37 results about "Carry propagation" patented technology

Quotient digit selection logic using a three-bit carry propagate adder is presented. An enhanced quotient digit selection function prevents the working partial remainder from becoming negative if the result is exact. The enhanced quotient digit selection logic chooses a quotient digit of zero instead of a quotient digit of one when the actual partial remainder is zero. Using a four bit estimated partial remainder where the upper four bits are zero, a possible carry propagation into fourth most significant bit is detected. This can be accomplished by looking at the fourth most significant sum and carry bits of the redundant partial remainder. If they are both zero, then a carry propagation out of that bit position into the least significant position of the estimated partial remainder is not possible, and a quotient digit of zero is chosen. This provides a one cycle savings since negative partial remainders no longer need to be restored before calculating the sticky bit. Extra hardware is eliminated because it is no longer necessary to provide any extra mechanism for restoring the preliminary final partial remainder. Latency is improved because no additional cycle time is required to restore negative preliminary partial remainders. In an alternative embodiment, where the upper three bits of the estimated partial remainder are ones while the fourth most significant bit is zero, a quotient digit of negative one is chosen. This alternative embodiment allows correct exact results in all rounding modes including rounding toward plus or minus infinity.

An arithmetic unit, for example a multiply and accumulate (MAC) unit 42, for a processing engine includes a partial product reduction tree 480. The partial product reduction tree will generate carry results and provides a final output to a final adder 470 connected to the partial production reduction tree. Unbiased rounding logic 476 is provided. A carry propagation tree is responsive to the carry results for anticipating a zero on each of N least significant bits of the final adder. When zero is anticipated on each of N least significant bits of the final adder, the carry propagation tree is operable to generate an output signal 477 which is used by the unbiased rounding stage to force the (N+1)th least significant bit of the final adder to zero. Through the use of a carry propagation tree to predict, or anticipate zeros on the N least significant bits, unbiased rounding can be effected without a time penalty in that a carry propagation tree can be configured to be at least a rapid as the carry propagation of the final adder. Where a zero anticipation function is provided, this can also be mapped onto the carry propagation tree, thus providing an efficient hardware implementation through sharing of that hardware between functions.

Certain example embodiments relate to selective change propagation techniques for supporting partial roundtrips in model-to-model transformations. In certain example embodiments, enablement checking is performed to determine whether a propagation operation can be performed for an object. If the object passes enablement checking, the propagation is executed by, for example, creating the object(s) in a business-oriented (e.g., EPC) model; updating relevant internal attributes of technical (e.g., BPMN) objects that allow for the successful merge; optionally correcting user-introduced errors in the technical model; and properly connecting the pulled-up objects with their surroundings. The connecting is performed so that the objects advantageously appear as if the current business-oriented model was used for the merge. According to certain example embodiments, the connecting may be deterministic, e.g., such that the result will be the same regardless of order or sequence in which the propagations are made.

A method of reducing power consumption and/or enhancing computation speed in the modulus multiplication operation of a Montgomery modulus multiplication module. A coding scheme reduces the need for an adder or memory element for obtaining multiple modulus values, and the use of carry save addition with carry propagation addition enhances the computational speed of the multiplication module.

Embodiments disclosed herein include vector processing carry-save accumulators employing redundant carry-save format to reduce carry propagation. The multi-mode vector processing carry-save accumulators employing redundant carry-save format can be provided in a vector processing engine (VPE) to perform vector accumulation operations. Related vector processors, systems, and methods are also disclosed. The accumulator blocks are configured as carry-save accumulator structures. The accumulator blocks are configured to accumulate in redundant carry-save format so that carrys and saves are accumulated and saved without the need to provide a carry propagation path and a carry propagation add operation during each step of accumulation. A carry propagate adder is only required to propagate the accumulated carry once at the end of the accumulation. In this manner, power consumption and gate delay associated with performing a carry propagation add operation during each step of accumulation in the accumulator blocks is reduced or eliminated.

A method for transparently presenting different size operands to be processed is provided. The method initiates with providing a first operand having a first bit-width. Then, a bit width of a second operand associated with a processor is determined. The second operand has a greater bit width than the first operand. Next, the first operand is transformed by aligning a least significant bit of the first operand to a lowest bit position of a transformed operand having a bit size equal to the second operand. Then, the bits of the transformed operand are sign extended and padded in a manner to allow carry propagation. Next, the transformed operand is transmitted to the processor. A method for shifting operands and a processor are also provided.

A radix-2k Montgomery multiplier including an input coefficient generation unit to receive a multiplier, a multiplicand, a modulus, a sum and a previous sum, to generate and to output a partial product and a multiple modulus by using at least one of the multiplier, the multiplicand, the modulus and the sum, and to divide and to output the received previous sum into units of k bits, an accumulator circuit to receive the partial product, the multiple modulus and k bits of the previous sum from the input coefficient generation unit, and to generate and to output a carry and a sum by summing the partial product, the multiple modulus and the previous sum, and a carry propagation adder (CPA) circuit to generate and to output an ultimate sum by using the carry and the sum.

A multiplier circuit is disclosed including a Wallace tree block and a carry propagation adder. The Wallace tree block includes a sum calculation block adding partial products for each digit and a carry calculation block adding carries obtained in the addition by the sum calculation block. In the case of multiplication over an extension field (finite field GF(2ⁿ)) of two, a result of calculation by the sum calculation block is outputted. The carry propagation adder adds the result of calculation by the sum calculation block and a result of calculation by the carry calculation block. In the case of multiplication for integers (finite field GF(p)), a result of calculation by the carry propagation adder is outputted.

The present invention relates to a carry look-ahead adder. The carry look-ahead adder is configured in 4-bit units in general. Each 4-bt carry look-ahead adder is combined with a carry look-ahead generating unit to constitute a carry look-ahead adder that can process input signals of larger size. The carry look-ahead adder according to the embodiment of the present invention calculates carry of each bit sequentially not by using any carry generation function or any carry propagation function but by using previous bit when generating an internal carry in the adder, so that propagation delay is allowed a little but the logic gate circuit can be simplified.

An apparatus and method that perform partitionable carry-lookahead logic on two N-nary operands. The operands may be selectably partitioned into 8-bit, 16-bit, 32-bit, or 64-bit operands. The present invention performs carry-lookahead logic to calculate a block carry-lookahead indicator for a grouping, or block, of bits. The present invention forces the block indicator to a "Halt" value if the block comprises the most significant block within a partition, thus interrupting the carry propagation chain on partition boundaries. The present invention supports interruption of the carry propagation chain for both addition and subtraction.

The invention provides an approximate multiplier based on approximate 6-2 and 4-2 compressors and a calculation method. The approximate multiplier comprises a partial product generation module, a partial product tree-shaped compression module and a carry adder module. The partial product generation module is an AND gate array, and each bit of a multiplier and a multiplicand is subjected to AND operation to obtain a corresponding partial product; the partial product tree compression module comprises an accurate compression unit, an approximate compression unit and a truncation unit; and the carry propagation adder is used for combining an output signal obtained by adding output signals of the precise compression unit and the approximate compression unit with an output signal of the truncation unit to obtain a result. According to the invention, the area cost, time delay and power consumption of the multiplier can be greatly reduced, so that the performance of the multiplier is improvedand the energy consumption is reduced.

A parallel self-timed adder (PASTA) is disclosed. It is based on recursive formulation and uses only half adders for performing multi-bit binary addition. Theoretically the operation is parallel for those bits that do not need any carry chain propagation. Thus the new approach attains logarithmic performance without any special speed-up circuitry or look-ahead schema. The corresponding CMOS implementation of the design along with completion detection unit is also presented. The design is regular and does not have any practical limitations of fan-ins or fan-outs or complex interconnections. Thus it is more suitable for adoption in fast adder implementation in high-performance processors. The performance of the implementation is tested using SPICE circuit simulation tool by linear technology. Simulation results show its superiority over cascaded circuit adders. A constant time carry propagation is also achieved using the proposed implementation by tuning the CMOS parameters.

A method for an associative memory device includes replacing a set of three multi-bit binary numbers P, Q and R, stored in the associative memory device, with two multi-bit binary numbers X and Y, also stored in the associative memory device, wherein a sum of the binary numbers P, Q and R is equal to a sum of the binary numbers X and Y. A system includes an associative memory array having rows and columns and a multi-bit multiplier. Each column of the array stores two multi-bit binary numbers to be multiplied. The multi-bit multiplier multiplies, in parallel, the two multi-bit binary numbers per column by concurrently processing all bits of partial products generated by the multiplier. The multiplier performs the processing without any carry propagation delay when adding all but the last two partial products.

Floating point Multiply-Add, Accumulate Unit, supporting BF16 format for Multiply-Accumulate operations, and FP32 Single-Precision Addition complying with the IEEE 754 Standard. The Multiply-Accumulate unit uses higher radix and longer internal 2's complement significand representation to facilitate precision as well as comparison and operation with negative numbers. The addition can be performed using Carry-Save format to avoid long carry propagation and speed up the operation. The circuit uses early exponent comparison to shorten the accumulate pipeline stage. Operations including overflow detection, zero detection and sign extension are adopted for 2s complement and Carry-Save format.

The invention discloses a fast algorithm for calculating the undercurrent path of an adder based on a memristor array, comprising the following steps: 1) carrying subsurface current path mapping, calculating the states of RG, RD and RP in advance, and determining the carrying calculation paths of different bits; 2) constructing a serial carry chain, and as a transmission path cannot be formed by the array structure, a carry propagation path control by the RP needs to be customized to cope with the RP in step 1); 3) after that carry calculation of the summation calculation bits is completed, completing the summation calculation of all the bits in parallel through the corresponding logic. The invention is based on the design of the adder of the memristor memory array, and utilizes HSPICE anda novel non-volatile memory simulation tool NVSim to test the design, so as to remarkably improve the computational performance, the area overhead and the power consumption overhead.