Configurable circuits include an input selection region, a computation region, a switching region, and an output region. The input selection region includes a set of input multiplexers and selects and routes input signals. The computation region includes a set of lookup tables, each lookup table being coupled to selected signals from the input selection stage to generate a respective output signal. The switching region includes a set of output multiplexers, each output multiplexer being coupled to output signals from the set of lookup tables to provide circuit outputs responsive to respective output selection signals. The output region includes a domino logic stage, having a set of transistors, coupled to output signals from the set of lookup tables to provide circuit outputs that determine combinations of the signals output by the set of lookup tables.

A system includes a non-destructive associative memory array and a predictor, a selector and a summer. The memory array includes a plurality of sections, each section includes cells arranged in rows and columns, to store bit j from a first multi-bit number and bit j from a second multi-bit number in a same column in section j. The predictor generally concurrently predicts a plurality of carry out values in each of the sections and the selector selects one of the predicted carry out values for all bits. The summer generally concurrently, for all bits, calculates a sum of the multi-bit numbers using the selected carry-out values.

A system includes a non-destructive associative memory array and a predictor, a selector and a summer. The memory array includes a plurality of sections, each section includes cells arranged in rows and columns, to store bit j from a first multi-bit number and bit j from a second multi-bit number in a same column in section j. The predictor generally concurrently predicts a plurality of carry out values in each of the sections and the selector selects one of the predicted carry out values for all bits. The summer generally concurrently, for all bits, calculates a sum of the multi-bit numbers using the selected carry-out values.

A Vector Checksum instruction. Elements from a second operand are added together one-by-one to obtain a first result. The adding includes performing one or more end around carry add operations. The first result is placed in an element of a first operand of the instruction. After each addition of an element, a carry out of a chosen position of the sum, if any, is added to a selected position in an element of the first operand.

A Vector Checksum instruction. Elements from a second operand are added together one-by-one to obtain a first result. The adding includes performing one or more end around carry add operations. The first result is placed in an element of a first operand of the instruction. After each addition of an element, a carry out of a chosen position of the sum, if any, is added to a selected position in an element of the first operand.

A Vector Checksum instruction. Elements from a second operand are added together one-by-one to obtain a first result. The adding includes performing one or more end around carry add operations. The first result is placed in an element of a first operand of the instruction. After each addition of an element, a carry out of a chosen position of the sum, if any, is added to a selected position in an element of the first operand.

A Vector Checksum instruction. Elements from a second operand are added together one-by-one to obtain a first result. The adding includes performing one or more end around carry add operations. The first result is placed in an element of a first operand of the instruction. After each addition of an element, a carry out of a chosen position of the sum, if any, is added to a selected position in an element of the first operand.

Addition circuitry performs a saturating addition of a first number and a second number to generate a result value indicating an addition result corresponding to addition of the first number and the second number when the addition result is within a predetermined range and indicating a saturation value when the addition result is outside the predetermined range. The addition circuitry comprises: saturation lookahead circuitry to determine, for each lane of the result value, a respective set of one or more saturation lookahead status indications indicative of whether that lane should be set to represent part of the saturation value; and addition result generating circuitry to generate result bits for each lane, with a given lane of the result value having a value determined as a function of corresponding bits of the first and second numbers and a corresponding set of one or more saturation lookahead status indications determined for that lane by the saturation lookahead circuitry.

Addition circuitry performs a saturating addition of a first number and a second number to generate a result value indicating an addition result corresponding to addition of the first number and the second number when the addition result is within a predetermined range and indicating a saturation value when the addition result is outside the predetermined range. The addition circuitry comprises: saturation lookahead circuitry to determine, for each lane of the result value, a respective set of one or more saturation lookahead status indications indicative of whether that lane should be set to represent part of the saturation value; and addition result generating circuitry to generate result bits for each lane, with a given lane of the result value having a value determined as a function of corresponding bits of the first and second numbers and a corresponding set of one or more saturation lookahead status indications determined for that lane by the saturation lookahead circuitry.

Embodiments described herein are directed to mixed-radix carry-lookahead adders and methods performed thereby. The mixed-radix carry-lookahead adder includes an multiple carry-lookahead stages, where each stage may be of a different radix. Each stage operates on input bits, creating and implementing propagate and generate signals for each bit. The carry-lookahead stages also compute an XOR of the inputs that is forwarded to a final carry-lookahead stage. The elements of the initial and subsequent carry-lookahead stages are arranged such that each of the propagate and generate output signals passes through a minimal number of passive transmission lines. The final stage of the mixed-radix carry-lookahead adder includes an XOR logic gate configured to receive the generate output from an intermediate carry-lookahead stage and XOR the generate output received from the intermediate carry-lookahead stage with the computed XOR signal forwarded from the initial carry-lookahead stage to produce a sum of the input bits.