Carry Select Adder (CSLA) is one of the fastest adder used in many data processing processors to perform fast arithmetic functions. The structure of the CSLA suggests that there is scope for reducing the area in the CSLA. This work presents a simple and efficient gate level modification to significantly reduce the area of the CSLA. This method uses first, the implementation of the adder and then the excess of an adder. Based on this modified 128-bit square root CSLA (SQRT CSLA) architecture has presented and compared with the regular CSQ SQRT architecture. For the modified and regular SQRT and CSLA adders, the theoretical calculations for the delay and area are tabulated. Experimental delays and area comparisons are performed for both the regular SQRT and the modified SQRT.
Carry Select Adder (CSLA) provides one of the fastest features. Traditional CSLA requires large area and more energy. Recently a new CSLA adder has been proposed that performs quick addition, maintaining a low energy consumption and less area. This work focuses mainly on the implementation of 128-bit low-power area and efficient lead selecter using 0.18 μm of CMOS technology. Based on the efficient modification of the door level, the CSLA architecture of 128-b Square Scheme Block (SSB) has been developed and compared with the regular CSLA CSLA architecture. The performance of the proposed CSLA SSB is manually evaluated in terms of delay, power and area manually with logical effort and also through custom design. The proposed design has been developed using verilog HDL and synthesized cadence in RTL compiling using TSMC's typical library of 0.18μm technology.
Additives are one of the most critical arithmetic circuits in a system and their performance affects the overall performance of the system. Carry Select Adder (CSLA) is one of the fastest adder used in many data processing processors to perform fast arithmetic functions. From the structure of the CSLA, it is clear that there is room to reduce the area and the energy consumption in the CSLA. In this paper, an efficient area transport selection adder was proposed by sharing the common Boolean logical term. After the logical optimization and the partial circuit compartment, we only need an XOR gate and an inverter gate for summing. Through the multiplexer, we can select the final sum only and to carry the selection we need only one AND gate and one OR gate. Based on this modification, the CSLA architecture of 16, 32, 64 and 128 bits has been developed and compared with the conventional CSLA architecture. The proposed design considerably reduces the area compared to other CSLAs. From this improvement, the gate count of a 128-bit transfer adder can be reduced from 3320 to 1664. The proposed structure is implemented in Artix-7 FPGA. Compared to the proposed design, the conventional CSLA has a 65.80% less area.