Gigatron Hackers

Here's a possible change that might be for the better, and costs no chips: I'm pretty sure that suba is very rarely used in comparison to adda. In some cases it's because we find ourselves wanting to calculate a - b, in cases where we've just calculated b, so that is what we're holding in the accumu...

That should probably be added to the pinned topic

Of course you can just run Marcel's C emulation code, but then you need a decent 1GHz+ architecture to run that at 60Hz. I'd been thinking about this sort of thing (but for other reasons - maybe more to come ;) ), and it seems to me that it should be quite achievable to get realtime performance on ...

My deadline is on Saturday, so if anyone has any feedback on this, I'd appreciate it.

Hi all, I'm going to be proposing a talk on the things I've done with the Gigatron in Python at PyCon UK 2022 in September. I'd be really keen to get your feedback on the proposal. The conference have some guidance on what makes a good proposal here . Title: Alternative History Retrocomputing Abstra...

I think all the points you've made are exactly spot on. What should that instruction be? A 8x8 multiplication? Yes - I think so. Anything else would seem overly specific to an intended application. vCPU has a sixteen bit accumulator, so that seems like the result size it can best handle, and it's ea...

Hi everyone, sorry for going cold on this. I hadn't even gotten to writing up the interesting part of my experimentation! I'm massively impressed by the speedup you achieved with pure vcpu code. My first impression was that rather than vindicating my approach, it made it look pointless! But... [*] W...

The invisible bug would make a difference. There is code in CalcSet that bails out when one is inside the first lobe (the buggy one) or the cardioid. If that code fails, you're good for 64 iterations of the Mandelbrot function on each pixel... It certainly did! Fixing the constant (I'd just forgott...

Part 4: An invisible bug For practical reasons it seemed like investigating whether I was uniformly faster was the first thing to investigate. It seemed easier than trying to measure the impact of stall, and depending on what I found it could have a big impact on what I did next. My plan was this -...

Part 3: A benchmark Thanks everyone for your interesting responses above. As I'm writing these retrospectively, some of the steps I'm going to describe taking in future will seem odd in light of the excellent points you've already made - and that's just because I didn't have the benefit of your wis...