ASM-One is a comprehensive integrated development environment (IDE) and macro assembler specifically designed for Motorola 68000 (68K) assembly language programming on the Amiga. Developed by Rune Gram-Madsen and others, it features a built-in editor, debugger, and monitor, allowing developers to write, assemble, and test code within a single environment without leaving the system. It became one of the most popular development tools for demo and game programming during the Amiga's golden age, prized for its stability and feature-rich interface.