Re: [oc] Ethernet Mac

[Victor the Cleaner <jonathan@canuck.com>]

On Thu, Mar 30, 2000 at 06:22:42PM -0500, Graham Seaman wrote:
> > Uh, "what?"  The above is semi-accurate and suggests you don't 
> > understand these toolchains.  
> I think there are some cross-purposes here: one of you is talking about
> commercial EDA software which runs on Unix, the other about free (as in gpl)
> EDA software... 
 
[stuff snipped]
 
> >  Alliance isn't a compiler - it's 
> > the back-end place-and-route (PAR), bitstream generator, and other
> > device-specific tools for supporting their parts STARTING with the
> > netlist.  
> I believe this is at cross-purposes: there is the Xilinx Alliance 
> you're talking about, and Alliance the gpl-ed software which has a
> back-end which handles both MOSIS and old Xilinx devices. The frontend
> compiles a very limited subset of VHDL (this
> may be very out-of-date information; the current version of the
> free Alliance is at: http://www-asim.lip6.fr/alliance/ ).
> 
> I don't believe any of the free (gpl-ed) systems avoid the need
> for the commercial place-and-route, bit-stream generation software
> for any recent FPGAs. 

Oh, *man*.  I didn't know of the existence of another package named
"Alliance".  I can't imagine anyone being so stupid as to name a piece
of GPLed software the same as a commercial package already in the same
field.  There's *got* to be a connection.  Perhaps someone will fill
in the blanks.

To the best of my knowledge, you're right on your last point - that
the vendor-specific PAR, bitstream generation, etc. is extremely 
unlikely to ever come from anyone but that vendor.  In the Real World
(read: where the people who spend the most money for this stuff - the
ciscos and nortels et.al.) designers remain very concerned about the
security of their designs and IP.  Specifically, they're very, very
nervous about the possibility that someone might reverse-engineer the
bitstream that they ship in their products.  Xilinx is emphatic about
the difficulty of reverse-engineering the bitstream (they claim it's
all but impossible), and it would severely compromise that position 
with their biggest customers if they released the bitstream generation 
algorithm.

So, like it or not, if you want to design with these parts you're going
to have to use one or another of their back-end packages.  Period.

Jonathan