What Does This Assembly Code Do?
What does this assembly code do? What machine is it?
Assembly
6502 Illegal Opcodes in the Siemens PC 100 Assembly Manual (1980)
The 6502’s “illegal” opcodes were of intense interest to home computer enthusiasts, and analyses were published in various magazines. But one would have never expected a company like Siemens to document illegal opcodes in a programming manual from 1980.
Commodore’s Assemblers: Part 5: 6502ASM
In the series about the assemblers Commodore used for developing the ROMs of their 8-bit computers, this article covers the 1989 “Commodore 6502 Assembler” (6502ASM), a cross-assembler written in C that ran on VAX and PC.
Commodore’s Assemblers: Part 4: HCD65
In the series about the assemblers Commodore used for developing the ROMs of their 8-bit computers, this article covers the 1987 “HCD65” assembler that ran on the C128.
Commodore’s Assemblers: Part 3: BSO CY6502
In the series about the assemblers Commodore used for developing the ROMs of their 8-bit computers, this article covers the 1984 “Boston Systems Office” (BSO) cross-assembler running on VAX/VMS.
Commodore’s Assemblers: Part 2: MOS Resident Assembler
In the series about the assemblers Commodore used for developing the ROMs of their 8-bit computers, this article covers the 1976 “MOS Resident Assembler” that ran on a variety of 6502-based computers.
Commodore’s Assemblers: Part 1: MOS Cross-Assembler
In the series about the assemblers Commodore used for developing the ROMs of their 8-bit computers, this article covers the 1975 “MOS Cross-Assembler”, which was available for various mainfraimes of the era.
Commodore’s Assemblers: Overview
Commodore used 5 different assemblers, most of them in-house tools, to build the ROMs for their Computers like the PET, the C64 and the C128. Nevertheless, all Commodore source files, from 1975 to 1990, share a common format and use the same assembly directives. This series of articles describes each of these assemblers.
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:
Ultimate Commodore 64 BASIC & KERNAL ROM Disassembly
My side-by-side C64 ROM disassembly/commentary page has been completely redone!
Building the Commodore TED Kernal with Modern Tools
The original Commodore TED (C16, C116, Plus/4) source code has recently appeared on zimmers.net. It is also available in my Commodore Source Code git repository.
62 Reverse-Engineered C64 Assembly Listings
Between 1992 and 1995, I reverse engineered Commodore 64 applications by printing their disassemblies on paper and adding handwritten comments (in German). These are the PDF scans of the 62 applications, which are 552 pages total.
Building the Original Commodore 64 KERNAL Source
Many reverse-engineered versions of “KERNAL”, the C64’s ROM operating system exist, and some of them even in a form that can be built into the original binary. But how about building the original C64 KERNAL source with the original tools?
Macross 6502, an assembler for people who hate assembly language
There are many MOS 6502 cross-assemblers available. Here’s a new one. Or actually a very old one. “Macross”, a very powerful 6502 macro assembler, which was used to create Habitat, Maniac Mansion and Zak McKracken, was developed between 1984 and 1987 at Lucasfilm Ltd. and is now Open Source (MIT license):
Making Obsolete Code Run Again: The mxass 6502 Cross Assembler
Here’s the challenge: Take code that you wrote some 20 years ago in an obsolete programming language for an obsolete platform, make it run on a modern system (without emulation!)… and actually make it useful!
Comparative C64 ROM Disassembly Study Guide
The Commodore 64 ROM has been subject to immense reverse engineering. Many commented disassemblies were published over the decades, scattered over different media such as books, magazines, disks, and later, the internet – and there are even some commentaries that apply to the C64 ROM, but were written with other systems in mind that shared Microsoft’s BASIC interpreter.
Fully Commented Commodore 64 BASIC ROM Disassembly – based on Microsoft’s Source
On my quest of collecting as many commentaries on the Commodore 64 ROM at pagetable.com/c64rom, we have gathered Lee Davison’s excellent commentary, the German de facto standard by Data Becker, and an adaptation of Bob Sander-Cederlof’s Apple II ROM commentary, all in the same cross-referenced HTML format.
Microsoft BASIC for 6502 Original Source Code [1978]
This is the original 1978 source code of Microsoft BASIC for 6502 with all original comments, documentation and easter eggs:
Fully Commented Commodore 64 BASIC ROM Disassembly – based on Applesoft!
In our series about C64 ROM commentaries (English version by Lee Davison, German version by Data Becker), I’m now presenting a most unusual C64 ROM commentary – based on a commented disassembly of the Apple II ROM.
Fully Commented Commodore 64 ROM Disassembly (English)
After last week’s German C64 ROM disassembly from the “64 intern” book, I have now also converted Lee Davison’s commented disassembly into the same format.