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T. Lynch, E.E. Swartzlander, Jr., "A Spanning Tree Carry Lookahead Adder," IEEE Transactions on Computers, vol. 41, no. 8, pp. 931939, August, 1992.  
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@article{ 10.1109/12.156535, author = {T. Lynch and E.E. Swartzlander, Jr.}, title = {A Spanning Tree Carry Lookahead Adder}, journal ={IEEE Transactions on Computers}, volume = {41}, number = {8}, issn = {00189340}, year = {1992}, pages = {931939}, doi = {http://doi.ieeecomputersociety.org/10.1109/12.156535}, publisher = {IEEE Computer Society}, address = {Los Alamitos, CA, USA}, }  
RefWorks Procite/RefMan/Endnote  x  
TY  JOUR JO  IEEE Transactions on Computers TI  A Spanning Tree Carry Lookahead Adder IS  8 SN  00189340 SP931 EP939 EPD  931939 A1  T. Lynch, A1  E.E. Swartzlander, Jr., PY  1992 KW  spanning tree carry lookahead adder; significant adder; Advanced Micro Devices; Am29050 microprocessor; hybrid carry lookaheadcarry select; carry lookahead tree; CMOS; load distribution; layout; 56 bit; adders; carry logic; CMOS integrated circuits; integrated logic circuits; trees (mathematics). VL  41 JA  IEEE Transactions on Computers ER   
The design of the 56b significant adder used in the Advanced Micro Devices Am29050 microprocessor is described. Originally implemented in a 1 mu m design role CMOS process, it evaluates 56b sums in well under 4 ns. The adder employs a novel method for combining carries which does not require the back propagation associated with carry lookahead, and is not limited to radix2 trees, as is the binary lookahead carry tree of R.P. Brent and H.T. Kung (1982). The adder also utilizes a hybrid carry lookaheadcarry select structure which reduces the number of carriers that need to be derived in the carry lookahead tree. This approach produces a circuit well suited for CMOS implementation because of its balanced load distribution and regular layout.
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