A New Architecture For Multiple-Precision Floating-Point Multiply-Add Fused Unit Design

The floating-point multiply-add fused (MAF) unit sets a new trend in the processor design to speed up floatingpoint performance in scientific and multimedia applications. This paper proposes a new architecture for the MAF unit that supports multiple IEEE precisions multiply-add operation (AtimesB+C) with Single Instruction Multiple Data (SIMD) feature. The proposed MAF unit can perform either one double-precision or two parallel single-precision operations using about 18% more hardware than a conventional double-precision MAF unit and with 9% increase in delay. To accommodate the simultaneous computation of two single-precision MAF operations, several basic modules of double-precision MAF unit are redesigned. They are either segmented by precision mode dependent multiplexers or attached by the duplicated hardware. The proposed MAF unit can be fully pipelined and the experimental results show that it is suitable for processors with floatingpoint unit (FPU).