Show HN: Homemade 32-bit CPU and OS (2015) [video]

https://www.youtube.com/watch?v=OQKCLf32TB8

by tomsm • 10 years ago

253 37 10 years ago

dang2• 10 years ago

Since it looks like the author posted this, we've added "Show HN" to the title. Normally that requires something people can try out, but when you're making something on an FPGA * that's hard to do, so a demo is fine, as long as it works.

* I originally said "making your own hardware" but that caused confusion. Sorry!

ebbv• 10 years ago

He didn't make his own hardware though? It's a software based CPU. Actually manufacturing a CPU at home would require you to crash at a foundry. Or y'know build a really, really slow one out of parts that you could actually use in your home.

I think this is really cool but all he did was use a cool product for exactly what it is intended for.

The video seems to be deliberately non-obvious that this is all software based. If you're gonna post it for public consumption you should be more up front, I think, or some people are probably going to assume you actually did manufacture your own CPU From the title.

dang2• 10 years ago

Ok we'll change the title back to what it was originally. Sorry for the distraction.

Edit: actually this is still pretty cool work and it isn't the creator's fault that I oversold it, so I've put "Show HN" back and edited my root comment above. Let's discuss the video now!

chc4• 10 years ago

There are plenty of hand-built CPU projects built by enthusiasts, made out of wire-wrapped integrated circuits[0]. There was even a Zuse homage I saw that was built entirely out of magnetic relays[1]. It's...insane, tbh.

0: http://www.homebrewcpu.com/ 1: http://nablaman.com/relay/

peterkelly• 10 years ago

He says at the beginning that the CPU is written VHDL and it's running on an FPGA.

tomsm2• 10 years ago

I've built custom HW for the FPGA based SoC now too. https://youtu.be/ZDELr2QHxec?t=6m56s

coin• 10 years ago

I was expecting to see a wire wrap type CPU, but instead it's just an FPGA

sklogic2• 10 years ago

This semantic argument that "is FPGA a real hardware" is pointless. All the same arguments that the "software" side can produce are also applicable for, say, a circuit built on a breadboard. Is this circuit not a "real circuit", but a "software" for some weird reason? And if not, stop calling FPGA bitfiles a "software".

etatoby• 10 years ago

This is part 1/2 of a brief description/demo of a CPU I have designed in my spare time, and an OS which I have written for it.

He claims to have designed his own CPU, not physically built it.

VHDL/Verilog is the correct way to do it and an FPGA is the best way to actually run (as opposed to simulate) the hardware design.

I don't see anything remotely misleading here.

danellis2• 10 years ago

It isn't all software based. It's running on an FPGA. He made that perfectly clear at the beginning.

db1• 10 years ago

This reminds me of http://nand2tetris.org/ (and the accompanying Coursera course). It's a fantastic course to learn about computing from first principles.

The course starts off with just a few logic gates and how you can combine these to make more complicated circuits. These are in turn combined to reach higher levels of abstraction, until you finally have a 16bit computer, with 16K of ram. It's a really cool course that helped me flesh out my understanding of what's going in my computer.

talnet• 10 years ago

Hey thanks for the course pop up.

nul_byte• 10 years ago

Quick question if I may. I have a very keen interest in trying this course...is what you build (hack) using actual physical circuits / components? Or do you run it all in simulation?

projektfu• 10 years ago

It's all simulation using a simplified HDL.

d0mine• 10 years ago

You might also like the book CODE: The Hidden Language of Computer Hardware and Software http://www.charlespetzold.com/code/index.html

It starts with sending signals using flashlights and follows the evolution of computers from the ground up (mostly hardware).

max_• 10 years ago

This is a realy great submission... thanx!!

Zardoz84• 10 years ago

I don't know if I should post on HW, my 32-bit CPU that only exists as software emulator, plus a basic firmware that consists on a basic BIOS + machine code monitor that imitates Apple ][ Wozniak's machine code monitor. I ever managed to get a Raspery Pi B to run the emulator.

I try to wrote the CPU as VHDL, but I only did a few pieces (registers storage and a 32 bit ALU), so I can get a real and accurate cycle count for each instructions.

DanBC• 10 years ago

I don't know if I should post on HW

Many people would be really interested to read a submission about that. I think they'd especially be interested to read how you solved any problems you had.

jackhack• 10 years ago

second that. It sounds fascinating.

bpye• 10 years ago

This is really cool, something I've wanted to do but never actually done. The closest I've been is a very simple 8 bit CPU implemented in Verilog ( https://gist.github.com/benpye/07aa8a66e25a7c702766 ), the program in the BRAM I think calculates the 5th number in the fibbonachi series or something, I've forgotten. It works on the ice40 hx8k breakout board if anyone wants to try it, I was using the icestorm toolchain.

danellis2• 10 years ago

I can definitely see some ARM inspiration here, and the guy's English, so I wonder if he grew up with Acorn hardware.

yxlx• 10 years ago

He sounds like he's in his twenties to me. If so, do you think he would have had an Acorn computer? I dunno, could be.

tomsm2• 10 years ago

Hi, yes indeed, our 1st comp. arch. course at uni was based on ARM hence the influence. Unfortunately I did not have an Acorn machine.

cjdrake• 10 years ago

Cool demo. Did the author post the source anywhere? This would be a great reference for do-it-yourself-ers.

Show HN: Homemade 32-bit CPU and OS (2015) [video]

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