FPGA-Specific Arithmetic Optimizations of Short-Latency Adders

Hong Diep Nguyen (1) , Bogdan Pasca (1) , Thomas B. Preusser (2)

1 ARENAIRE - Computer arithmetic
2 TUD - Institute of Computer Engineering

Integer addition is a pervasive operation in FPGA designs. The need for fast wide adders grows with the demand for large precisions as, for example, required for the implementation of IEEE-754 quadruple precision and eliptic-curve cryptography. The FPGA realization of fast and compact binary adders relies on hardware carry chains. These provide a natural implementation environment for the ripple-carry addition (RCA) scheme. As its latency grows linearly with the operand width, wide additions call for acceleration, which is quite reasonably achieved by addition schemes built from parallel RCA blocks. This study presents FPGA-specific arithmetic optimizations for the mapping of carry-select/increment adders targeting the hardware carry chains of modern FPGAs. Different trade-offs between latency and area are presented. The proposed architectures represent attractive alternatives to deeply pipelined RCA schemes.

Mots clés: FPGA; Addition; Carry-chain; Carry-select; Carry-increment

Domaines: Arithmétique des ordinateurs

Hong Diep Nguyen, Bogdan Pasca, Thomas B. Preusser. FPGA-Specific Arithmetic Optimizations of Short-Latency Adders. 2011 International Conference on Field Programmable Logic and Applications (FPL), Sep 2011, Chania, Greece. pp.232 - 237, ⟨10.1109/FPL.2011.49⟩. ⟨ensl-00542389⟩