Category : Miscellaneous Language Source Code
Archive   : NEC-V20.ZIP
Filename : NECV20B.ALL

Update B, 10/16/85 NEC V20/V30 Overview
NECV20B.ALL


(Please upload this file to other systems. It is a summary of what most
people are trying to find out about the NEC V20/V30 chips)


This file is a collection of information on the CMOS NEC V20 and V30
microprocessors. The V20 reblaces the 8088 from Intel, the V30
replaces the 8086.

Topics covered are:

How and where to purchase, plus quantity pricing.

General features of interest to PC owners.

Some technical features of the chip.

Extracts of other writeups on the chip.

Summary of incompatibilties.



The microprocessor chips are available as follows:

(Quantity pricing listed below)

Component - What it Replaces - Price
----------------------------------------------------------------
NEC V20 5 mhz - 8088 in standard PC and compatibles - $24.95
NEC V20 8 mhz - 8088 in PCs with higher clock speed - $29.95
NEC V30 5&8 mhz - any 8086 in any application - $29.95
NEC V20/V30 user guide (with v20/v30 purchase only) - $ 5.00
NEC V20/V30 summary documentation (with purchase only) - $ 2.00
16 mhz crystal - Standard PC-AT crystal (33% increase)- $ 8.00

>>> QUANTITY PRICING: 6 or more of any V-Series gets a 36% DISCOUNT <<<
>>> 10 or more of any crystal gets a 50% DISCOUNT <<<

* mhz stands for "megahertz", the internal clock speed of your
computer. The standard PC/XT/Compaq/compatibles run at 4.77 mhz.


The prices listed above include:
+ All shipping and handling
+ The NEC processor
+ INSTALLATION TOOL (for removing old 8088 or 8086)
+ 90 DAY WARRANTY (Ask the competition about this one!)
+ Easy 10 minute installation
+ Installation guide.
+ Free trial use of the Exec-PC 10-line Multiuser Electronic
Bulletin Board with access to >3,000 PC programs and files.

Why order from Exec-PC? We guarantee what we sell. Our chips are never
touched by human hands as we process them. They are always shielded by
an antistatic cover, even when transferred from bulk packaging to our
test facilities and single mailers. We have a return rate below
3/10th of one percent. We include a tool that has been designed for
removing the 8088/8086 without bending any pins. No metal pry extraction
tool can guaranteee this. Metal tools can "zap" a V20/V30 if used on them!
Remember, we also include free BBS access.

Orders can either be placed by voice, modem, or mail.

Order Hotline (voice): 414-242-2173
Technical Info (msg) : 414-242-2165
Order by modem (bbs) : 414-964-5160, 10 line Exec-PC BBS.

If you wish to order by mail, include the following information
with your order:

1. Your name
2. Company name (if applicable)
3. Street address
4. City, ST Zip
5. Your phone # (home and/or work)
6. Tell us what you want (how many NEC chips, what speed, how many Crystals)
7. Include a check or money order.
or
Include your credit card type (MC/VISA)
your credit card number
your credit card expiration date
your name exactly as it appears on the card.


Send your order to: Exec-PC, Inc.
PO Box 11191
Shorewood, WI 53211


All orders are shipped same day, prepaid included in price listed above.

DEALERS and VOLUME PURCHASERS: Volume pricing is available. Please call.


Bob Mahoney
President
Exec-PC, Inc.


(End of Sales/Order Info)
-------------------------------

General Chip Discussion



The PC Speedup kit will increase the throughput of your PC by
10% to 40%, depending on the application. You can install the
kit yourself.

The heart of the PC Speedup Kit is the new NEC V20 or V30 micro-
processor. The V20 directly replaces the 8088 microprocessor, while
the V30 directly replaces the 8086 that powers some PCs.
The NEC chips perfectly emulate all of the functions of the older 8088
microprocessors, but they do things faster. How can that be possible?
The NEC chips were designed recently, taking advantage of later
technology. More complex computing structures could be squeezed into
the same package, allowing certain microprocessor tasks to take place
more efficiently. This allows the V20/V30 to outperform the 8088/8086,
all the while making your computer think it is still running an 8088 or
8086 chip.

After much testing it has been determined that all software will
run with this chip, meaning no compatibility is lost. It has
also been determined that all software runs faster. The speedup
varies with each application, but no speedup was less than 7%,
and some were as high as 100%.

As an added bonus, the NEC chips are a member of a class of chips that
use much less power and produce much less heat in operation. The
heat load and power useage in your PC will be slightly reduced
through the use of the NEC chip.

Speedup examples:

+ A 640k PC will "warmup" in 50 seconds vs 75 seconds with
an unenhanced PC.

+ Norton's Speed Index utility indicates a speed factor of 1.7
compared to 1.0 for the standard PC.

+ Most memory intensive programs show a 15% to 20%
improvement in execution times.

+ PTIMER.COM, a "clock speed checker" runs in 3.35 with
the V20, in 10 seconds with the 8088.



Special note: The NEC V-Series processors very closely duplicate
Intel products. Intel is currently in court with NEC over this close
emulation of their products. As a top NEC distributor said "You
never know when the supply will dry up. The courts may decide you
cannot get this chip in the future." Don't worry, Exec-PC has an
ample supply of chips available for immediate delivery.
You will be notified if we cannot ship your order immediately.

(End of General Chip Information)
-------------------------------

Technical PC Speedup Kit Information


In general terms, NEC achieves a performance improvement by
reducing the number of CPU cycles needed to execute certain
instructions. Thus, the same clock speed will yield more
processing power, since the V20/V30 uses fewer clock cycles to do
certain portions of its work.

8087 - The V20/V30 is 100% compatible with the Intel 8087 math
coprocessor. Exec-PC will be shipping NEC 8087 clones in the
first quarter of 1986.


+ Dedicated effective address calculation hardware
requires 2 clock cycles vs 5-12 for the older processors

+ Pin compatible with 8088/8086

+ Superset of 8086/8088 instruction set

+ Low power CMOS, requires only 15% the power used by
the NMOS chip it replaces

+ Dual internal bus vs single internal bus

+ Pre-fetch pointer vs none in 8088/8086, speeds up calls,
returns and jumps

+ Dedicated math section with new 16 bit temporary
registers, speeds up math 60% to 100%

+ Enhanced instruction set with 101 instructions,
giving 15-20 new instructions

+ Emulates the 8080 if required

+ Very low power standby mode, <50mw, as used in portable
laptop computers


Order Hotline (voice): 414-242-2173
Technical Info (msg) : 414-242-2165
Order by modem (bbs) : 414-964-5160, 10 line Exec-PC BBS.


(End of Technical Summary)
------------------------------

The following extracts were taken from electronic BBS systems.
-------------------------------------------
An upload to Exec-PC BBS:


Times to recalculate AFTER first CALC after loading file
but with new values in input cells

PC 17 SEC WITH 123 VER 1A & SYMPHONY VER 1.0; INTEL 8088
PC 13.5 SEC WITH 123 VER 1A & SYMPHONY VER 1.0; NEC V20 8088
XT 21 SEC WITH SYMPHONY VER 1.1 ;INTEL 8088; NO 8087
PC 3 SEC WITH SYMPHONY VER 1.1; INTEL 8088; WITH 8087
PC 2.25 SEC WITH SYMPHONY VER 1.1; NEC V20 8088; WITH 8087

Above done on a worksheet with three columns of 182 @PMT formulas
each, referencing a loan ammount in the first cell of each column.
@PMT uses an exponet in it's formula, shows worth of 8087

-------------------------------------------
The following note appeared recently on USENet (net.micro). It seems
to be the best summary so far of the NEC V20/30 - iAPX86/88 controversy.
I'm posting it in it's entirety:

-----------------------------------------------------------------------

From: [email protected] (Dave Tweten)
Subject: Re: NEC V20 ---> 8088
Date-Received: 16 Sep 85 08:45:42 GMT

I recently bought an NEC V20 and installed it in my Z-151, which I am
using to write this message. When I pried the 8088 out from next to my
8087, I noticed that it too had been a NEC part. Contrary to earlier
comments in this forum about NEC 8088s not working with 8087s, it had
worked flawlessly with my 8087 for the previous year.

Preliminary experience is that the V20 speeds up some programs
noticably, and has no effect on others. That is to be expected. If a
program is 8087 limited or I/O limited, speeding up the 8088 will do no
good. It has worked at least as well as the 8088 for any program I
have tried.

The only "negative" effect of the V20 is it causes Zenith's disk-based
diagnostics for CPU-board crystal frequency, and for floppy-disk driver
crystal frequency to fail. I presume the tests compare crystal cycles
against a wait-loop counter. Since the NEC V20 "waits faster" the
tests fail. Sorry, no time yet to do benchmarks.

(note on this: The above problem is encountered only when running
the Zenith diagnostics programs. That portion of the diagnostics
is not typical of other software. The function served by that
portion of the Zenith diagnostic system is better served by
external test equipment containing its own "unbiased" timer.
......Bob Mahoney)

From: Charles R. LaBrec

I haven't really heard many specifics of the NEC V20. Is it
really a case of design stealing or just a case of duplicating
the 8088 instruction set? Would someone care to enlighten me?

I don't presume to be an engineering law expert, but by no strech of my
imagination can I conceive to the V20 being an 8088 carbon copy, either
legal or illegal. The following information was gleened from Intel's
"iAPX 88 BOOK" and from the NEC document titled "V20, uPD70108,
HIGH-PERFORMANCE 16-BIT MICROPROCESSOR, PRELIMINARY INFORMATION", dated
May 1985.

. The time for a register-to-register ADD is quoted as three clocks
for the 8088, two clocks for the V20. NEC's literature claims
that is due to dual 16-bit on-chip busses for the V20, as opposed
to a single bus in the 8088. That supposedly permits two-cycle
register-register instructions (get both operands, return result),
where the 8088 uses three (get one operand, get the other, return
the result). A quick scan through the respective instruction
timing charts indicates that the relationship holds for all
trivial two-register instructions (this obviously doesn't apply to
multiply and divide).

Intel's register-register 16-bit operand, 32-bit result multiply
is quoted at 118-113 clocks. NEC's is quoted as 41-47. The
equivalent divide times are 165-184 cycles for Intel and 38-43 for
NEC. Yes, I too noticed that NEC claims to divide faster than they
multiply, and I can't explain it either.

. NEC claims to use a separate address resolution unit on the chip,
instead of using the arithmetic unit. Their effective address
calculation time is two cycles for any mode. Intel's ranges from
5 to 12, depending on mode.

. The NEC chip has an expanded instruction set. By my estimation,
it includes all the 80186 set plus several more. It has bit-field
insert and extract (perhaps useful in low level graphics?). It
can test and manipulate individual bits in memory. It has packed
decimal string add, subtract and compare. It has a BCD digit
rotate instruction. Those are the highlights (as I see them);
there are several more instructions I haven't mentioned. There is
also a complete 8080 emulation mode which interests me not at
all.

In summary, it appears to me that if the V20 is a "pirate" 8088, then
the Z-80 was a "pirate" 8080. Is our chauvinism showing?

------------------------------------

ANOTHER EXTRACT

18:33:11 9/17/1985
NEC V20 CPU chip
Triple 8088 speed.

The NEC V20 CPU chip is an 8088 CPU chip replacement. Speed improvements
of 10-40% have been claimed for the chip.

It may be that these percentage increases in speed understate the actual
improvement attributable to the chip alone, since they may include
disk operations or other operations that are not CPU-intensive.

The program CPU.COM tests the speed of a CPU with minimal RAM access
and no disk I/O. The speed of the CPU is almost TRIPLE the speed
of the native Intel 8088:

(This program is on Exec-PC under the name PTIMER.COM. ...Bob Mahoney)


-------------------
C>cpu
CLOCK SPEED CHECKER (minimal RAM access), please wait...
Execution time should be 10.00 secs if 4.77 Mhz clock & no WAITs on RAM access
Actual execution time here was 03.35 seconds
Effective clock speed = >.23 Mhz

C>
-------------------

The above effective clock speed of ">.23 Mhz" is 14.23 Mhz. Evidentally
the program CPU.COM did not anticipate double-digit clock rates.

The above test was performed on an IBM Portable PC.


Zider Brothers, San Francisco.


17:17:40 9/23/1985
NEC V20 CPU chip
PPC 70% speed improvement.

Further to the earlier note on the NEC V20 chip. Tested with the
system speed test SI in the Norton Utilities Version 3.0 on an IBM
Portable PC. Factor of 1.7 times the PC:

------------------------
C>si

SI-System Information, Version 3.00, (C) Copyright 1984, Peter Norton

IBM/PC
Built-in BIOS programs dated Monday, November 8, 1982
Operating under DOS 2.00
4 logical disk drives, A: through D:
The operating system reports 512K of memory
A test of random access memory (RAM) finds:
512K from hex paragraph 0000 to 8000
32K from hex paragraph B800 to C000
(some may be phantom memory)
BIOS signature found at hex paragraph C800
Programs are loaded at hex paragraph 1AF2
following 110,368 bytes of system memory

Computing performance index relative to IBM/PC: 1.7

C>
-----------------------------------

Zider Brothers, San Francisco.

17:21:44 9/23/1985
NEC V20 CPU chip - Pfaster286
Incompatible with Pfaster286 board.


According to a telcon with Phoenix Software Associates, the NEC V20 chip
is incompatible with their Pfaster286 coprocessor board.

The Pfaster286 software uses the PUSHA (Push All) instruction to determine
if the chip in use is the 80286 or the 8088. The 8088 gives an error if
this instruction is attempted. But the NEC V20 has implemented this
instruction (80186 instruction set) and gives no error. A revision
to the software (or hardware?) will be coming Real Soon Now.

Zider Brothers, San Francisco.

==========================================================

(End of Special Extracts)
-------------------------------

Incompatibilities:

After marketing and selling the NEC V-Series processors throughout
the US, the following incompatibilities have been encountered.
This section will be updated as more information arrives:


- Phoenix Software Associates Pfaster286 coprocessor board has a
software problem, they will fix it soon.

- Panasonic Personal Computers Senior Partner. Problem with the
8253 interupt timer. Panasonic is working on a fix so their
computers can work with the V-Series.

- Potential problem with Clipper DB III compiler. This is a really
obscure one, you may never run into it even if you use Clipper.

Note: The above problems will never be encountered by 99.9% of
the PC users who install the NEC chip. These are the ONLY problems
encountered to date.


(End of Incompatibility Section)
--------------------------------

Bob Mahoney
Exec-PC

end