Han Carlson Adder(Professor Han invented Han Carlson adder in part of his Ph. D. dissertation). currently widely used in Intel Pentium Micro. Download scientific diagram | (a) Han-Carlson (HC) adder; from publication: Power-aware Design of Logarithmic Prefix Adders in Sub-threshold Regime: A. Key Words – Parallel Prefix Adders, Han-Carlson Adder, area, prefix computation, Power Consumption, delay. 1. Introduction. VLSI binary adders are critically.

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Hybrid Han-Carlson adder – Semantic Scholar

AMG provides constant-coefficient multipliers in the form: Therefore, let Gi and Pi denote the generation and propagation at the ith stage, we have: Dadda tree is based on 3,2 counters.

Figure 18 shows an operand overturned-stairs tree, where CSA indicates a carry-save adder having three multi-bit inputs and two multi-bit outputs. A ripple-block carry look-ahead adder RCLA consists of N m-bit blocks arranged in such a way that carries within blocks are generated by carry look-ahead but carries between blocks are rippled. Unlike the conditional-sum adder, the sizes arder the kth group is chosen so as to equalize the delay of the ripple-carry within the group and the delay of the carry-select chain from group 1 to group k.

Hardware algorithms for arithmetic modules

AMG provides multiply accumulators in the form: Array is a straightforward way to accumulate partial products using a number of adders. Figure 22 shows a n-term multiply accumulator. We employ Dadda’s strategy for constructing 7,3 counter trees. Figure 3 addef the parallel prefix graph of a bit BCLA, where the symbol solid circle indicates an extension of the fundamental carry operator described at Parallel prefix adders.


Table 1 shows hardware algorithms that can be selected for multi-operand adders in AMG, where the bit-level optimized design indicates that the matrix of partial product bits is reorganized to optimize the number of basic components.

Hardware algorithms for arithmetic modules

Figure 16 shows an operand Wallace tree, where CSA indicates a carry-save adder having three multi-bit inputs and two multi-bit outputs. This adder has a hybrid design combining stages from the Brent-Kung and Kogge-Stone adder.

Each set includes k sum bits and an outgoing carry. The PPA stage then performs multi-operand addition for all the generated partial products and haj their sum in carry-save form.

The equation can be interpreted as stating that there is a carry either if one is generated at that stage or if one is propagated from the preceding stage. In the following, we briefly describe the hardware algorithms that can be handled by AMG.

You can further increase the number of product terms computed in a single cycle depending on your target applications. Another way to design a practical carry look-ahead adder is to reverse the basic design principle of the RCLA, that is, to ripple carlzon within blocks but to generate carries between blocks by look-ahead.

Figure 6 is the parallel prefix graph of a Kogge-Stone adder.

Figure 8 is the parallel prefix graph of a Han-Carlson adder. This optimal organization of block size includes L blocks with sizes k1, k2, The most straightforward implementation of a final stage adder for two n-bit operands is a ripple carry adder, which requires n full adders FAs.

In this generator, we employ a minimum length encoding based on positive-negative representation.

The Booth recoding of the multiplier reduces the number of partial products and hence has a possibility of reducing the amount of hardware involved and the execution time. Partial products are generated with Radix-4 modified Booth recoding. The number of wiring tracks is a measure of wiring complexity.


Hybrid Han-Carlson adder

Generalized MAC Figure Arithmetic Module Generator AMG supports adcer hardware algorithms for two-operand adders and multi-operand adders. Wallace tree is known for their optimal computation time, when adding multiple operands to two outputs using carry-save adders. The hardware algorithms for constant-coefficient multiplication are based on multi-input 1-output addition algorithms i.

The basic idea in hab conditional sum adder is to generate two sets of outputs for a given group of operand bits, say, k bits. In this generator, the group lengths follow the simple arithmetic progression 1, 1, 2, 3, Overturned-stairs tree requires smaller number of wiring tracks compared with the Wallace tree and has lower overall delay compared with the balanced delay tree.

The main idea behind carry look-ahead addition is an attempt to generate all incoming carries in parallel and avoid waiting until the correct carry propagates from the stage FA of the adder where hhan has hn generated.

To reduce the hardware complexity, we allow the use of 6,35,34,33,2and 2,2 counters in addition to 7,3 counters. Redundant binary RB addition tree has a more regular structure than an ordinary CSA tree made of 3,2 counters because the RB partial products are added up in the binary tree form by RB adders.