Talk:i386

Models and variants, content error?

It says the i386DX was produced with about 104mm^2 die size in the CHMOS III process and later with about 39mm^2 die size in the CHMOS IV process. For the i386SX it says it was produced with the CHMOS IV process and with about 104mm^2 die size. Are you sure the die size and/or process for the SX variant is correct? It doesn't seem to add up for me, at least.

178.24.193.37 (talk) 16:51, 11 May 2010 (UTC)

Most Important Design Choice

I don't understand how keeping the flat memory model was such a significant design choice. Upon further research, it seems that all preceding Intel chips also featured a flat memory model. —Preceding unsigned comment added by 216.27.163.78 (talk) 02:46, 21 February 2009 (UTC)

Earlier chips supported only 64KB of flat/linear/continous addressing; the 386 was the first chip which had this extended to 4GB, i.e. 65536 times as much, a very significant difference. 83.255.39.24 (talk) 20:40, 23 February 2009 (UTC)

In order to address all of the memory available in the computer using an 8086 or 80286, you had to use a segment register, which would be multiplied by 16 and added to the address register. So in order to access any given memory location within, say, the first megabyte of RAM, you need to do some maths to present the CPU with a segment:offset. The 386 provided a method of accessing all the available RAM by extending the address pointers beyond 16 bits. - Richard Cavell (talk) 06:51, 1 July 2009 (UTC)

Release

I've seen sources that say the chip was released in 1985. [[1]]. Was it really 1986 or was it 1985? Timbatron 21:42, 25 December 2005 (UTC)

The chip taped-out in October 1985 (I was there). It was not "released" until (IIRC) late 1986, as at the time there was a long lead-time between tape-out and public availability. -- Gnetwerker 08:08, 3 February 2006 (UTC)

Sorry to respond to such an old comment, but is there any citations to confirm this? Everything I've read on the Intel website points to 1985 not 1986. --Android Mouse 00:03, 15 July 2007 (UTC)

(Verifable/Validation Source) I was the Responsible Individual (RI) Research and Development Technician working on the 80386 at Intel Corporation's R&D Facility, adjacent to the Production Facility in Livermore, CA. The run yielded approximately 8 die per wafer at E-test for the first time in late 1985. With new proprietary information, the product was immediately launched into full, mass production as the world was waiting for this chip to be born--and so it was, in the third quarter of 1986. kathywinchell@gmail.com — Preceding unsigned comment added by Winchell4 (talk • contribs) 18:08, 20 June 2014 (UTC)

Sources

"Intel decided against producing the chip before then, as the cost of production would have been uneconomic." What is the basis for this assertion? The chip wasn't designed until Oct '85, this implies otherwise. -- Gnetwerker 08:08, 3 February 2006 (UTC)

Customers

I think it is significant that the first major customer was Compaq, then not a large company, rather than IBM. While I "know" this (from being at Intel), I don't have a source. Anyone? (P.s. -- The Compaq page says all of these things without attribution.) -- Gnetwerker 08:11, 3 February 2006 (UTC)

SX-DX

Does anyone know what SX and DX stand for? I heard once "Single eXecution" and "Double eXecution". But I've never seen that confirmed. warpozio 14:04, 27 March 2006 (UTC)

SX and DX means very different things, depending on processor's generation. 80386SX internally is identically the same as DX (fully 32-bit), but it has 16-bit data bus, which slowed down it's memory access performance comparing to 80386DX, which had 32-bit data bus. In this matter it's similar to Motorola 68000, which is also a 32-bit processor internally (32 bit addressation, registers, arithmetic), but also has 16-bit data bus. It was done to minimize the costs of motherboards - 68000 was out much earlier than 80386SX. Also, first 80386 of course has 32-bit data bus, thus is was the "DX", yet it wasn't called so, because 80386SX and separation between SX and DX was introduced later.

In the 486 generation processors SX versions doesn't have built-in FPU. Of course 80386 never has integrated FPU, thus 486SX at the same frequency is something like faster 80386DX (faster due architectural advances - pipelined ALU and so on). Yet, AMD has managed to produce 80386DX working at quite high frequencies (40Mhz), thus is often was faster than 486SX with lower freqs like 25Mhz.

SX and DX are mostly marketing features, which are introduced to separate lower and upper segments of market. In such meaning they are something like "Celeron" and "Pentium" trademarks used todays. Though different generations of processors use different ways to "cripple" the performance in low-cost models.

"Crippling"? That's only really something that's been done on rare occasions to meet market demand for cheaper parts that hadn't been produced in sufficient numbers (like the Durons that were Athlons with most of the cache disabled by removing a jumper wire and could be returned to full spec by bridging the contacts). Mostly it's dies which didn't pass QC for whatever reason (fault on the wafer, too close to the edge...) but it's only the part which doesn't feature in the low cost model anyway which has been damaged - e.g. part of the cache, or the hyperthreading controller. Cut a designed-in breakable link (same as used to designated them as fit for a certain speed) to disable that area and make the chip report as the cheaper member of the processor family, and it's still usable rather than being consigned to the bin. Even though the performance is so lacking you may wish that they HAD recycled it...! 193.63.174.11 (talk) 11:51, 27 April 2011 (UTC)

You didn't read the question, Mr Unsigned. You answered a question that was in your head. The gentleman wanted to know what the letters DX and SX stood for. You let him down, and that upsets me. Lupine Proletariat 14:55, 18 May 2006 (UTC)

SX - Single Word External (16-bit data bus) DX - Double Word External (32-bit data bus). —Preceding unsigned comment added by 89.243.46.113 (talk) 20:34, 6 November 2007 (UTC)

Confirmed: https://en.wikichip.org/wiki/intel/80386 170.75.140.124 (talk) 12:13, 18 July 2020 (UTC)

...and also a contraction of SimpleX and DupleX, which could be in relation to having a bus that was the same size as, or double that of the previous-gen CPUs? 193.63.174.10 (talk) 15:10, 27 October 2010 (UTC)

Untitled

This needs to be made into a disambig because there's a very important folder called I386 with the Windows installation files (called a "Windows CD-ROM image") on most modern PCs:

http://ask-leo.com/i_dont_have_an_installation_cd_for_windows_xp_what_if_i_need_one.html http://encyclopedia2.thefreedictionary.com/i386

(1) The Intel 386 CPU. See 386.

(2) The name of a CD-ROM folder. Sometimes, "i386" is used as a folder name on installation or development CD-ROMs to refer to the Intel or PC platform in contrast to other platforms that may also be supported. --Espoo (talk) 07:41, 10 November 2010 (UTC)

80287

Assembler manuals claims that original 80386 could work with 80287 processor - to save one's investments, or to allow intermediate price-and-perfomance level between FP-less sole 80386 and expensive 80386+80387 pair

A few board designs had both a DIP socket for an 80287 and a PGA socket for an 80387. Only one FPU could be installed. I've seen only one example of such a board in 29 years. It was a "full AT" size, only fit the large, horizontal desktop cases. Bizzybody (talk) 11:22, 21 February 2012 (UTC)

The Compaq board only had a 287 socket. https://stason.org/TULARC/pc/motherboards/C/COMPAQ-COMPUTER-CORPORATION-386-DESKPRO-386-TYPE-A.html

The Compaq board type B, had both 287, and 387 sockets: https://stason.org/TULARC/pc/motherboards/C/COMPAQ-COMPUTER-CORPORATION-386-DESKPRO-386-TYPE-B.html 170.75.140.124 (talk) 12:18, 18 July 2020 (UTC)

Multiply bug

OK, why delete that section? It's significant - the first Intel '32 bit' CPU didn't, you know, actually work and Intel ended up stamping thousands of chips '16 bit only'. Several important programs (eg Windows) checked for this. Lovingboth 22:30, 29 October 2006 (UTC)

Third generation x86 processor?

Isn't 80386 be the fourth generation x86 processor (8086, 80186, 80286 and then 80386)? Or is there some reason why one of these should not be regarded as a generation? Even though this article is about computing, I guess the 8086 can't be counted as zeroth generation... 213.216.199.30 21:20, 13 February 2007 (UTC)

To my understanding, the 8086, and 8088 and the 80186 are both considered chips in the first generation, similar to how the Pentium II and III are both considered sixth generation chips. Suigi 05:05, 14 February 2007 (UTC)

It would be more natural to regard only 8086 (1978) and 8088 (1979) as first generation chips, but both 80286 (1982) and 80186/188 (1982) as second generation designs. 80186 and 80286 have a great deal in common technically. /HenkeB 23:47, 18 March 2007 (UTC)

That makes more sense. It still means that the 80386 is the 3rd generation chip, thus resolving this issue. Suigi 01:12, 19 March 2007 (UTC)

Yes. /HenkeB 15:48, 19 March 2007 (UTC)

Yes. 170.75.140.124 (talk) 12:20, 18 July 2020 (UTC)

Further question is, does the 486 count as 3rd or 4th gen, as it's largely a turbocharged 386? The Pentium becomes the 4th gen if 486 is 3rd (with a genuine architecture shift)... and so, MMX and/or P-Pro becomes 5th gen? They exhibit enough difference from both the original Pentiums, and the PII/PIII line after all... 193.63.174.11 (talk) 11:45, 27 April 2011 (UTC)

1st gen 8086, 8088, 80186, 2nd, 286, 3rd 386, 4th 486, 5th pentium, 6th Pentium Pro, Pentium II, 170.75.140.124 (talk) 12:20, 18 July 2020 (UTC)

Socket

The summary box states that the 386 is a 68 pin CPU. I am fairly sure (looking at a summary from Intel docs) that the 386 DX was offered in a 132 pin PGA or PQFP format. The coprocessor, the 387, was 68 pin. Also, the 386 SX may have been offered in a 68 pin format since it had only a 16 bit external data bus.

Blackberry

Should it be noted that this chip was still used in RIM Blackberries until recently? —Preceding unsigned comment added by 86.164.161.165 (talk) 14:15, 25 December 2007 (UTC)

Disambiguation needed

A disambiguation page is needed for "i386". A search querie for this term directs to this page (the 80386 page). The term "i386" also refers to a directory used in Windows operating systems that contains files used to create an installation disk. The directory is not related to the processor used on the host machine. WWriter (talk) 22:06, 4 February 2008 (UTC)

Firstly, the directory on a Windows install disk does refer to the processor architecture. Secondly, is the directory on a Windows install disk worthy of its own article? - Richard Cavell (talk) 06:55, 1 July 2009 (UTC)

Typo found

Intel i386 SL processon <--- Should end in R, but being a newbie I can't figure out how to get at it... It's the text for the image of the SL processor I believe.

fixed. -75.69.164.125 (talk) 21:43, 21 March 2008 (UTC)

i386EX and Hubble Space Telescope

This page says that the i386EX was used in the Hubble Space Telescope. The Hubble Space Telescope was launched in 1990 (but didn't work until 1993 when the corrective mirrors were installed), but the i386EX did not come out until 1994. How can this be? Was the i386EX added on a servicing mission? —Preceding unsigned comment added by 24.167.184.128 (talk) 05:10, 22 September 2008 (UTC)

40Mhz parts?

I'm almost certain you could get 40Mhz 386 desktops - I even have gaming magazines that report it as the minimum spec for some older or less demanding titles (e.g. "40mhz 386, 25mhz 486SX or 386+FPU, or any 486DX or Pentium"). However this speed is only reported as available for embedded parts in the article. Was it an official (and possibly premium at first but eventually cheap and long-running) Intel (or AMD) 5v CPU, or was some manufacturer leveraging embedded processors in their budget-spec computers - in sufficient quantity for them to be worth mentioning instead of e.g. "well, it *will* run on a 33mhz 386, but it'll be choppy" or whatever? 193.63.174.11 (talk) 11:56, 27 April 2011 (UTC)

I had a machine from data general that came with an intel 386 @ 40MHz. I wish I still had it to provide CPU suffixes, but I know it came stock that way. — Preceding unsigned comment added by 24.63.79.245 (talk) 13:41, 3 September 2011 (UTC)

Yes, there was a 80386DX 40Mhz CPU available for desktops. I had one, never could locate a matching Mhz 80387DX. At least one company made a 80486DX2 80 Mhz CPU with the 80386 PGA pinout, but they were bloody expensive. The 40Mhz 386 was most likely a "Take that!" response to Motorola's 40 Mhz 68030 which garnered much publicity for its used in Apple's "wicked fast" Macintosh IIFX. Bizzybody (talk) 11:14, 21 February 2012 (UTC)

Look out for possible copyright violations in this article

This article has been found to be edited by students of the Wikipedia:India Education Program project as part of their (still ongoing) course-work. Unfortunately, many of the edits in this program so far have been identified as plain copy-jobs from books and online resources and therefore had to be reverted. See the India Education Program talk page for details. In order to maintain the WP standards and policies, let's all have a careful eye on this and other related articles to ensure that no copyrighted material remains in here. --Matthiaspaul (talk) 15:12, 30 October 2011 (UTC)

I have just reverted these edits by User Sachin.god, because they were a 1:1 copy paste from existing material. -84user (talk) 01:52, 1 November 2011 (UTC)

Programs written for older chips.

Some 64bit CPUs have removed support for running 16 bit software. One example is the AMD LE1620. (One of which is in the box I'm using right now.) Try to run any old DOS program on Windows XP using this CPU and you get an NTVDM error. The CPU doesn't support the x86 virtual machine, might even be incapable of booting plain old DOS. Bizzybody (talk) 11:19, 21 February 2012 (UTC)

B1 stepping bugs

There should be some discussion about the B1 stepping bugs that made opcodes fail to work if followed by specific other opcodes. — Preceding unsigned comment added by 84.243.199.239 (talk) 16:29, 10 December 2014 (UTC)

ALL 386 CPUs have the so called POPAD BUG. Description can be found on German wikipedia. English information is here: http://computer-programming-forum.com/46-asm/c4c6d67250609049.htm --62.48.72.147 (talk) 09:35, 11 October 2016 (UTC)

code

Could someone provide the assembled code for the Example Code listed? Having the actual binary (hex) code allows for code size comparisons with other processors. — Loadmaster (talk) 17:30, 29 April 2016 (UTC)

Start DOSBox or start Bochs and install FreeDOS inside it, then type the code into "debug.com" by entering "a" + [enter], when done. Type just <enter> to quit assembling and then type "d 100" to dump the hex version. Taken freely from memory. Bytesock (talk) 19:34, 29 April 2016 (UTC)

I used defuse.ca, an online x86/x64 assembler/disassembler site. Hopefully the code is correct. — Loadmaster (talk) 17:28, 4 May 2016 (UTC)

Perhaps this is what you are looking for? "55 89 E5 8B 75 0C 8B 7D 08 8A 06 46 3C 41 0F 8C FC FF FF FF 3C 5A 0F 8F FC FF FF FF 04 20 88 07 47 3C 00 0F 85 FC FF FF FF 5D C3". It's right there in the code example. Your online assembler did however return "Sorry, your input is too big or contains unsafe directives! The period (.) character must not appear anywhere in your source code.". Ooops, I see it's you that added those bytes. The online assembler did however return "Error: junk `al' after expression Error: no such instruction: `copy mov [edi],al' Error: no such instruction: `done pop ebp' " even with the old code and the comments removed. Would be interesting if x86_64 incurs a serious bloat. What platforms have you tried to compare with? Bytesock (talk) 19:02, 4 May 2016 (UTC)

Yes, I used the online assembler to produce the opcodes, which I then added to the example code in the article. My concern is that the relative conditional jump opcodes (for JL, JG, and JNE) seem a bit lengthy (6 bytes); I would expect there to be shorter equivalent versions (only 2 or 3 bytes long). — Loadmaster (talk) 21:07, 4 May 2016 (UTC)

Assembling with nasm reduced it by 12 bytes. FYI, changing esb to rsb and recompiling as 64 bit adds 7 bytes again. 68.150.137.251 (talk) 23:05, 25 November 2017 (UTC)

Requested move 28 April 2021

This section is an excerpt from Talk:I486 § Requested move 28 April 2021.[edit]

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: Moved  — Amakuru (talk) 08:55, 7 May 2021 (UTC)

---

Intel 80486 → – The official product name, etched onto every chip, is i486. WP:COMMONNAME is either i486 or Intel 486. The digit string 80486 is part of the model ID numbers, but very infrequently used to refer to the CPU family. The references cited in the article refer to the chip as either 486 or i486. Intel website nowadays calls it Intel486™; their white papers still include both i486 and Intel486 in the bulk list of their trademarks.

The article had a few undiscussed moves in the past: first to Intel i486, then to Intel 80486 (microarchitecture), then to Intel i486 (Processor), but so far never to i486, which would be in line with other CPUs having proper names: e.g. Athlon is not named AMD Athlon or AMD Athlon (Processor) or AMD K7 after the model ID number. Crash48 (talk) 18:40, 28 April 2021 (UTC)

• Support. I think the common name is just 486. If we don't use that, it makes more sense to use one of the official names. Using the model number is indeed strange, as WP only tends to use those when they are the name the general public uses.

The only thing I might also look into I'd how its predecessor and successor are named, to try and create some consistency. — trlkly 18:09, 29 April 2021 (UTC)

unless we rename all of the series before it, then I believe it should stay the way it is now for consistency sake. Matthew Smith (talk) 18:43, 29 April 2021 (UTC)

Renaming Intel 80386 to i386 would make sense too: once again, the official name since 1989 is i386, and both i386 and 386 are in common use, but 80386 isn't. --Crash48 (talk) 05:38, 30 April 2021 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Too late now, but other processors have the manufacturer name prepended - Motorola 6800, Zilog Z80. "Consistency" is never the first word to apply to Wikipedia.--Wtshymanski (talk)

Gonna just criticize this move -- it made the naming wildly inconsistent between articles. Probably better to open another discussion about moving article back or fixing many other articles. Sleeps-Darkly (talk) 21:48, 7 August 2021 (UTC)

Unable to Find Source for Change

Looking at [change], I cannot find any reference to this book online except for this wikipedia article and a forum post. I started looking into this because I didn't understand what "This" was in text: "This was under development on this process". Should we remove this text? It adds information about the name P3.

Vermiceli (talk) 15:50, 16 March 2022 (UTC)

If you join at www.cpu-world.com as a member, you can read the scanned article there. Rjluna2 (talk) 20:32, 12 September 2022 (UTC)

Thank you for that information. I was able to see the soruce. I was confused because I thought it was a book. I've updated the reference to use the cite magazine template and added additional information like editor and subtitle (A Well-Bred Classic The 80386). Let me know if I missed anything. Vermiceli (talk) 03:33, 20 November 2022 (UTC)

You are welcome, Vermiceli. Rjluna2 (talk) 20:11, 5 December 2022 (UTC)

India Education Program course assignment

This article was the subject of an educational assignment at Department of Electronics and Telecommunication, College of Engineering, Pune, India supported by Wikipedia Ambassadors through the India Education Program during the 2011 Q3 term. Further details are available on the course page.

The above message was substituted from {{IEP assignment}} by PrimeBOT (talk) on 20:13, 1 February 2023 (UTC)

Seriously outdated or irrelevant comment on newer designs being thousands of times faster than the original 8086

The current text states that "Over the years, successively newer implementations of the same architecture have become several hundreds of times faster than the original 80386 (and thousands of times faster than the 8086)." My fairly slow and old CPU is several hundreds of thousands times faster than the original 8086, if we're only looking at one core (of which it has multiple). This statement is so outdated it could be considered misleading. 89.239.195.102 (talk) 14:08, 31 August 2023 (UTC)

It would probably be better to say that new ones were many times faster, without giving figures. Bubba73 ^{You talkin' to me?} 14:41, 31 August 2023 (UTC)

That would certainly be an improvement. I'm not objecting to there being a mentioning that things have improved massively, it's just that the scale of improvement is seriously being understated with the current phrasing. Not mentioning the scale at all is much better than mentioning a scale that is several orders of magnitude below what is currently true. 89.239.195.102 (talk) 14:57, 31 August 2023 (UTC)