26 Aug
1999
26 Aug
'99
11:47 a.m.
Making a processor is not hard (although FPGAs might
make it harder than
just using simple TTL chips -- some of the manufacturer's claims on this
are plain false). I'd not try to re-implement the PDP11 unless you had a
good reason to do that -- rather, design an instruction set and
architecture and implement it.
I agree 100% here. *Especially* if your goal is to run NetBSD or Linux
or (insert popular Unix-like free OS here). These OS's simply don't
fit well into the 16-bit virtual address space of an -11 (2.11 BSD
has many of the features of modern Unices, but doesn't have the wastage
found in NetBSD or Linux).
A small, RISC-ish instruction set is perfect for implementing NetBSD
on. Things get a bit more complicated as you add the necessary memory
management, of course!
--
Tim Shoppa Email: shoppa(a)trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
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Bethesda, MD, USA 20817 Fax: 301-767-5927