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86Box: Why Not Pentium III?

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Re: 86Box: Why Not Pentium III?

#71

Post by kitsunesoba »

leeter wrote: post #31
spijdar wrote: post #5

Something alluded to, but not really elaborated on, is what the motivation is for emulating progressively newer CPUs, versus virtualizing them. With old hardware, the sort I imagine 86Box is mainly used to emulate (it's how I use it, anyway), old OSes rely on specific behavior of old systems and peripherals that can't be easily virtualized through KVM + QEMU or the like. A mixture of processors being too fast and beh…

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…

This is an avenue I’d like to see more pursuit of, and not just for x86 machines — new PowerPC mac motherboards that can be fitted into standard ATX PC cases and can be powered by unmodded off the shelf PSUs would be huge.

Re: 86Box: Why Not Pentium III?

#72

Post by jbjbjbjb »

leeter wrote: post #31
spijdar wrote: post #5

Something alluded to, but not really elaborated on, is what the motivation is for emulating progressively newer CPUs, versus virtualizing them. With old hardware, the sort I imagine 86Box is mainly used to emulate (it's how I use it, anyway), old OSes rely on specific behavior of old systems and peripherals that can't be easily virtualized through KVM + QEMU or the like. A mixture of processors being too fast and beh…

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…

There is a precedent for that with the reproduction Amiga motherboards that came out a couple of years ago. Those were actually just pcbs but something more accessible would be cool.

Re: 86Box: Why Not Pentium III?

#73

Post by frozenport »

phire wrote: post #17
AshamedCaptain wrote: post #9

Earlier quoted context omitted.

The question is which software that requires a Pentium III also requires some CPU timing peculiarity. There have been enough CPU vendors that such software would have been difficult to run even at its era. This is not a videogame console where all hardware was the same, or the early PC world were everything was designed for the Intel 8086 timings as on the IBM PC. This is the modern PC world. Which exact CPU model wo…

I'm of the belief that hardware is not truly preserved until you have a fully-accurate emulation of it. You are correctly that software doesn't require fully accurate timings. Just accurate enough to bypass any timing bugs and replicate the experience. Especially outside of the console space. If your only goal is running all known software, then you can get away with some massive accuracy bugs. But there is more to h…

>> I'm of the belief that hardware is not truly preserved until you have a fully-accurate emulation of it.

BTW Intel has this internally

Re: 86Box: Why Not Pentium III?

#74

Post by celegans25 »

anthk wrote: post #61
mschuster91 wrote: post #52

Earlier quoted context omitted.

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…

The most powerful x86 CPU emulated under an FPGA it's a high end 486 with ao486. Far from a Pentium MMX.

Logic Gate != Transistor and FPGA LUT != Logic Gate

FPGA LUTs are quite sophisticated, the LUTs in both Xilinx and Intel's latest offerings are able to implement an arbitrary boolean logic function with up to 6 inputs and 1 output. The FPGA also comes packed with other specialized hardware such as on chip memory and multipliers so you do not need to burn logic to use those things. You very likely could fit a Pentium III on a moderately large FPGA.

The real challenge would be matching the clock speed of the original processor. Even 400MHz of the first pentium IIIs on the market might be difficult, getting near 1GHz is likely impossible.

Re: 86Box: Why Not Pentium III?

#75

Post by The_rationalist »

rnd0 wrote: post #70
The_rationalist wrote: post #57

Earlier quoted context omitted.

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

>Because this is where the human resources should be allocated, That's unwarranted hubris. It's not your call to tell developers where to direct their volunteer efforts.

Should does not equal must. Wanting a better world with less suffering and more joy is not the same thing as imposing this world by force. A thought that should have occured to you.

Re: 86Box: Why Not Pentium III?

#76

Post by rnd0 »

The_rationalist wrote: post #75
rnd0 wrote: post #70

Earlier quoted context omitted.

>Because this is where the human resources should be allocated, That's unwarranted hubris. It's not your call to tell developers where to direct their volunteer efforts.

Should does not equal must. Wanting a better world with less suffering and more joy is not the same thing as imposing this world by force. A thought that should have occured to you.

It is still not your place to say what people's ideals should be, or what efforts that they should persue.

Re: 86Box: Why Not Pentium III?

#77

Post by crest »

kitsunesoba wrote: post #71
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…

This is an avenue I’d like to see more pursuit of, and not just for x86 machines — new PowerPC mac motherboards that can be fitted into standard ATX PC cases and can be powered by unmodded off the shelf PSUs would be huge.

Where will you get your supply of custom chipsets? Do you want to reverse engineer Apple's already badly documented chipsets and reimplement them on fast enough FPGAs maybe even support more modern RAMs or improved off-chip caches? It would be nice to have a mATX NewWorld Mac you can maintain for playing old MacOS games, but the farther you go into the G4 (or even worse G5) era the more advanced GPUs you would have to reimplement as well. The PPC6xx era 2D on-board graphics may be in reach of such a project, but I can't see anyone without Nvidias active support releasing a Quadro FX 4500 compatible GPU clone.

Re: 86Box: Why Not Pentium III?

#78

Post by dehrmann »

leeter wrote: post #31
spijdar wrote: post #5

Something alluded to, but not really elaborated on, is what the motivation is for emulating progressively newer CPUs, versus virtualizing them. With old hardware, the sort I imagine 86Box is mainly used to emulate (it's how I use it, anyway), old OSes rely on specific behavior of old systems and peripherals that can't be easily virtualized through KVM + QEMU or the like. A mixture of processors being too fast and beh…

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…

Maybe you could do a hardware version of that the emulation community does and say "this FPGA should act like a chipset X, here's how to program it, but don't ask us for the blob."

Re: 86Box: Why Not Pentium III?

#79

Post by kitsunesoba »

crest wrote: post #77
kitsunesoba wrote: post #71

Earlier quoted context omitted.

This is an avenue I’d like to see more pursuit of, and not just for x86 machines — new PowerPC mac motherboards that can be fitted into standard ATX PC cases and can be powered by unmodded off the shelf PSUs would be huge.

Where will you get your supply of custom chipsets? Do you want to reverse engineer Apple's already badly documented chipsets and reimplement them on fast enough FPGAs maybe even support more modern RAMs or improved off-chip caches? It would be nice to have a mATX NewWorld Mac you can maintain for playing old MacOS games, but the farther you go into the G4 (or even worse G5) era the more advanced GPUs you would have t…

Chipsets indeed prove a challenge, but it’s not insurmountable. QEMU’s emulation of a G3 tower is a decent example of this.

There’s decent availability of PCI and AGP GPUs supported by OS 9 and early OS X, especially if you include PC variants that can be flashed to work with Mac OS, so I wouldn’t worry about video too much in the short term… just make sure the motherboard has a PCI or AGP slot.

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