C64

Matrix fundamentals from the ground up. Definitions, the operations that matter, plain Python, numpy for comparison, and a complete BASIC program on a …

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 …

Where the famous 43 quintillion comes from, why a C64 can’t print it the easy way, and a tiny multi-precision multiplier in BASIC that gets …

The fruit fly has a brain structure that acts like a hash function. I built it in Python, matched the 2017 paper’s MNIST results against a …

The Bombe needs a crib. What if you don’t have one? Index of coincidence measures how much an output looks like real language vs random noise. …

John Wallis found an infinite product for pi in 1655. Multiply enough fractions together and pi falls out. We run it on the C64 in BASIC and assembly, …

Ring settings multiply Enigma’s keyspace by 17,576. We add them to our C64 emulator, see why brute force alone can’t keep up, and set the …

The Commodore 64 searches nearly six million Enigma M3 configurations to find the one that matches a known plaintext crib. First the concept, then …

A working Enigma M3 emulator on the Commodore 64. First in BASIC for clarity, then in 6502 assembly for speed. Eight rotors with dual notches, …

Visualizing sorting algorithms in real-time on the Commodore 64 using PETSCII characters. Three classic algorithms rendered as animated bar charts in …

Exploring three different maze generation algorithms on the Commodore 64: Depth-First Search, Randomized Prim’s, and the classic 1981 algorithm …

Implementing 16-bit unsigned AND operations in Commodore BASIC using two’s complement to work around the signed integer limitation.

Why your algorithm choice matters: comparing linear search O(n) vs binary search O(log n) with implementations in Commodore BASIC and Python.

Optimizing a simple counting loop on the 6502, progressing from slow BASIC to increasingly faster assembly implementations. A practical guide to 6502 …

Building and verifying the Commodore 64 SID chip’s 23-bit LFSR in hardware on a breadboard and comparing the output against the actual SID chip.

An introduction to Linear Feedback Shift Registers: how they work, building one on a breadboard with shift registers and XOR gates, and implementing …

Commodore BASIC 2.0 A lot of fun with binary numbers can be had by printing them to the screen. This is a quick post to show how to do that with …

Understanding two’s complement: how computers represent negative numbers, why it simplifies hardware design, and how to work with signed …

Solving the classic N-Queens puzzle using backtracking. Covers both iterative and recursive approaches with implementations on the Commodore 64.

Implementing the Rail Fence Cipher on the Commodore 64 and TI 99/4A. A fun transposition cipher for secret messages with kids.

Drawing grids for screen layout planning on the Commodore 64 and VIC-20. Comparing BASIC, Simon’s BASIC, and Super Expander approaches.

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 …

Driving LEDs from the VIC-20 and KIM-1 USR ports. Binary counting in the real world with vintage hardware.

Exploring the elegant maze generator from Compute! magazine (December 1981). A line-by-line breakdown of how this classic BASIC algorithm works.

Writing code to validate Pilish text—prose where word lengths match the digits of Pi. Implementations in Julia and Commodore BASIC.

Evaluating vintage computers for NaNoWriMo 2022: VIC-20, Plus/4, Commodore 64, and PET. Word processing on 8-bit machines with SpeedScript and other …

Optimizing 6502 memory transfers beyond the general-purpose approach. Testing on a 1MHz KIM-1 clone with precise timing measurements.

Testing real-world memory transfer speeds on 6502 machines. Inspired by Apple M2 marketing, let’s see what Commodore hardware can actually do.

Implementing 64-bit arithmetic in 6502 assembly to solve the wheat and chessboard problem. Handling numbers too large for standard calculators on …

Extending Commodore BASIC with a PRINT AT command using machine language, then using it to visualize the 100 door problem.

Visualizing the poor randomness of RND() on the Commodore 64 and 128 compared to the PET and Plus/4. Clear patterns emerge when you plot the output.

A quick technique for splitting the Commodore 64 screen into two solid colors by manipulating VIC registers and screen memory.

Generating all 362,880 permutations of 1-9 the hard way: understanding algorithms instead of relying on library functions. Implementations in Python, …

Attempting the annual Advent of Code challenge on vintage 8-bit computers. Completing about 60% of puzzles on Commodore hardware.

Implementing Tower of Hanoi with SID sound on the Commodore 64, inspired by Numberphile’s Ayliean MacDonald video.

Testing the Commodore 64’s random number generator by simulating dice rolls and comparing the frequency distribution to theoretical values.

Calculating Pi on a Tandy Color Computer 2 with basic (non-Extended) BASIC. Working around the missing exponent function.

Solving the classic 100 door problem with visual output on multiple vintage systems: VIC-20, C64, PET, Atari, and Color Maximite.

How to load and run Commodore 64 BASIC programs on a PET. Working around the PET’s lack of program relocation.

Generating pseudo-random numbers with the Lagged Fibonacci Sequence on the VIC-20. Building reusable BASIC subroutines for the cipher toolbox.

Porting Robin’s VIC-20 Super Expander programming challenge to the Commodore 64 using Super Expander 64 and Simon’s BASIC.

Documenting oscilloscope readings from working vintage computer chips to help diagnose faulty machines. A collaborative troubleshooting resource.

How to perform modulo operations in Commodore BASIC 2 without a cartridge. A one-line solution for VIC-20 and C64.

Implementing Pontifex/Solitaire—the playing card cipher from Cryptonomicon designed by Bruce Schneier—on the Commodore 64.

Generating one-time pads on a Commodore 64. Probably a bad idea for real security, but it looks cool.

Understanding hash collisions by finding them in a simple checksum from a 1984 type-in game. Demonstrating why weak hashes fail.

Finding prime numbers on the Commodore 64 for cryptographic purposes. A practical introduction to primes and primality testing.

How to display text character by character with delays in 6502 assembly using Turbo Macro Pro. A quick tip for a 12-year-old learning assembly.

Building a portable Commodore 64 development rig using a Pelican case, external monitor, and either TheC64 or Ultimate 64 for on-the-go retro …

Implementing the RC4 stream cipher on the Commodore 64, exploring the algorithm that powered WEP, WPA, and many other encryption protocols.

Repairing a Commodore 128 with bad RAM using DIY Chris’s RAM tester to diagnose and replace faulty 4164 memory chips.

Exploring pseudo-random number generation on the Commodore 64 using Linear Congruential Generators, a key building block for cryptographic …

Understanding the XOR operation and its magical properties for data recovery in cryptography and disk storage on the Commodore 64.

A deep dive video exploring hidden Easter eggs within an Easter egg on a 35-year-old album discovered using a Commodore 64.

A quick tutorial on determining string length in 6510 assembly language, comparing the approach to Python’s simple len() function.

Benchmarking BASIC execution speed across various retro computers using jiffy timing, comparing Commodore machines and other vintage systems.

How to use the Commodore 64’s jiffy clock for benchmarking in both BASIC and assembly language, measuring time in 1/60th second increments.

Recreating the WarGames movie launch code sequence on the Commodore 64, implementing brute-force hash table searching in assembly.

Calculating Pi using the Gregory-Leibniz series in BASIC on the VIC-20 for Pi Day, demonstrating the inefficient but educational iterative approach.

Comparing two assembly language approaches to counting to 16 million on the Commodore 64, demonstrating significant performance differences.

Comparing various video output improvements for vintage Commodore computers including RF modulator replacement, chroma resistor mod, and the …

Recreating the Terminator 2 ATM PIN cracker scene on the Commodore 64, using SID chip random numbers and 6502 assembly.

Building a Caesar cipher encoder and brute-force decoder on the Commodore 64, demonstrating how to crack simple substitution ciphers programmatically.

Implementing the shift cipher on the Commodore 64, encoding messages by rotating alphabet positions similar to a physical code wheel.

Replacing the RF modulator on a PAL Commodore 64C with an S-Video bypass board to dramatically improve video output quality.

Starting a series on implementing ciphers in Commodore assembly language, beginning with a simple string reversal as the first building block.

Implementing a one-time pad cipher by hand using dice-generated random numbers, inspired by the encryption methods in Cryptonomicon.

A beginner’s guide to learning 6502 assembly programming on the Commodore 64, including recommended tools, resources, and development …

Reviewing Soul Force and Outrage, two modern Commodore 64 games from Protovision being played on a PAL 64C.

A defense of using modern conveniences like LCD monitors, SD2IEC devices, and flash cartridges with vintage computers, explaining the practical …

A Christmas greeting featuring a Commodore 64 holiday demo video.

Reflections on getting back into 8-bit computing after building Ben Eater’s breadboard 6502, and why learning vintage assembly language …