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Happy Birthday! X86 Turns 30 Years Old
javipas writes "On June 8th, 1978 Intel introduced its first 16-bit microprocessor, the 8086. Intel used then "the dawn of a new era" slogan, and they probably didn't know how certain they were. Thirty years later we've seen the evolution of PC architectures based on the x86 instruction set that has been the core of Intel, AMD or VIA processors. Legendary chips such as Intel 80386, 80486, Pentium and AMD Athlon have a great debt to that original processor, and as recently was pointed out on Slashdot, x86 evolution still leads the revolution. Happy birthday and long live x86."
Motorola always had better product, just worse marketing.. If IBM had chosen the 68K in their instruments machine, instead of the 8086/8085 from the Displaywriters, we would have saved ourselves from 3 decades of segmented address space, half a dozen memory models and non-orthogonal cpu architecture.
The other big success is their constant work on making the entire system architecture better, and basically giving that work to the industry for free.
While I'm sure thats how the script was repeated in Intel, suggesting great generosity ("And we give it away for free!"), what choice did they really have? IBM's whole Micro Channel Architecture fiasco showed what licensing did to adoption of new advances in system architecture and integration.
Before the 8086 was released, I knew a V.P. of Technology who was extremely excited about it. Every time I saw him, he would tell me the date of release, and how much he was waiting for that date.
On that day, he was very sad. Intel made some horrible design decisions. We've had to live with them every since. Starting with the fact that assembly language programming for the X86 architecture is really annoying.
What may have been a limitation some time ago might start to be an advantage. I'm under the impression that there's already more than enough transistors to go around per processor, and there's nothing *special* that can be done with them, so it's just cramming more cores and more cache into a single chip. So parsing, splitting and parallelizing complex instructions at the processor may not be very costly after all. OTOH I bet it does reduce the memory bandwidth needed, which definitely is an advantage.
My theory is that Itanium was secretly never created to replace x86; rather, it was designed to kill of all competitors to x86. Think about it: Intel managed to convince the vendors of several architectures (PA-RISC, Alpha come to mind) that IA-64 was the future. They proceeded to jump on Itanium and abandon the others. When Itanium failed, those companies (along with the hope of reviving the other arch's) went with it, or jumped to x86 to stay in business. Ta-da! x86 is alone and dominant in the very places IA-64 was designed for. Intel 1, CPU tech 0.
Happy birthday and long live, x86.
Oh my god, no ! Die already ! The design is bad, the instruction set is dumb, too much legacy stuff from 1978 still around and making CPUs costly, too complex and slow. Anyone who's written assembler code for x86 and other 32-bit CPUs will surely agree that the x86 is just ugly.
Even Intel didn't want it to live that long. The 8086 was hack, a beefed up 8085 (8-bit, a better 8080) and they wanted to replace it with a better design, but iAPX 432 turned out to be a desaster.
The attempts to improve the design with 80286 and 80386 were not very successful... they merely did the same shit to the 8086 that the 8086 already did to the 8085: double the register size, this time adding a prefix "E" instead of the suffix "X". Oh, and they added the protected mode... which is nice, but looks like a hack compared to other processors, IMHO.
And here we are: we still have to live with some of the limitations and ugly things from the hastily hacked together CPU that was the 8086, for example no real general purpose registers: all the "normal" registers (E)AX, (E)BX, etc. pp. are bound to certain jobs at least for some opcodes. No neat stuff like register windows and shit. Oh, I hate the 8086 and that it became successful. The world could be much more beautiful (and faster) without it. But I rant that for over ten years now and I guess I will rant about it on my deathbead.
What about CISC-to-RISC translation?
I do believe that was first done by an x86 CPU, the NexGen Nx586 (the predecessor to the AMD K6...)
What you're really saying is that "if only the chip had been a little more expensive to produce things might have been different." Adding a few little tweaks to devices was a heck of a lot more expensive in the 80s than it is today. The reality is that had Intel done what you asked, the x86 might not have succeeded this long at all.
But would the extra RAM have been affordable to typical users of these programs at that time?
I remember fighting for expensive upgrades from 4 to 8 MB RAM at my workplace back in the early 90's. At that time PCs had already been able to use more than 1 MB for some years. So the problem you are referring to must have been years earlier where an upgrade from 1 to 2MB might probably have been equally expensive.
maybe that will finally be enough to run vista at a decent speed.
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upon the advice of my lawyer, i have no sig at this time
x86 succeeded for exactly one reason - volume. If IBM had chosen the 68K over the x86 we'd be using that today.
Back in the 80's it was a lot cheaper to develop a processor. They were considerably simpler and slower. The reason there were so many processor architectures around back them was that it was feasible for a small team to develop a processor from scratch. It was even possible for a small team to build, out of discrete components, a processor that was (significantly) faster than a fully integrated microprocessor, e.g. the Cray-1.
As the semiconductor processes improved and more, faster, transistors could get squeezed onto a chip, the complexity and the speed of microprocessors increased. Where you're at today is that it takes a billion dollar fab and a huge design team to create a competitive microprocessor. x86 has succeeded because there is such a torrent of money flowing into Intel from x86 sales that it is able to build those fabs and fund those design teams.
PowerPC, for example, was a much smaller effort than Intel back in the mid-90's. PowerPC was able, for a short time, to significantly outperform Intel and remained fairly competitive for quite a while even though the design team was much smaller and the semiconductor process was not as sophisticated as Intel's. The reason for that was that the architecture was much better designed than Intel, making it easier to get more performance for fewer $$. Eventually, however, the huge amount of $$ going into x86 allowed Intel to pull ahead.
The question is whether a processor running its native instruction set would be faster. From what I can tell the native instruction format of a modern x86 is wider than the x86 equivalent. Suppose the uops in the pipeline are 48 bit - a 32 bit constant and a 16 bit instruction. That is quite a bit larger than a typical x86 instruction. Wider instructions take more space in Ram and cache. You don't need to decode them, but the extra time fetching them kills the advantage.
And what is native is very implementation dependent. An AMD chip will have a very different uop format from an Intel one. Actually even between chip generations the uop format might change. Essentially Risc chips tried to make the internal pipeline format the ISA. But in the long run that wasn't good. Original Risc had branch delay slots and later superscalar implementations where branch delays work very differently had to emulate the old behaviour because it was no longer at all native. So if you did this you'd get an advantage for one generation but later generations would be progressively disadvantaged. Or you could keep switching instruction sets. But if most software is distributed as binaries that is impossible.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;