This repository contains a Motorola 68000 assembler (asm68) and disassembler (dis68), both written in Go.
The assembler converts Motorola 68000 assembly source code into machine code, while the disassembler performs the reverse—translating binary machine code back into human-readable assembly.
Both tools are designed to be lightweight, portable, and easily extendable. They follow the Go convention of having separate command-line tools under the cmd/ directory.
cmd/
├── asm68/ # Assembler CLI tool
└── dis68/ # Disassembler CLI tool
The assembler currently supports all standard addressing modes, most core instructions, and recognizes labels and .org directives.
The .org directive is currently parsed for completeness and future expansion but does not affect output layout yet. There is not yet a binary or object format that uses absolute addressing, so .org has no effect other than reserving the address internally.
To build both tools:
go mod tidy
go build -o bin/asm68 ./cmd/asm68
go build -o bin/dis68 ./cmd/dis68Or use the preconfigured VSCode build tasks (see .vscode/tasks.json).
The compiled tools will be located in the bin/ directory.
asm68 input.asm output.bindis68 input.bin output.asmOr, to print it to the terminal, omit the output:
dis68 input.bin.
├── assembler/ # Core assembler logic (mnemonic parsing, operand encoding)
├── cpu/ # CPU constants, opcodes, addressing modes, endianness helpers
├── disassembler/ # Disassembler logic (in progress)
├── cmd/
│ ├── asm68/ # Assembler CLI
│ └── dis68/ # Disassembler CLI
└── README.md
- Implement
.org-based binary layout control. - Add full disassembler support for all instruction types.
- Introduce an object format for relocatable assembly.
- Add test suite covering all 14 addressing modes and instruction types.
MIT License © 2025 Ronny Bangsund