86Box: Why Not Pentium III? • Hacker News Board

Re: 86Box: Why Not Pentium III?

#51

Post by memetomancer » Fri, Apr 08, 2022, 2:32 PM UTC

AshamedCaptain wrote: post #35

phire wrote: post #32

Earlier quoted context omitted.

Accurate timing is most useful when you are retro-programming a video game, or something else real time. How do you know if your game will run at 60 fps if the execution times aren't accurate? > what CPU timing would you even emulate Ideally your emulator would support as many CPU + hardware configurations as possible, at many different speeds, so you can test as many as you want. But just one single accurate hardwar…

> How do you know if your game will run at 60 fps if the execution times aren't accurate? Again, this is not a console. If you rely on a specific Pentium 3's instruction timings to reach 60 fps, your game is not going to reach 60fps _on any other PC_, not even if someone has an identical CPU, since any single other difference in hardware, configuration, or even layout of the filesystem is going to matter much more. Y…

There is a world of difference between your inability to see the appeal/utility of a thing and that thing being actually worthless, as you are so stridently insisting here.

For a mental exercise, just to prove it to yourself, why don't _you_ try examining all the reasons such accurate emulation might be desirable?

The other poster already provided a reasonable motivation - preservation. But since this discussion started, you've only really come out swinging with disparagement. One has to wonder why you are putting so much energy into suppressing and trashing someone's hobby.

Frankly it looks to me like you have some kind of preconceived and inflexible bias, or that you maybe trying to discover the appeal to this effort in a pointlessly adversarial way. Not a great look. If you really want people to think you have a smart, winning argument maybe try to show some understanding of both sides of the coin before floating your attempt at a clever and withering denouncement.

Re: 86Box: Why Not Pentium III?

#52

Post by mschuster91 » Fri, Apr 08, 2022, 2:34 PM UTC

zozbot234 wrote: post #10

Arguably, cycle-accurate emulation should be done with FPGA support anyway. The Pentium III is old enough that there should be no legal obstacle to implementing new compatible hardware.

The problem won't be legal, but scale: the Pentium 3 has ~9.5M transistors [1] - and the world's largest FPGA, at a staggering price point of 55.000 dollars, has only 9M logic gates [2].

Probably you could use an FPGA a bit smaller if you use FPGA-native memory for L1-L3 instead of transistors, but you'll nevertheless need an FPGA that is many orders of magnitude too expensive for a hobbyist niche project. Also, you would need serious quality photographs of the die... which can be done for old and small chips on a budget, but will be really expensive even for something of the Pentium 3 era.

What has always interested me though: how are CPUs and modern GPUs actually developed, given that FPGAs are way, way too small and silicon-making runs extremely expensive?

[1] https://www.computerhistory.org/revolution/story/330

[2] https://hackaday.com/2019/09/24/who-could-possibly-need-an-f...

Re: 86Box: Why Not Pentium III?

#53

Post by Comevius » Fri, Apr 08, 2022, 2:39 PM UTC

dusted wrote: post #29

AshamedCaptain wrote: post #15

Earlier quoted context omitted.

There is SMP P3 emulation. qemu is an emulator, not a virtualizer. There is no cycle-accurate emulation, but again the question is: why would need cycle-accurate emulation to run win2k? It runs just fine on virtualizers, even.

But I don't want virtualization, I want cycle accurate emulation of my p3, actually, I want emulation of the underlying chip so that I can run the original Intel microcode on it. I want my bios chips and all that jazz. I want a ship in a bottle, complete with the seven seas and the world to travel. I want it described in software, so it can be emulated, on whatever the future brings, forever.

Probably no software was ever written specifically for the Pentium 3 (so that it would break on a Pentium 4, or different Pentium 3), so there isn't much reason to emulate it too accurately.

What you are asking is FPGA territory anyway, maybe not even that, the Pentium 3 is too complex to accurately emulate.

Re: 86Box: Why Not Pentium III?

#54

Post by leeter » Fri, Apr 08, 2022, 2:43 PM UTC

sidewndr46 wrote: post #45

leeter wrote: post #31

Earlier quoted context omitted.

I recall awhile back Linus Tech Tips pointed out that the primary failure point for old machines wasn't the CPUs which tend to be piling up cheaply (I can't say how true this is for pre PIII parts) but instead the motherboards. I wonder if in some sense there isn't a market for someone to just make new motherboards instead for this stuff using modern parts. I realize there are some licensing issues after a certain po…

For the Intel chips up to and including the Pentium 4 licensing a chipset would not be an issue. VIA made chipsets back when those products were new. I think there was a lawsuit about it, but VIA prevailed. You could license the chipset from them, then use it with an authentic Intel CPU. https://en.wikipedia.org/wiki/List_of_VIA_chipsets#:~:text=V... . But to your original point: CPUs don't really fail unless abused…

That might even be ideal insofar as the chipset is driver compatible with equivalent from the time. Via wasn't anything special but they were super common and thus decently supported IIRC.

Re: 86Box: Why Not Pentium III?

#55

Post by anthk » Fri, Apr 08, 2022, 2:54 PM UTC

memetomancer wrote: post #51

AshamedCaptain wrote: post #35

Earlier quoted context omitted.

> How do you know if your game will run at 60 fps if the execution times aren't accurate? Again, this is not a console. If you rely on a specific Pentium 3's instruction timings to reach 60 fps, your game is not going to reach 60fps _on any other PC_, not even if someone has an identical CPU, since any single other difference in hardware, configuration, or even layout of the filesystem is going to matter much more. Y…

There is a world of difference between your inability to see the appeal/utility of a thing and that thing being actually worthless, as you are so stridently insisting here. For a mental exercise, just to prove it to yourself, why don't _you_ try examining all the reasons such accurate emulation might be desirable? The other poster already provided a reasonable motivation - preservation. But since this discussion star…

PC games stopped being CPU cycle-bound long ago in mid-late 90's.

The most issues you would have it's for high 486-Pentium I-II era games (specially the multimedia ones) which lots of them were speed bound, but for sure these games will be interpreted by ScummVM one day or another (Macromedia Director engine).

Re: 86Box: Why Not Pentium III?

#56

Post by anthk » Fri, Apr 08, 2022, 2:55 PM UTC

pornel wrote: post #23

AshamedCaptain wrote: post #15

Earlier quoted context omitted.

There is SMP P3 emulation. qemu is an emulator, not a virtualizer. There is no cycle-accurate emulation, but again the question is: why would need cycle-accurate emulation to run win2k? It runs just fine on virtualizers, even.

Perhaps for games with DRM?

Most DRM ridded games were cracked.

Re: 86Box: Why Not Pentium III?

#57

Post by The_rationalist » Fri, Apr 08, 2022, 3:13 PM UTC

Comevius wrote: post #49

The_rationalist wrote: post #37

I don't understand,the yuzu (switch) emulator has excellent performance and correctness. It perfectly emulate a modern ARM cpus at multiple GHz and properly emulate the Tegra Nvidia GPU. Why would emulating x86 be so much harder, especially since you can actually use the host x86 cpu... via hardware hyoervisors e.g. https://github.com/intel/haxm

Yuzu uses Unicorn, which uses QEMU code for functional, but not cycle accurate CPU emulation. Most software these days don't depend on the exact behavior of the hardware, even on Nintendo Switch, and the emulator can also use application-specific patches to make up for the difference. 86Box is not entirely cycle accurate, but much more accurate than QEMU, so no patches are required. gem5 is on the other end of the sp…

Well that makes pcem and x86box very niche then.. What should people actually use for emulating a recent x86 cpu like found on the PS4/PS5/xbox serie x and get good performance? Because this is where the human resources should be allocated, for enabling the support of hundreds of video games including major console exclusives

Re: 86Box: Why Not Pentium III?

#58

Post by AshamedCaptain » Fri, Apr 08, 2022, 3:16 PM UTC

memetomancer wrote: post #51

AshamedCaptain wrote: post #35

Earlier quoted context omitted.

> How do you know if your game will run at 60 fps if the execution times aren't accurate? Again, this is not a console. If you rely on a specific Pentium 3's instruction timings to reach 60 fps, your game is not going to reach 60fps _on any other PC_, not even if someone has an identical CPU, since any single other difference in hardware, configuration, or even layout of the filesystem is going to matter much more. Y…

There is a world of difference between your inability to see the appeal/utility of a thing and that thing being actually worthless, as you are so stridently insisting here. For a mental exercise, just to prove it to yourself, why don't _you_ try examining all the reasons such accurate emulation might be desirable? The other poster already provided a reasonable motivation - preservation. But since this discussion star…

> There is a world of difference between your inability to see the appeal/utility of a thing and that thing being actually worthless, as you are so stridently insisting here.

I am asking a question, and answering "preservation" (which is not really the answer the poster made, since his goal is new development) without giving an actual concrete example of what behavior needs such accurate preservation kind of defeats the purpose of asking the question in the first place.

If the answer is "for the sake of it" that is also fine. But I'm unaware of anything post-P3 that would really require cycle-level emulation, so I ask. Most PC emulators "draw the line" around that era for a reason, even the ones who wouldn't necessarily have performance problems with newer machines (like DosBox).

> But since this discussion started, you've only really come out swinging with disparagement. One has to wonder why you are putting so much energy into suppressing and trashing someone's hobby.

What do you think? Because not only I have the same hobby, my work is also related to this. I am most definitely not interested in thrashing it.

It is also the _main thesis_ of this entire article, so why shouldn't we discuss it?

Re: 86Box: Why Not Pentium III?

#59

Post by nitrogen » Fri, Apr 08, 2022, 3:19 PM UTC

memetomancer wrote: post #51

AshamedCaptain wrote: post #35

Earlier quoted context omitted.

> How do you know if your game will run at 60 fps if the execution times aren't accurate? Again, this is not a console. If you rely on a specific Pentium 3's instruction timings to reach 60 fps, your game is not going to reach 60fps _on any other PC_, not even if someone has an identical CPU, since any single other difference in hardware, configuration, or even layout of the filesystem is going to matter much more. Y…

There is a world of difference between your inability to see the appeal/utility of a thing and that thing being actually worthless, as you are so stridently insisting here. For a mental exercise, just to prove it to yourself, why don't _you_ try examining all the reasons such accurate emulation might be desirable? The other poster already provided a reasonable motivation - preservation. But since this discussion star…

To add an example to your arguments, the C64 and PC/XT demo scenes show what can be done with cycle accurate retrocomputing. Especially 8088mph: https://youtu.be/yHXx3orN35Y

Re: 86Box: Why Not Pentium III?

#60

Post by anthk » Fri, Apr 08, 2022, 3:20 PM UTC

Comevius wrote: post #53

dusted wrote: post #29

Earlier quoted context omitted.

But I don't want virtualization, I want cycle accurate emulation of my p3, actually, I want emulation of the underlying chip so that I can run the original Intel microcode on it. I want my bios chips and all that jazz. I want a ship in a bottle, complete with the seven seas and the world to travel. I want it described in software, so it can be emulated, on whatever the future brings, forever.

Probably no software was ever written specifically for the Pentium 3 (so that it would break on a Pentium 4, or different Pentium 3), so there isn't much reason to emulate it too accurately. What you are asking is FPGA territory anyway, maybe not even that, the Pentium 3 is too complex to accurately emulate.

>Probably no software was ever written specifically for the Pentium 3

The XBOX, but for PC it doesn't has sense unless you want cycle accurate emulation to exploit SSE under an emulated OS such as Windows 98 under Bochs.