27 Apr
2016
27 Apr
'16
7:34 p.m.
On Wed, Apr 27, 2016 at 7:09 PM, Jon Elson <elson at 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.