AMD bit-slice machines
shoppa_classiccmp at trailing-edge.com
Sat Dec 31 10:45:13 CST 2005
Jan-Benedict Glaw <jbglaw at lug-owl.de> wrote:
> > The am2901 is just a chip. The smarts are in the microcode ;-)
> Is there some really interesting documentation available for these
> chips and maybe some microcode for some really simple task? I'd like
> to really understand how bit-slice CPUs do work to form something like
> a VAX CPU.
At the application-specific level, the classic reference
is "Mick and Brick". I think there's a PDF floating around on the web
but I don't know exactly where.
Bitsavers has lots of AMD2901 stuff including an app note showing
how to build a faster 8080A out of 'em, with some comments about tradeoffs
The KS10 microcode is on the web, as well as some drawings, but it's
not nearly as accessible as a simple micro like the 8080A.
VAXen are necessarily much more complicated, although the tradeoffs
as to circuitry vs microcode vs instruction emulation will be common to
any microcoded implementation. Bob Supnik has some non-2901-specific
comments and important personal narrative on his VAX and PDP-11 designs at
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