Gigatron Hackers

I haven't explored it. Making a 25 MHz VGA circuit on a PCB is pushing things for most people. You'd need tricks such as using 74ACT logic and likely pipelining. If the Gigatron is driving it, it would be simpler in that you wouldn't need a sync circuit, and the CPU has no problem with producing the...

Okay, I've come up with an idea in my mind for multiplication. It would take 8 cycles plus any overhead. The idea is 8/8/16 unsigned. I realized that you can do it the same way as you multiply by hand. It is just place, add, and shift. The way this would work is to use shift registers and adders, an...

Thank you Monosonite! I still haven't started as I'm trying to work it out in my mind. My focus is now more on what amenities can be added to the base hardware to make interpretation easier. Things like: 1. Proper flags and related instructions. If we had proper ADC/SBB instructions, chaining additi...

I'll touch on what is already here and then post some ideas. I use "Gigasimilar" to refer to homebrew ideas/projects that heavily borrow from the Gigatron. We really shouldn't try to promote something as a "Gigatron 2.0" or similar since you cannot significantly "improve&quo...

Ah yes, Xpp is also X++. The pp part is "plus plus," so post-increment X.

Yes, that was what I assumed as I was first reading. The controllers operate at different voltage levels and have some quality control issues. As for where the inputs were coming from, I would guess it could be an improperly soldered connection in the controller. It is a serial device, so it would n...

I've noticed that.

Thank you Monosonite! I agree, the Gigatron fits the design philosophy well. I'm seriously considering spinning something similar. I think I'd want to play with some working pulls of the limited 16-bit ALUs that were around. They could replace at least 10 chips (and possibly more such as the accumul...

For a Gigatron-similar machine, it might take more than 20 chips to double the ALU width at a reasonable speed. That would likely double the worst-case latency since carry ripples don't scale well. You'd have 2 additional ripples. There used to be a carry generator chip to speed up adders and ALUs, ...

I will ask again: Does any software rely on the row and column data? I don't mean the indirection table, but the current line that is being processed on the screen. I mean, how does it know which line to start on and which indirection entry to look up? How does the clock program know how many second...