On 09/27/2012 01:39 PM, Rich Alderson wrote:
XKL's TOAD-1 is "an FPGA emulation", strictly speaking. It's
much more "grown up", though, than somebody spending a year working on
the VHDL or Verilog, then copping out and squirting it into a friggin'
eval board but never designing any hardware. ;)
Not, strictly speaking, true. The FPGAs + AMD 29xx sequencer in the XKL-1
CPU implement a microcode engine, and the extended PDP-10 architecture is
then implemented in microcode just as in the KL-10 and KS-10 processors.
The later XKL-2 processor, implemented in a single FPGA, is much closer
to what Ethan means, I would think, although still microcoded. The ucode
is part of the overall loadup of the FPGA from ROM at power-up.
Perhaps Ethan has in mind something more like what Neil Franklin attempted
a decade ago, or "dgcx" more recently.
That's a very blurry distinction, and is a path directly into
quicksand on this list. ;) Where DOES one draw the line between
hardware and firmware?
What I'd like to know about the XKL designs is: Who owns the design
files, and how can I get my hands on them? B-)
Dave McGuire, AK4HZ
New Kensington, PA