Sub-Etha Software
Blogs

Reversing bits in C

December 2, 2022 Sub-Etha Software

In my day job, we have a device that needs data sent to it with the bits reversed. For example, if we were sending an 8-bit value of 128, that bit pattern is 10000000. The device expects the high bit first so we’d send it 00000001. In one system, we …

Blogs

Transcoding is flying along!

December 2, 2022 Retro Ports

Progress has been relatively quick through the ground-based objects; it has mostly been a case of filling out a few more simple instruction sequences for handlers that were half-finished. Most of the lower-level routines used in the handlers have already been transcoded and tested. The first flying enemy has appeared; …

Sub-Etha Software
Blogs

ChatGPT AI can analyze 6809 assembly language!

December 2, 2022 Sub-Etha Software

I gave it this: clear lda #96 clearA ldx #1024 loop sta ,x+ cmpx #1536 bne loop rts …and ChatGPT gave me this: The clear subroutine in this code is used to clear the screen and initialize it with a grid of green squares. The subroutine begins by loading …

Blogs

Progress is on target!

December 1, 2022 Retro Ports

I’ve fixed the shooting routines; now there’s no doubt they’re all targeting the Solvalou! Those Derotas are on target! The “bullet-hell” I was seeing had me concerned; it’s not as if the firing frequency logic was all in one routine – every object has its own logic, even if it …

Blogs

A shot in the dark at how this all works!

December 1, 2022 Retro Ports

Today I decided to implement bullets which meant going back to RE some of the code that calculates the bullet trajectory. TBH it did (and still does) my head in a bit; I understand what it’s trying to do and roughly how it’s doing it, but some of the finer …

No Picture
Blogs

Streaming large files on the CoCoSDC

November 30, 2022 Glen's Weblog

Back in 2017, Ed Snider released a cool video and audio player for the CoCoSDC on a CoCo 1. I thought it was wicked and at that time I remember fighting with the CoCoSDC to try and get some of … Continue reading → …

Blogs

Progress is on-path!

November 30, 2022 Retro Ports

Domogram was one of the more complicated ground-based objects and I must say the implementation went pretty smoothly. It’s the object that seemingly ‘follows’ paths. The circling Domograms on Level 7 Of course it’s all pre-canned routes programmed via a list of vectors comprising dX,dY and length components. The map …

Break Into Chat
Blogs

Unearthed: Kirschen’s “Music Creator” for IBM PC

November 29, 2022 Break Into Chat

Decades before the debut of DALL-E, Israeli cartoonist Yaakov Kirschen was developing an “artificial creativity” system to let computers compose their own music, by extracting components of existing songs and combining them in new ways. The software was originally written for the Amiga, but business changes led them to abandon …