Search found 22 matches

by qwertyface
02 Dec 2020, 10:15
Forum: Hardware and software hacking
Topic: List of possible Gigatron mods
Replies: 13
Views: 1029

Re: List of possible Gigatron mods

This got me thinking. Who else has written (native) code for the Gigatron? Obviously Marcel and there is one other project I'm aware of - https://hackaday.io/project/168293-gigatron-forth Working directly with the op-codes is a significant undertaking and it looks like the Gigatron Forth project mi...
by qwertyface
28 Nov 2020, 14:54
Forum: Hardware and software hacking
Topic: The Shift Table
Replies: 4
Views: 304

Re: The Shift Table

I think I get it now. The effect of the formula is to set the first "insignificant" bit to a 0, and all the bits below to 1. So shifts by 1 all get indexes of the form xxxxxxx0. Shifts by two get indexes of the form xxxxxx01, and shifts by three get indexes of the form xxxxx011. This means longer sh...
by qwertyface
28 Nov 2020, 12:41
Forum: Hardware and software hacking
Topic: The Shift Table
Replies: 4
Views: 304

Re: The Shift Table

Thanks at67 - but I really meant how is the lookup table constructed. I think I partly get it: For a shift of 6 places, there are only two of the original bits in the result, so it only needs 2²=4 rows in the table. For 5 places there 3 bits, so 8 rows, and so on, up to shifts of 1 bit, which have 7...
by qwertyface
27 Nov 2020, 17:36
Forum: Hardware and software hacking
Topic: The Shift Table
Replies: 4
Views: 304

The Shift Table

I've just started trying to implement arbitrary left and right bit shifts - I need to be able to shift 16 bit quantities by up to 15 places. This led to me looking at the right shift table in page 5 of the ROM. I think I understand how to use it (although I think doing so would require fitting my ow...
by qwertyface
22 Jul 2020, 16:04
Forum: Kit assembly gallery
Topic: My own PCB
Replies: 4
Views: 1293

Re: My own PCB

Didn't the eevBlog have red ones for the four-layer ones?
by qwertyface
26 Jun 2020, 12:09
Forum: Hardware and software hacking
Topic: Parsec - I'm making a game
Replies: 14
Views: 3050

Re: Parsec - I'm making a game

Given I'm a Ruby developer, I've taken a bunch of inspiration from the existing vASM assembler written in Python and gone about learning the architecture and instruction set. It's been super fun! I'm a Python guy, but I must say that I think your vASM as a Ruby embedded DSL looks really nice - very...
by qwertyface
29 May 2020, 10:25
Forum: Hardware and software hacking
Topic: Interrupts:
Replies: 11
Views: 8091

Re: Interrupts:

[Partly replying just to keep conversations going on this forum] I'd been wondering if a good use for the vBlank interrupt would be to implement a keyboard buffer for programs like BASIC. Perhaps using a small ring buffer, of say 32 characters, or less. I think it would be easy for slow programs to ...
by qwertyface
27 May 2020, 08:14
Forum: Escape Meta Alt Control Shift
Topic: In memoriam Marcel
Replies: 18
Views: 6577

Re: In memoriam Marcel

Thank you for letting us know Walter, and I'm so sorry for your loss. You said that you hoped that his brilliance and optimism has inspired others; they certainly inspired me! I've learned a huge amount in a short time from my journey with the Gigatron, and in particular from Marcel's code. But just...
by qwertyface
01 Apr 2020, 14:11
Forum: Hardware and software hacking
Topic: Alternative Languages
Replies: 4
Views: 2850

Re: Alternative Languages

Yes, that all makes perfect sense. I'm continuing to learn a lot from the Gigatron - especially about what is and isn't easy!

I'd like to see Forth become a viable alternative to C for writing larger programs on the Gigatron - but C on vCPU, will likely prove to work better in practice.
by qwertyface
01 Apr 2020, 09:48
Forum: Hardware and software hacking
Topic: Alternative Languages
Replies: 4
Views: 2850

Re: Alternative Languages

Here are a few strands of thought on virtual machine design. I don't know if they add up to anything - but if you were to design a new language with the Gigatron in mind, choosing an appropriate execution model seems half the battle. I'm increasingly wondering if Forth isn't such a great fit for the...