167 MHz radix-4 floating point multiplier

Abstract

An IEEE floating point multiplier with partial support for subnormal operands and results is presented. Radix-4 or modified Booth encoding and a binary tree of 4:2 compressors are used to generate the 53/spl times/53 double-precision product. Delay matching techniques were used in the binary tree stage and in the final addition stage to reduce cycle time. New techniques in rounding and sticky-bit generation were also used to reduce area and timing. The overall multiplier has a latency of 3 cycles a throughput of 1 cycle, and a cycle time of 6.0 ns. This multiplier has been implemented in a 0.5 /spl mu/m static CMOS technology in the UltraSPARC RISC microprocessor.<>