The floating-point unit of the PowerPC 603e microprocessor

The IBM PowerPC 603e(TM) floating-point unit (FPU) is an on-chip functional unit to support IEEE 754 standard single- and double-precision binary floating-point arithmetic operations. The design objectives are to be a low-cost, low-power, high-performance engine in a single-chip superscalar microprocessor. Using less than 15 mm(2) of the available silicon area on the chip (the size of the PowerPC 603e microprocessor is 98 mm(2)) and operating at the peak clock frequency of 100 MHz, an average single-pumping multiply-add-fuse instruction has one-cycle throughput and four-cycle latency. An average double-pumping multiply-add-fuse instruction has two-cycle throughput and five-cycle latency. The estimated performance at 100 MHz is 105 against the SPECfp92(TM) benchmark.