For years, ARC International has considered adding an optional floating-point unit (FPU) to its 32-bit customizable processor cores, but it has always been deterred by the cost of the additional logic gates and power. A fully equipped FPU with its own pipeline and register file could double or triple the silicon area of a small embedded RISC processor. At last week's Spring Processor Forum, ARC unveiled FPX-Floating-Point extensions-which significantly improve on the performance of a software-emulation library while requiring fewer gates than a complete FPU. ARC's solution is remarkably similar to the optional floating-point extensions for MicroBlaze v4.00 that Xilinx announced at the same session of SPF. One important difference is that ARC's extensions support both single- and double-precision operations, whereas the Xilinx extensions are limited to single-precision operations. (See MPR 5/17/05-02, "MicroBlaze Can Float.")
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