Intel 80386, a Revolutionary CPU • Hacker News Board

Re: Intel 80386, a Revolutionary CPU

#91

Post by dboreham » Mon, Nov 06, 2023, 7:21 AM UTC

hakfoo wrote: post #40

FirmwareBurner wrote: post #36

Earlier quoted context omitted.

You're wrong about Microsoft here. They too have loads of experience developing their SW for multiple architectures, even moreso than Apple. Windows NT shipped on about 7 or so architectures including PowerPC for the Xbox360. And they also have experience with emulation, that's how they got Xbox 360 emulation on the newer X86 models. Just read their papers on arch emulation. What they don't have and Apple has is 10+…

The problem isn't even building NT for ARM/RISC-V/SH-4 or whatever, it's being able to reproduce enough of the surrounding universe that Windows on x86-64 has. Apple has more leverage over devs; they can say "No more x86-64 in N years" and the developers basically have to move to ARM or abandon MacOS. This bootstraps the market; people who want MacOS have to suck it in and buy ARM because it's the only new hardware w…

I've been using an ARM Windows machine as a daily driver (when I'm traveling) for a year. I do that because it has much better battery life than any similar Intel machine, and it has integrated 4G.

Re: Intel 80386, a Revolutionary CPU

#92

Post by pjmlp » Mon, Nov 06, 2023, 7:22 AM UTC

FirmwareBurner wrote: post #36

mschuster91 wrote: post #27

Earlier quoted context omitted.

Yeah but that was only made possible by Apple's unique circumstances: their close control over the entire tech stack, their experience with architecture transitions (PPC->x86-32->x86-64->ARM) and the required tooling (Rosetta, fat binaries, compilers), their relatively small market size, their expertise in developing with/for ARM from iOS, and enough cash in hand to buy out the entire fab capacity of TSMC. In the Win…

You're wrong about Microsoft here. They too have loads of experience developing their SW for multiple architectures, even moreso than Apple. Windows NT shipped on about 7 or so architectures including PowerPC for the Xbox360. And they also have experience with emulation, that's how they got Xbox 360 emulation on the newer X86 models. Just read their papers on arch emulation. What they don't have and Apple has is 10+…

That is not the issue, rather convincing the Windows developer community to actually care about ARM.

Traditionally Microsoft isn't like the others (Apple/Google), "take this or go away", which is why they became so big for enterprises in first place.

Re: Intel 80386, a Revolutionary CPU

#93

Post by jacquesm » Mon, Nov 06, 2023, 7:22 AM UTC

zozbot234 wrote: post #71

johnklos wrote: post #44

I think the 80386's final design benefitted tremendously from the Motorola 68000, then the m68020. Had Motorola not released a proper 32 bit CPU without compromises, it could be argued that Intel would've had yet another stop-gap after the 80286, which itself wasn't intended to be a proper successor to the 8086/8088. As it is, the 80386 came with a number of compromises. For instance, there was no cache at all beyond…

> There were no atomic instructions (/LOCK wasn't useful for this), which is why many modern OSes support the 80486 but not the 80386. Does the lack of atomics really matter, given that there was (AIUI) no SMP on the 386? You can always disable interrupts to make your operation 'atomic' in a uniprocessor context.

Disabling interrupts is a privileged operation (you need IOPL for the ability to execute the cli or sti instructions). Atomics can work even outside of privileged code.

Otherwise you could from any user program disable interrupts and give the operating system no chance to take back control. Xadd, cmpxchg, bts, btr and btc are all prefixable with lock to make them atomic.

Re: Intel 80386, a Revolutionary CPU

#94

Post by dboreham » Mon, Nov 06, 2023, 7:22 AM UTC

mschuster91 wrote: post #38

FirmwareBurner wrote: post #36

Earlier quoted context omitted.

You're wrong about Microsoft here. They too have loads of experience developing their SW for multiple architectures, even moreso than Apple. Windows NT shipped on about 7 or so architectures including PowerPC for the Xbox360. And they also have experience with emulation, that's how they got Xbox 360 emulation on the newer X86 models. Just read their papers on arch emulation. What they don't have and Apple has is 10+…

> Windows NT shipped on about 7 or so architectures including PowerPC for the Xbox360. And they also have experience with emulation, that's how they got Xbox 360 emulation on the newer X86 models. The entire NT stuff has gone down the drain. The last non-x86 platforms were dropped around 2000 [1] until ARM entered the picture in 2012, but the latter was mostly used for Windows Phone for many years which itself got di…

Cutler is still there :)

Re: Intel 80386, a Revolutionary CPU

#95

Post by nezirus » Mon, Nov 06, 2023, 7:24 AM UTC

StillBored wrote: post #66

I really wish people would stop applying the "flat 32-bit" revisionist history to the 386. That wasn't its obvious target, but rather picking up the important "capability" arch features which were seen as the future before unix/c/risc/single supervisor/ideas destroyed the previous 30 years of mainframe/minicomputer OS research in things like security. So, what this article fails to really clarify is that the segment…

It been long since I have stopped following grsecurity, but I would not be surprised if segment registers are still used (e.g. Pax UDEREF)

https://forums.grsecurity.net/viewtopic.php?f=7&t=3046

https://pax.grsecurity.net/docs/PaXTeam-H2HC12-PaX-kernel-se...

Re: Intel 80386, a Revolutionary CPU

#96

Post by pjmlp » Mon, Nov 06, 2023, 7:26 AM UTC

ack_complete wrote: post #62

FirmwareBurner wrote: post #36

Earlier quoted context omitted.

You're wrong about Microsoft here. They too have loads of experience developing their SW for multiple architectures, even moreso than Apple. Windows NT shipped on about 7 or so architectures including PowerPC for the Xbox360. And they also have experience with emulation, that's how they got Xbox 360 emulation on the newer X86 models. Just read their papers on arch emulation. What they don't have and Apple has is 10+…

They do have lots of experience porting Windows to multiple platforms. They don't have very good experience managing the user experience of Windows transitioning between platforms. I was one of the early adopters of Windows on ARM, the Windows 10 native port to ARM64 (ARMv8). At release, practically the only native development tool was WinDbg -- neither Visual Studio nor Windows Performance Analyzer had been ported.…

Are you sure regarding ARM64EC? I doubt that they are dropping it any time soon, specially when they just announced the Arm Advisory Service.

Re: Intel 80386, a Revolutionary CPU

#97

Post by pjmlp » Mon, Nov 06, 2023, 7:34 AM UTC

dboreham wrote: post #94

mschuster91 wrote: post #38

Earlier quoted context omitted.

> Windows NT shipped on about 7 or so architectures including PowerPC for the Xbox360. And they also have experience with emulation, that's how they got Xbox 360 emulation on the newer X86 models. The entire NT stuff has gone down the drain. The last non-x86 platforms were dropped around 2000 [1] until ARM entered the picture in 2012, but the latter was mostly used for Windows Phone for many years which itself got di…

Cutler is still there :)

As per his last interview, nowadays busy porting GNU/Linux into XBox running on Azure, for AI workloads when they are idle.

Somehow there is a certain irony on that.

Re: Intel 80386, a Revolutionary CPU

#98

Post by mratsim » Mon, Nov 06, 2023, 7:40 AM UTC

userbinator wrote: post #59

cmrdporcupine wrote: post #52

Earlier quoted context omitted.

Imagine they got into making an ARM CPU competitive with Apple's? Or a server chip that is better than Ampera's, and sold at scale? I think they have the expertise and ability to do it.

A dual-mode ARM-x86 core would be an interesting CPU that they certainly have the skill to create. Thanks to the protected mode descriptor model, imagine having ARM64, ARM32, x86-32, and x86-64 code segments all coexisting in the same system, with no emulation nor virtualisation. There wouldn't be any overhead, because all instructions regardless of ISA get translated to uops anyway. They could add a RISC-V front-end…

That sounds like dev and user experience nightmare.

Re: Intel 80386, a Revolutionary CPU

#99

Post by Kwpolska » Mon, Nov 06, 2023, 7:40 AM UTC

mschuster91 wrote: post #38

FirmwareBurner wrote: post #36

Earlier quoted context omitted.

You're wrong about Microsoft here. They too have loads of experience developing their SW for multiple architectures, even moreso than Apple. Windows NT shipped on about 7 or so architectures including PowerPC for the Xbox360. And they also have experience with emulation, that's how they got Xbox 360 emulation on the newer X86 models. Just read their papers on arch emulation. What they don't have and Apple has is 10+…

> Windows NT shipped on about 7 or so architectures including PowerPC for the Xbox360. And they also have experience with emulation, that's how they got Xbox 360 emulation on the newer X86 models. The entire NT stuff has gone down the drain. The last non-x86 platforms were dropped around 2000 [1] until ARM entered the picture in 2012, but the latter was mostly used for Windows Phone for many years which itself got di…

Windows 2000 shipped with x86 support only. But just one year later, Windows XP had an Itanic port at launch.

Re: Intel 80386, a Revolutionary CPU

#100

Post by jacquesm » Mon, Nov 06, 2023, 7:43 AM UTC

Gibbon1 wrote: post #79

Aloha wrote: post #73

Earlier quoted context omitted.

The IBM PC had an advantage in that most of the support parts were IIRC largely jellybean 74 series logic - could a PC-PDP have used similar COTS parts? The larger issue with DEC was a strong NIH trend (almost as strong as IBM), I dont know if they could have bucked that trend to successfully launch a market winning PC. It probably would have looked like the DEC Professional, which I think looks like market failure.…

I read an essay by a guy that worked on project to produce a DEC minicomputer using ECL logic. And there was yet another group working on the DEC Alpha. At the time the main group was using most of the companies resources betting the company on dethroning IBM in the main frame arena. And was trying to stab the Alpha and Minicomputer group in the back. So probably not. Suspect IBM's skunk work project was done as a he…

Between x86 and the Alpha I much preferred the Alpha. Unfortunately it was wickedly expensive and it was hard to get. But for 64 bit work it was immediately usable and rock solid. It also beat Intel/AMD by about a decade to the market and I'm still kind of surprised that DEC managed to squander that lead.