Yesterday, UPS delivered a medium-sized box to my door; it was the V60/V70
User's Manual, plus some data sheets, and a big white binder to hold all of
it. The stuff is all labelled "Preliminary Information", and the manual is
dated November, 1986. This manual actually covers the V60; the V70 is present
only in data-sheet form, but is supposed to be architecturally identical to
the V60.
I want to share some impressions, maybe start some discussions, perhaps learn
of existing machines using th[is|ese] chip[s]. I do not work for, represent,
or have anything to do with NEC other than having received these manuals;
also, these are personal opinions and do not have anything to do with
Ungermann-Bass, whose machine I am posting this from.
The V60 is a very vax-ish arch, with a V20/V30 emulation mode (which, if you
recall, means it can run Intel 8086/8088 software). [Note: 8086/8088 and
the word "Intel" are probably trademarks of Intel Corp, whose full name I
do not remember and who, like NEC and UB, I do not represent here.]
The chip has 32 general-purpose registers, four execution levels, four AST
modes (AST = asynchronous system trap, a la VAX/VMS, (tm) Digital Equip, etc),
three-level VM paging, hardwired 4KB pages, 16MB max real memory addressing
(4GB virtual, per virtual address space), lots of addressing modes (including
'bit' addressing of bit strings up to 4 gigbits long, or bit fields of up to
32 bits, either can be on aribtrary bit boundary).
The V70 is the same chip, but with a 32-bit address bus, and therefore a
maximum real memory of 4GB. The part numbers of these chips are "uPD706xx"
where xx=16 for the V60 and xx=32 for the V70. Both chips run at "up to"
20MHz, currently.
This thing is very, very CISC. It's more like a VAX than the VAX is...
It doesn't have a 'POLYx' instruction, but it has ANDNBS, for "AND Complemented
Bit String"... :-)... It has more or less all the addressing modes that the
VAX has.
Comparisons
-----------
I have not used any system containing this chip, and I don't know if they are
even shipping. Therefore, and comparison between the V60/V70 and anything
else has to be taken with a few Kg of NaCl.
In terms of overall elegance, I prefer this chip to the National 32016 and
32032. I have not seen the NS32332 or 32532, so I can't comment on those...
I'm very fond of the Fairchild Clipper, but since the Clipper purports to be
a RISC machine, it doesn't make sense to compare it to the V60/V70. [Note:
Fairchild and Clipper are very probably trademarks of Fairchild, Shlumberger,
or National Semiconductor, depending on the state of the Fairchild-National
deal by the time you read this].
I think this machine has more goodies to it than the VAX has. Not that I
can think of any good reason to have 32 registers instead of 16 (which is
what the VAX has); however, most of what the VAX arch has, the V60/V70 seems
to have more of. Especially useful to the V60 in this comparison, is the
ability to run 8086 code without coprocessor boards...
I have a generally low opinion of the Intel 4004/8008/808[05678]/80[123]86
family; this is mostly because I do not like load/store architechtures.
There are other reasons, available upon request... The 80386 has finally
added paging, which was my major complain against its predecessors; it has
a "virtual 8086" mode, which made "DOSMerge" (doubtlessly someone's (tm),
but other than Microport I don't know whose...) a possibility, which makes
it possible to run 8086 code in a UNIX environment, which is useful if
inelegant. The V60/V70 has its V20/V30 emulation mode, which matches the
386's "Virtual 8086 mode"; once I cancel these two out, the V60/V70 with
its addressing modes and GP registers and the like wins clearly.
Summary of Disclaimers
----------------------
If I left your favorite CPU out, send me some mail or compare them yourself!
If I mentioned any trademarks without giving credit, I apologize. If you've
gotten this far without fully believing that I represent only myself, there's
nothing more I can do.
Summary of V60/V70
------------------
I like CISC. (I also like RISC.) Of the CISC machines I've heard of, the
V60/V70 stands out as about the most elegant and neat and nifty of the lot..
I would very much like to see a NUBus (tm of Texas Instruments, I'll bet)
machine with a V70 at its heart, running a System-Vr3 UNIX (tm of AT&T)
OS with TCP/IP (tm of DOD?) in done Streams (AT&T again), and something like
DOSMerge (tm of ???)... If anyone knows of ANY machine based on a V70 and
available in this country, please send me mail about it. If anyone wants
to build and sell one, I'm availabvle for software consulting :-) :-)...
--
Paul Vixie
Consultant Work: 408-562-7798 v...@ubvax.ub.com
Ungermann-Bass Home: 415-647-7023 ames!pyramid!ubvax!vix
Santa Clara, CA <<I do not speak for Ungermann-Bass>>
-- Tim Olson
Advanced Micro Devices
(t...@amdcad.amd.com)