Design of quadruple precision multiplier architectures with SIMD single and double precision support

Abstract

This paper proposes architectures for dual-mode and tri-mode dynamically configurable multiplier for quadruple precision arithmetic. The proposed dual-mode QPdDP multiplier architectures can either compute on a pair of quadruple precision (QP) operands or provide SIMD support for two-parallel (dual) sets of double precision (DP) operands. The proposed tri-mode QPdDPqSP multiplier architectures are aimed to include the four-parallel (quad) single precision (SP) along with dual-DP and a QP operand processing. For the underlying largest sub-component, the mantissa multiplier, two methods are analyzed to design the dual-mode/tri-mode architectures. One is based on the Karatsuba method, and in another a dual-mode/tri-mode Radix-4 Modified Booth (MB) multiplier is proposed. The proposed dual-mode/tri-mode MB multiplier requires few extra 2:1 MUXs as an overhead compared to a simple MB multiplier. To support dual-mode/tri-mode functioning other important sub-components of the FP multiplication are also re-designed for multi-mode support. The proposed architectures are synthesized using UMC 90 nm ASIC technology, and are compared against prior literature in terms of area, period, and a unified metric “Area (Gate Count) × Period (FO4) × Latency × Throughput (in cycles)”. The dual-mode/tri-mode FP architectures with MB mantissa multipliers shows better timings, however, those with Karatsuba mantissa multipliers acquires smaller area.