Inside geoWrite – 5: Copy Protection
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses the geoWrite copy protection.
6502
Inside geoWrite – 4: Zero Page
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses how it makes maximum use of the scarce zero page space.
Inside geoWrite – 3: Font Management
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses the font manager’s system of caches for pixel fonts.
Inside geoWrite – 2: Screen Recovery
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses how the app manages to extend its usable RAM by 5 KB using a custom screen recovery solution.
Inside geoWrite – 1: The Overlay System
geoWrite is a WYSIWYG rich text editor for the Commodore 64 GEOS operating system, which runs with a total of just 64 KB of RAM. In the series about the internals of geoWrite, this article discusses how it manages to fit 52 KB of code into the available 23 KB of application RAM.
CMDR-DOS: Commodore DOS on FAT32
All disk drives connected to the Serial Bus of a Commodore 64 speak the Commodore DOS protocol, from the popular 1541 5.25″ drive to the modern sd2iec SD card interfaces. CMDR-DOS is a new and open source implementation of the Commodore DOS protocol, using SD cards with the FAT32 filesystem and supporting advances features like partitions, subdirectories and timestamps – and running on a 65c02!
FAT32 Filesystem for the 65c02
We are presenting the (to our knowledge) first full-featured open source library for 65c02 CPUs for accessing FAT32 formatted disks.
Ultimate Commodore Charset / PETSCII / Keyboard Reference
Another addition to the The Ultimate C64 Reference: We’re adding character sets, PETSCII codes and keyboard layouts – supporting eight different Commodore computers.
Ultimate C64 KERNAL API Reference
The Ultimate C64 Reference is growing again: This time, we’re adding the KERNAL API reference – as always, in eleven different versions side-by-side.
Ultimate C64 Memory Map
The system software of the Commodore 64 has been extensively reverse-engineered. Next to disassemblies of the ROM, several “memory maps” have been published: tables that document system variables in the first kilobyte of RAM, and how to tweak the system software with PEEK and POKE. Now, I’m presenting the Ultimate C64 Memory Map: A C64 memory reference that shows eight sources side-by-side.
Typos in the C64 Programmer's Reference Guide: C3PO or C3P0?
The Commodore 64 Programmer’s Reference Guide contains a memory map with a complete description of the zeropage and system variables used by KERNAL and BASIC, but now that we have the original source, we know there are three typos in this table.
Commander X16: Philosophy and Specification
I recently got involved in the Commander X16 project. I would like to give an overview of the project and the vision behind it from my perspective.
NES and SNES Controllers on a 6502 (like the C64)
NES and SNES controllers support 8 to 12 buttons with only three data pins (plus VCC/GND). Let’s attach them to a C64 – or any 6502-based system!
More Original Commodore Source Code
There have been a few new interesting additions to the Commodore Source Code repository, including:
Boxed MOS 6502 CPU
Back in 1975, you could order a boxed 6502 CPU directly from MOS in Norristown, PA. Here are some high-res photos of such a box and its contents.
Illegal Opcode Support for the Final Cartridge III Monitor
The monitor built into the Final Cartridge III is one of the best ones for the C64. Some of its unique features are:
Building and Hacking on the C64 KERNAL & BASIC with Modern Tools
The original Commodore 64 KERNAL and BASIC source code has been available for a while. It used to be built using Commodore’s assembler of a PET.
Reading the Raw Bits of a C64/1541 Disk without a Parallel Cable
An unmodified Commodore 1541 disk drive cannot transfer the raw bits of a whole track to the computer it is attached to: The Commodore Serial Bus is too slow to transmit the data in real time as it arrives from the read head, and the drive only has 2 KB of RAM, which is not enough to buffer the 8 KB of a whole track.