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 …
code · How-To
16-bit Unsigned AND on Commodore 64
Implementing 16-bit unsigned AND operations in Commodore BASIC using two’s complement to work around the signed integer limitation.
code · Getting Started
10 PRINT for the KIM-1
Implementing 10PRINT on a KIM-1 clone (PAL-II) in both Microsoft BASIC and 6502 assembly, displaying the maze on the 7-segment LED display.
code · Getting Started
wAx the VIC-20
Exploring wAx, a native assembler for the VIC-20 that integrates with BASIC. Includes examples implementing 10PRINT and Fibonacci in assembly directly …
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 …