Create a VAX CPU with FPGA?

Curt @ Atari Museum curt at
Fri Mar 4 18:01:38 CST 2005

I still think, a PC with simh and a PCI to Qbus adapter to allow the use 
of Qbus peripherals that is more at hobbyist cost levels is a far better 
solution, I wish the companies current selling those $2,500-$3,000 cards 
would reduce their costs to more in line with a $500 range, I 'm sure a 
lot of us would buy cards and they'd make it up in quantity of sales.


Paul Koning wrote:

>>>>>>"9000" == 9000 VAX <vax9000 at> writes:
> 9000> There are many "soft CPUs" around. I wonder how hard it is to
> 9000> create a soft VAX CPU core that can be load into an FPGA. Other
> 9000> than to design from scratch, I think it might be easier if we
> 9000> grab the VAX-11/780, 750, or 730 schematics, and throw them
> 9000> into an FPGA compiler. The 780 was implemented with TTL, the
> 9000> 750 with gate array, and 730 with AMD 2901. I think the 730
> 9000> scheme might be the easiest to implement with an FPGA.
>You'd also need the microcode.  The schematics will only give you the
>micro-engine.  The microcode is what turns that into a VAX.
>I suppose you could do a VAX in hardwired logic, but that would be
>HARD given the instruction set.  A bit easier if you use the minimum
>subset, I suppose.
>	paul

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