code · How-To
SHA-256 on a Commodore 64, Five Times Faster
Back in 2021 I promised a closer look at SHA-256 on the C64. It turns out the old program got the wrong answer for anything 32 characters or longer. …
code · retro
Chladni Plates on a Commodore 64
Bow a metal plate covered in sand and the sand runs to the lines that don’t move. Change the note and it draws a new picture. Here’s why …
commodore · c64
The SID Chip Is a Reservoir Computer
Reservoir computing says don’t train the dynamics, just train the readout. I used the SID’s analog filter as the dynamics and one ridge …
code · retro
WOZMON, Eight CPUs, and a Paper Tape
Eight CPUs from the 1970s and 1980s, sharing one 64K bus, an Apple-1 style monitor on the front, and a paper tape station. Open it in your browser and …
C64 · code
Machine Language: Count Faster on 6502
Optimizing a simple counting loop on the 6502, progressing from slow BASIC to increasingly faster assembly implementations. A practical guide to 6502 …
C64 · code
A gentle introduction to two's complement
Understanding two’s complement: how computers represent negative numbers, why it simplifies hardware design, and how to work with signed …
C64 · code
Rail Fence Cipher on Commoodore 64 and TI 99/4A
Implementing the Rail Fence Cipher on the Commodore 64 and TI 99/4A. A fun transposition cipher for secret messages with kids.
C64 · code
Building a software serial bridge
Modern and retro mix One of my favorite peices of retro clone hardware is Bob Corsham’s KIM-1 Clone. I’ve featured it many places like the …