x86 architecture concepts

Yes. If it looks like x86, walks like x86 and quacks like x86 - it is x86 :) All competitors' (AMD etc.) processors can execute the binary code for Intel's x86. *How* they do it internally -- might be completely different.

No, IMHO.

Vadim

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Vadim Borshchev
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Not only could they --- they did. It's called the Pentium-M, but for some silly marketing reasons they pretent it's for laptops only (-->

that obnoxious "Centrino" campaign).

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Hans-Bernhard Broeker

The "silly reason" is so that they can charge a higher price for it. :)

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Grant Edwards                   grante             Yow!  I selected E5... but
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Grant Edwards

"Mouarf" wrote

No. Usenet is not for doing your homework (schoolwork) for you!

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Nicholas O. Lindan, Cleveland, Ohio
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Nicholas O. Lindan

please stop with homework, I'm not a student....

"Nicholas O. Lindan" a écrit dans le message de news: zS5Td.5309$ snipped-for-privacy@newsread2.news.atl.earthlink.net...

Reply to
Mouarf

"Mouarf" wrote

Funny, most posters think you are. You certainly behave like one.

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Nicholas O. Lindan, Cleveland, Ohio
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Nicholas O. Lindan

When I will need nothing, I'll call for your help....

"Nicholas O. Lindan" a écrit dans le message de news: SP6Td.5380$ snipped-for-privacy@newsread2.news.atl.earthlink.net...

Reply to
Mouarf

Not for a long time but as far as I remember they only told , in rough, that they use less transistors and a different cache memory for data and instructions, this does not explain why the final emulation is fast. I did not see how many clock cycles (or how many Transmetta instructions) are necessary to performe an emulated x86 instruction.

Regarding the power consumption, Intel faces every day with power dissipation (90W over few square centimeters), they certainly tend to reduce the power consumption by reducing the number of transistors (at least) and improving the efficiency of an operation execution (make it not so complex), I'm surprised that other companies (x86 competitors) are able to do that much easier than Intel.

In brief, my first question on this topic was more a vocabulary question (and certainly badly exposed considering the reaction of other readers) because "x86" word is used almost every day but only few people know what this exactly refers to. That's why I also tried to understand what the correct definition of an "architecture" is (some colleagues told me that "architecture" only refers to the memory organisation around the µC core, others say that it depends on instruction set, others even senior have no clear idea....).

Many thanks to Grant and Vadim to have shared their knowledge which is not trivial to find on the www.

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Mouarf

Please do NOT toppost. It is rude and extremely annoying.

and a set of registers. The register set has expanded since the

8086, but has not changed the fundamentals. The registers tend to be special purpose, such as source and destination index (si and di), counter (cx), accumulator (ax), block pointer (bp), rather than general registers. AMD and Intel have much different implemenations of the same basic architecture. (Although AMD got into the business as a licensed second source for the Intel CPUs, but that ran out and they compete on their own now.)
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CBFalconer

... snip ...

No, it was a decision that produced an instant set of applications ported from CP/M via a fairly simple source code translation mechanism, and thus made the IBM PC popular back in the early '80s. Without that it would have competed on equal grounds with such things as the Motorola 68000, the National IMPS, the Zilog Z8000, etc. All but the 68000 are now gone, and even that is on its last legs.

Without that decision we wouldn't have the Microsoft/Gates monopoly sucking at us today.

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Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
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CBFalconer

According to my own, dim, memory, history says that there were indeed several licencing-related restrictions and patent portfolios involved. AMD was granted licences back in the day (8086 and 8088, or maybe even

8085-vintage) when "second sources" had to be available before anyone would buy a part. I don't think that they were the only ones to get licences for that reason. IBM got licences in order to build (I think) the 386sx or some such. Transmeta and the originators of the Geode (wasn't always National Semiconductor: they bought it from ?Cirix?) get to build their chips because they use IBM's fab facilities, and therefore come under IBM's licence agreements. Or so I've read.

Cheers,

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Andrew
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Andrew Reilly

"CBFalconer" wrote

My prejudices come from a design implemented first in 68000 and then re-designed in 8086. As a result my conclusion was the 8086 architecture, though somewhat weird, turned out to be, oh let us say, "useful." The 68000 was left with most of its registers unused.

The tragedy of the PC is that IBM didn't take Intel's iRMX operating system and PLM/86 and instead went to a scheming little college drop-out who took them blind and saddled them with kinder spiel technology.

iRMX was multi-user, networked and password secure from the get-go. PLM/86 and the 8086 were designed to go together -- like C only makes sense on a PDP-11 (Oh, I am going to hear howls for that one).

PLM did have it's problems: it's ability to handle arrays was ROTFL - the _language_ addressed data only as far as the 8086 could address data in one instruction - an array of structures with arrays as members of the structures. 3-d arrays, never heard of them ...

And iRMX was slow, really slow.

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Nicholas O. Lindan, Cleveland, Ohio
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Nicholas O. Lindan

I think the silly reason is so they won't kill off their meat and potato P4 chips. Recent Pentium M benchmarks are showing that the high end Pentium M (2.1 GHz) performs about as well as a 3.2 GHz P4 for 20% of the power. In response, Intel charges more than 2x as much for the low power part.

Kelly

Reply to
Kelly Hall

"CBFalconer" wrote

It only sucks at you if you let it. Alternatives exist for just about any Microsoft product. Many of the alternatives are pretty good. Many suck worse than the Windows version.

"Labored", perhaps, but "suffered"? You want to talk suffer> The tragedy of the PC is that IBM didn't take Intel's

Seems to me that IBM and Microsoft both did quite well based on that business decision. Could they have made better (more elegant) technical decisions? Certainly. But it's not clear that they would have made more money with more elegant technology.

Alternatives have always existed, since IBM offered CPM-86 and UCSD P-System in the catalog along with PC/MS-DOS. UCSD was non-starter for business folks, and DRI priced themselves out of the market. MS-DOS was good enough for Visicalc and WordStar, and the rest is history.

Technical elegance and good business intersect too rarely.

Kelly

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Kelly Hall

I believe there were copyrights asserted on the instruction mnemnonics. However they were licensed to AMD early on, along with the dies etc. to build the earlier x86s. That die license (for 2nd sourceing) was pulled about the time of the 286 (or was it 386?)). However I believe that process allowed the use of the mnemnonics forever.

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CBFalconer

It means different things to different people. To software people it means the instruction set and addressing range. To hardware people, it may include things like the bus structure.

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Grant Edwards                   grante             Yow!  Will this
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Grant Edwards

I'm not buying that arguement. From what I knew, most CP/M applications were just re-written by hand. I never met anybody who had used the mythical 8080 -> 8086 assembly language translator. Since there was a CP/M for the 68K, I don't see how the pseudo-backwards comopatibility with the 8086 made much difference.

That's for sure.

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Grant Edwards                   grante             Yow!  Look DEEP into the
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Grant Edwards

It was pulled when pentium (586) came out. AMD made 8086, 286, 386, 486 (intel design). When intel made pentium, AMD could not catch up, so AMD made those 100MHz and 133MHz 486's. AMD's own design, 586, does not work fast enough to compete with Intel Pentium. So AMD had to buy Nexgen (founded by former employees from Intel), and made the new Nexgen processor

686. Thats when AMD started to catch up.

vax, 9000

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vax, 9000

I agree with you with two arms and two legs up. The compatibility desicion Intel made was brilliant. Just look at i432, i860 and IA64. i432 died before it released. i860 was not successful at all, found its place in embedded devices, or intel super computers only. IA64 almost killed Intel. On the other hand, AMD got a new breath after it designed AMD64, the latest family member of X86.

Think what would have happened if Zilog designed the Z180 other than Z8000 in 1979, or Motorola designed an extension of 6800 otherthan the 68000 in

1979... They would have been able to compete better.

vax, 9000

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vax, 9000

In short It means the processor is descended for the 8088 in the original IBM PC. A poor architecture (the MMU was strange). Each new member could run the code of the one before it. It evolved as a desktop processor that runs Windows. It is not power efficient, because it did not have to be ( other than heat dissipation). It is a CISC because that what the 8088 was. Many newer CPUs are RISC because that was in style when they where created. If the where designed to be portable they use less power, Or they would not get used. ARM has built its niche. The bigger X86s have their own.

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Neil Kurzman

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