Earlier quoted context omitted.
Vortex86 is probably the closest thing to what you are looking for.
Any idea when Pixel86 is going to be available again or how/where to get an ITX-Llama system?
Pre-orders:
486Tang – 486 on a credit-card-sized FPGA board
41–50 of 60 posts
Re: 486Tang – 486 on a credit-card-sized FPGA board
#42I miss Intel's Quark chips. Tiny, cheap, and Pentium enough.
Those were actually a 486 microarchitecture with some Pentium instructions added. If you look at the documentation for them, it's obvious that they copy-pasted the 486's and search-and-replaced.
Re: 486Tang – 486 on a credit-card-sized FPGA board
#43Earlier quoted context omitted.
Define "486-compatible." As far as I know even intel's newest cpus can run 486 era 16-bit stuff in hardware. But, a plain answer: Via Eden boards. still use north/southbridge architecture, and are from the mid 2000's. It's just modern Windows/Linux that have discontinued the ability. Or, perhaps you have 16/32 and 32/64 and are unable to do 16bit on 64bit machines- which still boils down to "operating system." By far…
In Windows, once you're in long mode, there's no 16-bit available to you. You can instead take the DOSBox or other VM route. Linux isn't really relevant given the time frame.
I left it open as to if it was a hardware or OS level item that prevents 16bit. Because I don't know, and don't care to dig that rabbit hole.
Also- DOSBox is an emulator vs VMs are hardware, no? I suspect A VM won't fix the "no-op loop for timing" issue- with modern processors' lowest clock being 600-800Mhz before it gets C6/C7'd, 30 years of IPC improvement, and the possibility of the CPU itself optimizing such loops (I'm unsure for various reasons): I expect the UX of "just limit how many scheduler slices it gets" to be nasty.
Re: 486Tang – 486 on a credit-card-sized FPGA board
#44486? If it has VLB, it can play DOOM well!
Indeed! I have a 486 DX4-100 that is my favorite DOOM system. It has an S3 805 VLB card currently, fast enough. Do you have a favorite VLB card for the 486 or DOOM?
This is my favorite build to run DOOM: https://fabiensanglard.net/2168/epilogue/
Re: 486Tang – 486 on a credit-card-sized FPGA board
#45Earlier quoted context omitted.
It does, yes. But the DDR RAM available on the target board is DDR3 which is actually quite inconvenient for retro projects for a number of reasons. Quite apart from the increased complexity, the most important difference is that there's a minimum speed as well as a maximum speed for modern DDR RAM, which means there's usually quite a narrow window of achievable clock rates when getting an FPGA to talk to DDR3. I sus…
Yes, for exactly the reason. SDRAM is much easier to work with in retro computing than DDR.
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Re: 486Tang – 486 on a credit-card-sized FPGA board
#46Out of curiosity, how much of the 138K LUTs (as well as other resources like BRAM) are in use here? I wonder if there's much room to add fancy peripherals, or perhaps "growing" the CPU to achieve better IPC.
It currently uses 44% of the LUTs and 59% of the BRAMs (out of 340 × 2 KB blocks). The chip itself is fairly large and inexpensive, though performance leans toward the lower side.
Re: 486Tang – 486 on a credit-card-sized FPGA board
#47Silly question. Are there any 486-compatible small CPUs that could be embedded into a project instead of using an FPGA? Given that AMD, Intel and others have the ability to make 486-compatible processors currently, I would have thought you could just buy a CPU or SoC to run 486 code.
There is a branch of Via (?) in china making enhanced 486 system on a chip "586" systems. I'm on mobile so I don't have the name handy but I'm still hopeful these get cheap enough to enter the hobby space more.
Re: 486Tang – 486 on a credit-card-sized FPGA board
#48Earlier quoted context omitted.
No, the Quarks did not have the f00f bug, that would have been funny though.
Didn't they have issues with `LOCK CMPXCHG`(not the 8B)? This is out of my depth and I am not sure, but it sounds similar to the f00f bug. 1: https://en.wikipedia.org/wiki/Intel_Quark#Segfault_bug
Yes, they did have the bug with the lock prefix. IOT people at Microsoft got NT booting on the Quark and we ran into that problem. I wound up writing a small tool to patch out all the lock prefixes.
Re: 486Tang – 486 on a credit-card-sized FPGA board
#49I would love to see ancient tech fabbed out on modern processes. What's the smallest SOC you could design to run DOOM? What power envelope would that consume (exclusing display/speakers/etc.) At that size and (optimized) transistor count, what speeds could we realistically achieve? What would a massively-multicore (gpu-style with multi-hundreds or more of cores) one of these run like? Every time I see a project like…
> I would love to see ancient tech fabbed out on modern processes.
> What's the smallest SOC you could design to run DOOM?
Depending on your definition of "modern", more than you think has been done. Intel's Quark were basically 486/Pentium hybrids but fabbed on a fairly modern (at the time) process. While Quark is no longer available as a standalone product, a derivative is part of every modern Intel processor in the form of the Intel ME system co-processor, and it's likely that a number of other Intel products (network cards, QAT accelerators, the ARC GPUs, etc) use them as system controllers as well (Quark essentially came into existence as a "formalization" of the multiple "micro-x86" implementations inside Intel being used as embedded controllers for various non-CPU products).
> What would a massively-multicore (gpu-style with multi-hundreds or more of cores) one of these run like?
This is close to what the original Xeon Phi was. Essentially 60-ish Pentium cores, with modern SMT and 512-bit vector units added. It worked ... OK? If the software development story had been better (e.g. actual first-class support in GCC) I think they could have been a much bigger success, but the need for ICC back in the ICC-costs-real-money days and initially very expensive hardware certainly held them back. At times I do miss some of their behavior.
Arguably a number of the RISC-V-based "AI accelerators" on the market are basically new spins on the same idea: a bunch of small cores, plus large vector/tensor units.
Re: 486Tang – 486 on a credit-card-sized FPGA board
#50I miss Intel's Quark chips. Tiny, cheap, and Pentium enough.
I found 10 Intel Galileo dev kits, new in box, left at our local recycling center on the "Free: Take Me Home" shelf.
And just today, I received the Intel Edison dev kit that I'd purchased on eBay.
The Galileo is a Quark X1000 SoC, two P54C cores. In-order, original 32-bit Pentium.
https://en.m.wikipedia.org/wiki/Intel_Galileo
.
The Edison is a modern System On Module about the size of an SD card but about 3x the thickness of one. It's far more capable: dual 64-bit Silvermont Atom cores, Super scalar out of order. And an additional Quark core as a system monitor, running an independent RTOS. There's also 4GB eMMC, 1GB RAM, WiFi, and Bluetooth on the module. Its quite a remarkable curiosity.
Ten years ago, Intel tried to catch up to ARM in tablets and smartphones, but it was already too late, and this entire segment of Intel was cancelled within a year or two.
https://en.m.wikipedia.org/wiki/Intel_Edison
Next up is building more recent Linux images for these via the Yocto Project and the now cancelled Intel Board Support Packages (BSP).
If you like low power tiny systems, there's a strange amount of fun to be had.