Subject: Re: Is There a Port For Nec Risc Workstations?
To: Carl S Shapiro <cshapiro@ic.sunysb.edu>
From: Warner Losh <imp@village.org>
List: tech-ports
Date: 11/19/1996 22:14:12
In message <199611192043.PAA00135@sparky.ic.sunysb.edu> Carl S Shapiro writes:
: Regarding the processor, it is probably an NEC Vr4400.  I really do not
: know what the clock speed would be though.  This machine is at the least
: "mostly" ARC compliant, which means it's internals should be "mostly"
: documented.  The ACE consortium that maintained the ARC spec is very much
: dead now.  Maybe if you bother the right people at MIPS you may be able
: to find something.

There are copies floating around of the ARC Spec, at least for the
base machine and the EISA appendix.  Generally speaking, however, they
don't help much once the machine has booted and has probed its
hardware.  There are interfaces that are useful to get some
information out of the machine, but generally that work has already
been done, at least on the OpenBSD/arc port.  If anybody knows where
to get newer copies of this stuff, or additional information, I'd love
to hear from you!

The hard part comes in when you need to find out how the machine does
things like DMA, ISA Bus addresses, etc, etc, etc.  There, you are SOL
unless you can disassemble the HAL, know someone at the hardware
company who is willing to talk and who has the knowledge needed to do
the talking.  Even with the HAL disassembled, it can be non-trivial to
figure out what exactly is going on sometimes.  NEC might be able to
help you out on that, but I wouldn't be too hopeful.

So if you aren't an OS hacker, then you will likely have a long,
frustrating road ahead of you.  I know that I have had a long,
frustration, rewarding road behind me :-).

Warner