Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!apple!vsi1!wyse!adyer From: adyer@milo.wyse.com (Andrew Dyer x2446) Newsgroups: comp.lang.forth Subject: Re: FPGA Forth engines Message-ID: Date: 13 Dec 90 17:20:37 GMT References: <9012061501.AA20109@ucbvax.Berkeley.EDU> <1990Dec6.223103.5766@cbnewse.att.com> <1990Dec7.143245.29515@aplcen.apl.jhu.edu> <1990Dec11.181204.10500@aplcen.apl.jhu.edu> Sender: news@wyse.wyse.com Distribution: na Organization: Wyse Technology, Inc. Lines: 35 In-reply-to: mef@aplcen.apl.jhu.edu's message of 11 Dec 90 18:12:04 GMT In article <1990Dec11.181204.10500@aplcen.apl.jhu.edu> mef@aplcen.apl.jhu.edu (Marty Fraeman) writes: (mucho stuff deleted) the stacks off the FPGA and put them in static ram like the Novix chip did then you take a big speed hit. For proof look at the top speed of the Novix vs the RTX2000. I am not framiliar with the Novix implementation, but I would think that some of the cache RAMs available today could be used for this function. >at toggle rates of 70 MHz.(Xilinx and AMD) I wouldn't trust I/O rates >to be more than 50 Mhz tho. Assuming a 50 MHz clock, and 6 clock >cycles/instruction you get 8.33 MHz cycle rate. Not too shabby. > Yes, for one flip flop maybe, but what happens when you finish routing a real circuit? As long as every thing is synchronous things shouldn't be too bad. We have done a couple tests of these FPGAs at close to 50MHz. Routing was important, and so was on/off chip delay, but after mucking about some we got them to simulate o.k. Admittedly it was never made, but I believe their simulator was reasonably accurate. (small edit here) Perhaps he (Phil Koop) could comment on performance of the discrete vs integrated implementation. I wouldn't expect a discrete to be able to do more than 75% of what the integrated version would, but I was thinking of ``public domain'' hardware and not a release of a commercial product. -- {uunet, mips, decwrl}!wyse!adyer or adyer@wyse.com " I think I woke up on the wrong side of the food chain today..."