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- Current Meeting : bsilverio/mtgs/ibmpc (ibmpc)
- Chairman : bsilverio
- Current xcn : [0400]
- New transactions: NONE
-
- Forum: p 632
- [0632] ( 39 lines) bsilverio 02/22/86 17:12 ibmpc
- Subject:RE:NEC V20 Clock Cycle Times
- *( from Multics ibmpc meeting on 02/22/86 )*
-
- Date: 15 Oct 1985 09:33:08 PDT
- From: Jeff La Coss <JLACOSS@USC-ISIB.ARPA>
- To: info-ibmpc@USC-ISIB.ARPA
- cc: JLACOSS@USC-ISIB.ARPA
-
-
- somebody wanted reassurance from a hardware type that a v-20 would
- run in a pc? simple - burn a couple extra bucks/throw away a bit of
- potential speed/get the 8mhz version. works great.
-
- generally speaking, the reason clocks are spec'ed at 50% duty cycle
- is because they are counting on both the rising and falling edges of
- the clock to shuffle data along some series of dynamic devices. thus
- if the clock looks like
-
- _ _
- ___| |___________| |_______
-
- rather than
-
- ______ ______
- ___| |______| |_______
-
- data set into, say, the master stage of a flip-flop might not
- (probably won't) have time to propagate through the present stage to
- be stable at the input of the slave stage, which is clocked by the
- falling edge. faster devices allow you to cheat on clock symmetry as
- long as the shortest part of the actual clock cycle meets the
- shortest-duration spec for the device.
-
- jeff
-
- p.s. I've heard a bunch of conflicting noise re: how NEC made the
- v-20. If the ripped-off microcode/pla story is false, NEC sure stuck
- it to Intel....
-
- ----[0636]----
- ----[0632]----
-
-
- Forum: tss page -off
-
- Forum: p 619:621
- [0619] ( 16 lines) bsilverio 02/22/86 17:11 ibmpc
- Subject:NEC V20 and Duty Cycle Query
- *( from Multics ibmpc meeting on 02/22/86 )*
-
- Date: Sat, 12 Oct 85 12:03 EDT
- From: Hess@MIT-MULTICS.ARPA
- To: INFO-IBMPC@USC-ISIB.ARPA
-
- Can someone interpret the NEC V20 duty cycle message for a non-hardware
- person? To me, a duty cycle exceeded on a piece of mechanical equipment
- means it dies from overwork. Does this message mean that one's clock
- chip will catch fire? Or does it just mean that if you plug in a V20
- that it might stop performing correctly for no apparent reason and need
- to be rebooted?
-
- Brian
-
- ----[0623]----
- ----[0619]----
-
- [0620] ( 20 lines) bsilverio 02/22/86 17:11 ibmpc
- Subject:NEC V20 Clock Cycle Times
- *( from Multics ibmpc meeting on 02/22/86 )*
-
- Date: 12 Oct 1985 02:52-PDT
- From: William "Chops" Westfield <BillW@SU-SCORE.ARPA>
- To: info-ibmpc@USC-ISIB.ARPA
-
-
- Someone warned that the NEC v20 clock was 50% duty cycle, and that
- the minimum clock high time of 85 nS was violated by the IBMPC,
- which provided about 71 nS. Well, My NEC v20 data sheet (dated
- March, 1985) says that the minimum clock high time is 69 nS,
- and not 85 nS, which is closer than it ought to be to the 71 nS
- in the IBM PC, but is pretty likely to work.
-
- The minimum clock high time on the 8Mhz part is 50nS, so things
- may be tighter in an 8MHz system.
-
- BillW
-
- ----[0624]----(more)
- ----[0620]----
-
- [0621] ( 23 lines) bsilverio 02/22/86 17:11 ibmpc
- Subject:RE:NEC V20 Clock Cycle Times
- *( from Multics ibmpc meeting on 02/22/86 )*
-
- Date: Mon, 14 Oct 85 12:26:00 PDT
- From: walton%Deimos@CIT-Hamlet.ARPA
- To: info-ibmpc@usc-isib.arpa
-
-
- Within the last two weeks, I called NEC Mountain View, 415-960-6000, and
- received a copy of the May 1985 "Preliminary Information" on the V20 and
- v30, both 5 and 8 MHz versions. This is a nicely bound manual, complete
- with a table of all the opcodes, though NEC uses different mnemonics than
- Intel to avoid charges of copyright infringement. Page 7 of this document
- calls for the minimum clock high time to be 69 ns and low time to be 90 ns
- for the 5 Mhz chip, a 43% (?) duty cycle. The former number is within,
- though perhaps uncomfortably close to, the 71 ns for the Intel 8284 clock
- chip. The 8 MHz version values are 50 and 60 ns respectively, a 45% duty
- cycle. The V30 spec quotes the same numbers.
-
- Stephen Walton
- Caltech Solar Astronomy
- walton%deimos@cit-hamlet
-
- ----[0625]----(more)
- ----[0621]----
-
-
- Forum: p 590
- [0590] ( 38 lines) bsilverio 02/22/86 17:09 ibmpc
- Subject:NEC V20 Warning
- *( from Multics ibmpc meeting on 02/22/86 )*
-
- From: "Raymond D. Dunn" <ray@othervax.uucp>
- Date: 9 Oct 85 19:02:54 GMT
-
-
- Although many, including myself, are successfully using an NEC V20 as a
- direct replacement for the Intel 8088 in our PC's, it looks as if this may
- not be a good idea in all but a hacking environment.
-
- I am indebted to my colleague Humphrey Brown, for the following information:-
-
- "The following caution should be issued in connection with the widely touted
- NEC V20 microprocessor (P/N 70108) as a plug-in upgrade replacement for the
- 8088 in personal computers.
-
- The specification for the V20 calls for a clock with a 50% duty cycle. The
- clock driver for the 8088 delivers a clock of 33% duty cycle. NEC's data
- sheet for the V20 specifies a minimum clock high time of 85nS and a low time
- of 90nS. Intel gives a minimum clock high time for the 8284 of
- 1/3 tclcl+2nS, which for a clock frequency of 4.77Mhz, yields 71nS.
-
- While the chances are that this will work anyway, those who wish to try it
- should note that there are no guarantees.
-
- I have'nt got the data sheet for the 8Mhz part yet, but by judicious
- extrapolation, that part will require a clock high time of about 48nS, thus
- that part of the clock requirement will be met. However, NEC are quite
- explicit in their data sheets as to the need for a 50% duty cycle.
-
- The solution to the mismatch between the Intel clock generator and the NEC
- processor might be to also plug in the NEC clock driver (P/N 71011) in place
- of the 8284, since it appears to be pin-compatible, but note that the 71011
- divides the external frequency by 2, not 3 as for the 8284."
-
- Ray Dunn. ..philabs!micomvax!othervax!ray
-
- ----[0594]----
- ----[0590]----
-
-
- Forum: p 537
- [0537] ( 16 lines) bsilverio 02/17/86 15:09 ibmpc
- Subject:V20 Opcodes Prepare & Dispose
- *( from Multics ibmpc meeting on 02/16/86 )*
-
- Date: Tuesday, 1 Oct 1985 12:29:17-PDT
- From: dantowitz%eagle1.DEC@decwrl.ARPA (David Dantowitz -- LTN2-2/H07)
-
-
- There have been many notes on the V20 and its extended instruction
- set, but could someone present a more explicit description of what
- the PREPARE and DISPOSE opcodes do ?
-
- David Dantowitz
- 617-486-6957
-
- [Aren't these extended Intel instructions from the 186 and 286? -wab]
-
- ----[0541]----
- ----[0537]----
-
- Forum: p 422
- [0422] (184 lines) bsilverio 02/17/86 14:59 ibmpc
- Subject:NEC V30: Availability, Benchmarks, Info
- *( from Multics ibmpc meeting on 02/16/86 )*
-
- From: Kim DeVaughn <kim@mips.uucp>
- Date: 19 Sep 85 18:03:03 GMT
- To: info-ibmpc@usc-isib.ARPA
-
-
- By the way, the actual NEC part numbers for the V30
- series of chips are:
-
- uPD70116D-8 8 MHz, ceramic
- uPD70116D-5 5 MHz, ceramic
- uPD70116C-8 8 MHz, plastic
- uPD70116C-5 5 MHz, plastic
-
- (Replace the "16" with "08" and you get the V20 (8088 compatible) p/n's.)
-
- NEC's address (so you can get a spec) is:
-
- NEC Electronics, Inc. ph: 800-632-3532 in California
- 401 Ellis St. 800-632-3531 elsewhere
- PO Box 7241
- Mt. View, CA 94039
-
- Note: I am not associated with any of the above companies, except as a
- satisfied customer.
-
- Ok, now for some quick-and-dirty before/after benchmark numbers:
-
- System: Fujitsu u-16s w/8087 (8 MHz)
- SCP: MS-DOS 2.11
- Compiler: TurboPascal 3.01A (w/8087 support)
-
- Benchmark: program bench(output);
-
- var
- i,j,k,l: integer;
- r: real;
- s: string[100];
- t,u: string[50];
-
- begin
- i := 0;
- r := 0.0;
- s := '';
- t := 'ABCDEFGHIJKLMNOPQRSTUVWXYABCDEFGHIJKLMNOPQRSTUVWXY';
- u := 'abcdefghijklmnopqrstuvwxyabcdefghijklmnopqrstuvwxy';
-
- repeat until keypressed; {start timing when a key is hit}
-
- for j := 1 to 1000 do
- for k := 1 to 1000 do {1 to 50 for string test}
- for l := 1 to 10 do
- {one of: }
- i := i + 1; {integer}
- {r := r + 1.0;} {real}
- {s := t + u; } {string assign/concatinate}
-
- writeln(^G,i{or r, or s}); {stop timing when the bell rings}
- end.
-
-
- Results: | 8086 | V30 | %-improvement
- ---------------------------------------------------------
- integer | 150.75 | 144.30 | 4.3%
- real | 1489.24 | 1357.94 | 8.8%
- string | 497.50 | 296.25 | 40.5% <---- !!
- | | |
- Mgen + | 1012.14 | 935.84 | 7.5%
- Msho ++ | 23.09 | 18.35 | 20.5%
-
- Times are in seconds.
- + Mgen is a Mandelbrot set generating program (compute intensive).
- ++ Msho is a display routine for Mgen's data (data-move intensive).
-
- The machine sucessfully ran all the diagnostics, floppy and hard-disk tests,
- rupt driven communication/modem program, etc. In short, the s/w couldn't
- tell the difference (obviously, there were no s/w timing loops in anything
- I ran ... at least none that were critical).
-
- Subjectively, MASM seems to run about 20%-30% faster, and scrolling thru text
- in various editors is quite noticeably faster. I am a little surprised by
- the integer vs. real results (I expected to see the least improvement in code
- that uses the 8087); I haven't looked at the code Turbo generates tho. In
- any case, a performance improvement of 15%-20% for average, interactive work
- is well worth $21.51, I'd say (and the chip was only slightly warm after a
- couple of hours of experimentation)!
-
-
- Here's a look at the "extra" instructions in the V30 and V20 (note that these
- are NEC's mnemonics):
-
- 80186 compatible: PUSH imm . pushes immediate data onto the stack
- PUSH R . pushes 8 general registers onto stack
- POP R . pops 8 general registers from stack
- MUL imm . executes 16-bit multiply of register
- or memory contents by immediate data
- SHL imm8 . shifts/rotates register or memory by
- SHR imm8 immediate value
- SHRA imm8
- ROL imm8
- ROR imm8
- ROLC imm8
- RORC imm8
- CHKIND . checks array index against
- designated boundaries
- INM . moves a string from I/O port to mem
- OUTM . moves a string from mem to I/O port
- PREPARE . allocates an area for a stack frame
- and copies previous frame pointers
- DISPOSE . frees the current stack frame on a
- procedure exit
-
- NEC unique: INS . insert bit-field
- EXT . extract bit-field
- ADD4S . adds packed decimal strings
- SUB4S . subtract one packed decimal string
- from another
- CMP4S . compares two packed decimal strings
- ROL4 . rotates one BCD digit left thru AL
- lower 4 bits
- ROR4 . rotates one BCD digit right thru AL
- lower 4 bits
- TEST1 . tests a sspecified bit; sets/resets
- zero-flag
- NOT1 . inverts a specified bit
- CLR1 . clears a specified bit
- SET1 . sets a specified bit
- REPC . repeats next (string) instruction
- until carry-flag is cleared
- REPNC . repeats next (string) instruction
- until carry-flag is set
- FP02 . additional float-pt processor call
-
- 8080 emulation mode: BRKEM . start 8080 emulation mode
- RETEM . return from emulation mode
- CALLN . call native-mode (V30) subroutine
- from within 8080 emulation mode
- (use normal RETI to return)
-
-
- Looks like NEC just may have developed the "Z-80" of the 8086-style
- 16-bitters ...
-
- Enjoy!
-
- /kim
-
- "The difference between science nd the fuzzy subjects is that science
- requires reasoning, while those other subjects mearly require scholarship."
- -- Lazarus Long
-
- [generic disclaimer]
- --
-
- UUCP: {decvax,ucbvax,ihnp4}!decwrl!mips!kim
- DDD: 415-960-1200
- USPS: MIPS Computer Systems Inc, 1330 Charleston Rd, Mt View, CA 94043
-
- ----[0426]----
- ----[0422]----
-
-
- Forum: p 399:401
- [0399] ( 20 lines) bsilverio 02/14/86 13:28 ibmpc
- Subject:NEC V20 and Other 8088-Family Chips in CMOS?
- *( from Multics ibmpc meeting on 02/13/86 )*
-
-
- From: Gordon Letwin <microsoft!gordonl@uw-beaver>
- Date: 16 Sep 85 14:33:59 GMT
-
-
- I installed a NEC 8088-look-alike in my homebrew system, not because
- its 7% faster (as measured) but because its CMOS and drinks less juice.
- (130 ma to 30 ma). The question is, are CMOS equivalents of the other
- system chips available? The 8284, the 8205, the 8155, etc., etc.
- If anyone knows of a manufacturer of such CMOS goodies, and maybe
- part #'s, please let me know via email.
-
- thanks
- gordon letwin
-
- uw-beaver!microsoft!gordonl
-
- ----[0403]----
- ----[0399]----
-
- [0400] ( 14 lines) bsilverio 02/14/86 13:28 ibmpc
- Subject:NEC V20 and 8087
- *( from Multics ibmpc meeting on 02/13/86 )*
-
- Date: Thu 19 Sep 85 14:34:27-PDT
- From: Doug <Faunt%hplabs.csnet@CSNET-RELAY.ARPA>
- To: INFO-IBMPC@usc-isib.arpa
-
- I've got a V20 installed in a Faraday XT clone, with an 8087, and
- have not seen any problems so far. There has been some noticeable
- speed-up in large assemblies, and Dbase applications.
- ...!hplabs!faunt faunt%hplabs@CSNET-RELAY.ARPA
- -------
-
-
- ----[0404]----
- ----[0400]----
-
- [0401] ( 19 lines) bsilverio 02/14/86 13:28 ibmpc
- Subject:NEC V20 in a Seequa Chameleon
- *( from Multics ibmpc meeting on 02/13/86 )*
-
- Date: Friday, 20 Sep 1985 10:26:15-PDT
- From: dantowitz%eagle1.DEC@decwrl.ARPA (David Dantowitz -- LTN2-2/H07)
-
- I recently received my V20 and installed it in my Seequa Chameleon.
- The new CPU works well with my 8087 and was easily installed. The Tech
- people at Seequa were not sure that the CPU would function properly, but
- thus far it appears to work fine. I have experienced only one problem
- with software and that is that the program "Lode Runner" will not function
- on my V20. This is a game by Broderbund Software, and although it loads
- fine and will display the high scores, the program hangs when it tries
- to start up a new game. If anyone with a V20 has run this program
- please let me know, as it could also be a Chameleon related problem.
-
- David Dantowitz
- 617-486-6957
-
- ----[0405]----
- ----[0401]----
-
-
- Forum: p 387:388
- [0387] ( 76 lines) bsilverio 02/14/86 13:25 ibmpc
- Subject:NEC V20 for 8088 and 8087
- *( from Multics ibmpc meeting on 02/13/86 )*
-
- From: Kim DeVaughn <kim@mips.uucp>
- Date: 13 Sep 85 22:46:26 GMT
- To: info-ibmpc@usc-isib.ARPA
-
- [ ... ]
-
- > <>When I bought an 8087 to put in my IBM PC, it came with a new 8088.
- > I was told to replace the 8088 when I put in the 8087 because the old
- > 8088 might not work properly with the 8087.
- > <>Question: Is this kind of matching really necessary, and, if so,
- > does one have to worry about replacing an 8088 with a V20 in a system
- > with an 8087? (Also same question for 80286, V30, 80287.)
-
- Ummm, let's see if I remember this correctly ...
-
- It seems that in a very early release of the 8088 (8086, both, ?), there
- was a bug that could cause problems when altering a segment register. The
- most common manifestation was in restoration of the SS:SP reg pair from
- a previously stored pair of values such as:
-
- mov SS,StakSegSav
- mov SP,StakOffSav
-
- The 808x chips are designed such that an interrupt (should one occur) will
- not be recognized immediately after the seg-reg altering instruction, but
- will be held pending until after the execution of the instruction that
- *follows* it has completed. This is so you don't end up with a meaningless
- SS:SP pointer, for example.
-
- Well, these early chips would go ahead and take the rupt immediately, which
- led to an occasional crash ... a tough one to isolate, I might add.
-
- I believe that the inclusion of a new 8088 with the 8087 purchase was just
- used as an opportunity to try and purge the early chips out of as many
- systems as possible. While it is true that the 8087 can be setup to
- generate a rupt on various error conditions (so a user written handler can
- try to clean things up), in practice, I believe most packages rely on the
- internal 8087 error-handlers (defined as part of the IEEE-754 standard).
-
- In summary, I would not expect a problem with the V20/V30 chips, as the
- 808x architecture is very well understood now ... of course there may be
- other surprises lurking in this new implementation of (and extension to)
- that architecture. Now if I can just get my hands on an 8 MHz V30 ...
-
- BTW ... there *was* a release of PC-DOS that had a related problem. There
- were several places in the code where the programmer coded:
-
- mov SP,fooPlace
- mov SS,barPlace
- instead of:
-
- mov SS,...
- mov SP,...
-
- I don't recall the particular release, and I *think* it was only for the
- PC-Jr. There was a set of patches to correct this problem published in
- "PC Tech Journal" magazine sometime within the past year or so. Anyone
- experiencing occasional, unexplainable, un-reproducable crashes might want
- to check this out.
-
-
- /kim
-
- "You can have peace. Or you can have freedom. Don't ever count on having
- both at once." --- Lazarus Long.
-
-
-
- --
- UUCP: {decvax,ucbvax,ihnp4}!decwrl!mips!kim
- DDD: 415-960-1200
- USPS: MIPS Computer Systems Inc, 1330 Charleston Rd, Mt View, CA 94043
-
- ----[0391]----
- ----[0387]----
-
- [0388] ( 47 lines) bsilverio 02/14/86 13:25 ibmpc
- Subject:NEC chips and 1.2MB diskettes
- *( from Multics ibmpc meeting on 02/13/86 )*
-
- From: lotto%lhasa@harvard.ARPA
- Date: 15 Sep 85 10:42 EDT
- To: harvard!info-ibmpc@usc-isib.ARPA
-
- To prevent any further requests for telephone numbers,
- here is the number from the NEC '84 data book:
-
- 415-960-6000
-
- Ask them for the U.S. (or other) rep near you. Ask nothing else
- of these people, they are not likely to help you much.
-
- Phone your rep. and ask for the distributor(s) near you.
- You may also ask these people for literature. Request by the actual
- part numbers:
-
- V20 = uPD70108Dx where x= 5 MHz or 8MHz
- V30 = uPD70116Dx
-
- There are users manuals as well as data sheets. Also there is
- preliminary documentation on the V40/V50. These things contain
- everything but the kitchen sink. They are available as prototype
- boards only at this time. So as not to waste a phone call, you can
- also ask for uPD765 floppy disk controller specs (the IBMPC board).
- You never know when it may come in handy...
-
- Anyway, one of the distributors will be able to sell you
- <1000 V20's or V30's. Be forwarned, the V30 is in rework at this
- moment and you will encounter significant delays. First price break
- is at 25 pieces. The V20 was quoted to me at $22.30 1-24 and $18.20
- 25-?.
-
- Of course, there is the "back door" route to the
- distributor, look him up in the yellow pages. Good luck.
- ____________
-
- Gerald Lotto - Harvard Chemistry Dept.
-
- UUCP: {genrad,cbosgd}!wjh12!h-sc4!harvard!lhasa!lotto
- {seismo,harpo,ihnp4,linus,allegra,ut-sally}!harvard!lhasa!lotto
- ARPA: lotto@harvard.EDU
- CSNET: lotto%harvard@csnet-relay
-
-
- ----[0392]----
- ----[0388]----
-
-
- UUCP: {decvax,ucbvax,ihnp4}!decwrl!mips!kim
- DDD: 415-960-1200
- USPS: MIPS Computer Systems Inc, 1330 Charleston Rd, Mt View, CA 94043
-
- ----[0366]----
- ----[0362]----
-
- [0363] ( 18 lines) bsilverio 02/14/86 13:21 ibmpc
- Subject:NEC V20 When 8087 is Used?
- *( from Multics ibmpc meeting on 02/13/86 )*
-
- From: Henry Schaffer <hes@ecsvax.uucp>
- Date: 10 Sep 85 20:21:03 GMT
-
-
- When I bought an 8087 to put in my IBM PC, it came with a new 8088.
- I was told to replace the 8088 when I put in the 8087 because the old
- 8088 might not work properly with the 8087. I didn't feel like
- experimenting, so I did the replacement.
-
- <>Question: Is this kind of matching really necessary, and, if so,
- does one have to worry about replacing an 8088 with a V20 in a system
- with an 8087? (Also same question for 80286, V30, 80287.)
-
- --henry schaffer
-
- ----[0367]----(more)
- ----[0363]----
-
- [0364] ( 16 lines) bsilverio 02/14/86 13:21 ibmpc
- Subject:RE:NEC V20 When 8087 is Used?
- *( from Multics ibmpc meeting on 02/13/86 )*
-
- From: Doug Hall <hall%ittral.uucp@brl>
- Date: 13 Sep 85 01:28:22 GMT
-
-
- I am using the NEC V20 in my ITT Xtra (a little known but very nice
- MS-DOS machine) with the 8087 co-processor. I have had no problems
- with it. Anybody want to buy a used 8088? ;-)
-
- Douglas Hall
- ITT Telecom
- Raleigh, NC
- ittatc!ittral!hall
-
- ----[0368]----
- ----[0364]----
-
-
- Forum: p 340:342
- [0340] ( 20 lines) bsilverio 02/14/86 13:18 ibmpc
- Subject:RE:NEC V20
- *( from Multics ibmpc meeting on 02/13/86 )*
-
- Date: 9 Sep 1985 10:06:32 PDT
- From: Barry Megdal <BARRY@CIT-20.ARPA>
-
-
- Before everyone rushes out to replace their 8088's with NEC V20's:
-
- I just replaced the 8 mhz 8088 in my Leading Edge, with the 8 mhz version
- of the NEC V20. It works fine, but the measured performance improvement
- was 4% for a large assembly with the Microsoft Macro Assembler, and
- 10% for a CPU-bound Lotus 123 task (a large data fill). Ok for $20 perhaps,
- but hardly in the 25-100% range. I am sure that test cases can be
- constructed that will yield 25% and more, but what about real examples?
- Or am I somehow seeing a different result due to the 8mhz part and/or
- the Leading Edge?
-
- -Barry
-
- ----[0344]----(more)
- ----[0340]----
-
- [0341] ( 43 lines) bsilverio 02/14/86 13:19 ibmpc
- Subject:RE:NEC V20
- *( from Multics ibmpc meeting on 02/13/86 )*
-
- Date: Wed 11 Sep 85 11:07:17-EDT
- From: Gern <GUBBINS@RADC-TOPS20.ARPA>
-
- I have a few comments on the NEC V20 'improved' 8088.
-
- The NEC V20 is a CMOS IC that is pin and software compatible superset
- of the Intel 8088. Aside from the addition of extra instructions
- (The Z-80 superset in the 8080 CP/M world haunts...), the NEC V20
- has a separate ALU to calculate the address, instead of the Intel 8088
- having to take extra clock cycles to reuse the 'core' ALU. This
- WILL give a significant increase in thruput. The Intel 80186 and
- Intel 80286 also use this separate address ALU. HOPEFULLY, Intel
- will come out with an 8088 pin compatible 80188.
-
- NEC has been producing 8088 CPUs for some time now - AND THEY DO NOT
- HAVE A LICENSE FROM INTEL TO DO SO (At least the last time I checked).
- Downright illegal. Even worse, these PIRATE NEC 8088s don't quite
- work right, the 8087 support is messed up and won't work at all. Do
- note that AND, National (I think) ARE Licensed 8088 producers, and
- a few companies (IBM being one) are licensed to produce 8088s for their
- own use and products.
-
- Now NEC has improved their stolen 8088 (and 8086, the NEC V30) with the
- address ALU idea from the Intel 8018x. Currently Intel is trying to sue
- NEC and I hope that they win. I also hope that Intel gets on the ball
- and properly improves the 8088/8086 with a similar thruput increase.
-
- Cheers,
- Gern
-
- [A longer version of this message appeared in INFO-HZ100. INFO-IBMPC
- is limited to technical discussions of this chip. Hopefully we can
- determine exactly what the differences are. BTW I have one installed
- with an 8087 and haven't found any problems even though I use
- floating point all the time. I am sure INFO-LEGAL (or is it law?)
- would welcome a discussion of pirate hardware. INFO-IBMPC doesn't
- welcome such a discussion as these digests are too large already even
- though I throw away 75% of the messages that arrive here. -wab]
-
-
- ----[0345]----(more)
- ----[0341]----
-
-
- Forum: p 338
- [0338] ( 21 lines) bsilverio 02/14/86 13:18 ibmpc
- Subject:RE:NEC V20
- *( from Multics ibmpc meeting on 02/13/86 )*
-
- Date: Sun 8 Sep 85 08:29:45-PDT
- From: Steve Dennett <DENNETT@SRI-NIC.ARPA>
-
-
- Well, I bought an NEC V20 from JDR Microdevices at the PC Faire last Friday.
- Took it home and with some trepidation (felt like I was doing heart surgery
- on my only child) put it into my Compaq transportable.
-
- After everything was back together, I turned it on and began trying software.
- So far no problems with any, including communications software (which often
- seems to be sensitive to timing). I haven't measured the speedup, but it
- is noticeable; some of my old games are challenging again! Not bad for
- ~$21.
-
- Steve Dennett
- dennett@sri-nic.arpa
-
-
- ----[0342]----(more)
- ----[0338]----
-
-
- Forum: p 291:293
- [0291] ( 37 lines) bsilverio 02/14/86 13:10 ibmpc
- Subject:NEC V20, V30 Replacements for Intel 8088/86
- *( from Multics ibmpc meeting on 02/13/86 )*
-
- From: Bob Hartman <rch@vaxine.uucp>
- Date: 6 Sep 85 16:49:48 GMT
- To: info-ibmpc@usc-isib.ARPA
-
-
- To those of you that saw my posting last week about the new NEC V20
- and V30 chips, thanks for responding and telling me where to get one. I got
- mine through JDR Microdevices ($20.95 - advertised in BYTE).
-
- As you may or may not know, the V20/V30 chips are 8088/86 look-alikes
- that are sold by NEC. The differences are many, but mainly in that the V20/30
- are SUPERSETS of the 8088/86 family. For example, they support 8080 emulation,
- contain the 80186 instruction set, plus a bunch of new instructions. The real
- kicker is that the V20 is faster than the 8088 in most instructions, and the
- rest of the instructions are at the same speed. Big gains are in relative
- addressing modes where the V20 takes 2 clock cycles for the address compared
- to the 8088's 5-12 cycles. Anyway, the moral of the story is that you can
- buy this chip, stick it into your PC in place of the 8088, put the cover back
- on, and everything will work as before. The only difference is that you will
- get a 5-100% improvement in performance depending upon the software being used!
- I found that in general I was getting about 25% improvement. For $20.95, you
- can't beat this system upgrade. I checked out every program I own (I run the
- UN*X Gateway BBS - Fido 101/101, and I have about 20MB of programs), and they
- all ran perfectly (and yes, that includes with and without an 8087 chip). The
- funny thing is that unlike the AT, programs that use the timer interrupt do not
- run faster. This is because the clock frequency is the same, just the
- instructions execute faster.
-
- Hope this helps people who were wondering.
-
- - Bob Hartman -
- UUCP: {decvax,ihnp4}!encore!vaxine!rch
- BBS: Fido 101/101 - (603) 888-5433 300/1200/2400 baud
-
- ----[0295]----
- ----[0291]----
-
-
- [0293] ( 11 lines) bsilverio 02/14/86 13:10 ibmpc
- Subject:NEC V20
- *( from Multics ibmpc meeting on 02/13/86 )*
-
- Date: Friday, 6 Sep 1985 13:10:05-PDT
- From: dantowitz%eagle1.DEC@decwrl.ARPA (David Dantowitz -- LTN2-2/H07)
- To: info-ibmpc@isib.ARPA
-
-
- I am curious if anyone has tried the NEC V20 on Seequa's Chameleon
- or any of the other IBM PC compatible.
-
- ----[0297]----(more)
- ----[0293]----
-