abstract: A dynamic incrementer, implemented in the Self Resetting Complementary Metal Oxide Semiconductor (SRCMOS) circuit family, which internally performs single rail calculations and which generates the dual rail result using a strobing technique. The carry-lookahead function is implemented with an OR tree using the complement input signals, resulting in a very fast and economical incrementer.

Abstract: An incrementer pipelines the generation of carry lookahead signals. Count registers hold a current count of the incrementer. The current count is fed back as inputs to sum logic, which generates sum bits that are latched into the count registers as a next count. All-ones detect logic detects when all lesser-significance bits in the current count are ones. When all lesser bits are ones, the sum logic toggles the count bit to generate the sum bit for that bit position. Pre-carry logic generates pre-carry lookahead signals from the sum bits. The pre-carry lookahead signals are latched into pipelined carry registers. The pipelined carry registers drive pipelined carry lookahead signals to the all-ones detect logic. Thus carry lookahead signals are generated from a prior sum but used in a next clock cycle to generate then next sum.