[Hardware] Fully unrolled RC5 on FPGA

[John L. Bass]

Mike Dini always makes the boards I drool over. I have an older board of his with
six Virtex 2000E's on it, (used to have two, before selling one). But this big bad
boy could probably come close to making a serious dent in DNet stats:

          http://www.dinigroup.com/index.php?product=DN9000k10PCI

from the press release:

          "The DN9000K10PCI will be supplied with 2 to 6 FPGAs in various sizes and speed
	ranges with prices start at only $12k. They are available “off-the-shelf” directly
	from The DINI Group and its agents."


loaded with LX330's, and augmented with heat sinks, a few dozen of these boards would
make DNet PC stats insigificant (at better than $25K/ea).

Now, back to what we can do. Checking retail pricing at AVNET, I see that the LX40's
are cheapest in FF668 packages, speed grade 10, at $386.10 if you buy more than 25
per order (speed grades 11 are $483, and 12 are $744). The slowest is frequently the
most cost effective.

LX25's in the same package are $244/ea with a 4wk lead time. It's unlikely that unrolling
a single stage will fit into the LX15's, because parts of the design do not scale ... such
as the E terms in the last stage.

Cost performance wise, using a parallel unrolled stage, it appears at first glance the
LX40 fully unrolled is more cost effective than the partially unrolled LX25 solution.
There would have to be an LX25 package cheaper than about $150 to make a difference,
which I don't see. Going up, LX80's would hold two fully unrolled engines, and are
a little over a grand. So the LX40 still appears the sweet spot in the pricing.

If ordering more than a $1M/yr, you can get special Xilinx pricing which might reduce
the device costs by about half for mid sized and larger devices.

John