On Wed, Apr 27, 2016 at 7:09 PM, Jon Elson <el...@pico-systems.com> wrote: > Sure. A VAX 11/780 had a 5 MHz clock! Would be hard for an emulator to NOT > beat that! Later models did run faster, but not vastly faster, due to the > technology of the time.
I'm not sure what would qualify as "vastly faster", but I take it that 170.9 MHz doesn't? (also required fewer clocks per instruction than the 11/780) A well-tuned VAX design in a recent FPGA family (Xilinx 7-series or newer, or Altera Stratix V or newer) might be able to outperform the fastest "real" VAX, but perhaps not by a whole lot. FPGAs are generally much more efficient at implementing RISC processors, but it's difficult to get a whole lot more than 200 MHz for the cost-optimized FPGAs, or 350 MHz for the (expensive) performance-optimized FPGAs. I've designed VHDL cores equivalent to microprocessors such as the RCA 1802, National Semiconductor PACE, and DEC/Western Digital LSI-11 (at the microarchitecture level). I'd like to tackle something more sophisticated, but it's hard to find enough time.
