# microsoft/BASIC-M6502

Microsoft BASIC for 6502 Microprocessor - Version 1.1

Repository: https://github.com/microsoft/BASIC-M6502
Canonical: https://ross.abutalabs.com/products/basic-m6502
Language: Assembly
License: MIT
License Family: permissive
Topics: 6502-assembly
Archived: true
Last push: 2025-09-03T18:39:33+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 40, release rhythm 35, longevity 29
- inputs: {"age_days": 413, "days_push": 364, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4499, forks 510 (observed 2026-08-28T04:08:51.454721+00:00)

## What it is
The original assembly source code for Microsoft BASIC Version 1.1 for the 6502 microprocessor, released under MIT license. It is a historically significant 1976-1978 interpreter that powered early personal computers like the Apple II, Commodore PET, OSI, and KIM-1.

## Use cases
- study the source code of Microsoft's early BASIC interpreter
- build a BASIC interpreter for a 6502-based retro computer
- run BASIC on an Apple II or Commodore PET emulator
- learn 6502 assembly from a real historical codebase
- port a vintage BASIC interpreter to a homebrew 6502 system
- research the history of early personal computer software

## When to choose
- you want authentic, historically significant 6502 assembly source code
- you are building or emulating a vintage 6502 machine and need a BASIC ROM
- you are teaching or learning assembly language and interpreter design

## When to avoid
- you need a modern BASIC interpreter with contemporary features
- you want a maintained, production-ready programming language implementation
- you are not comfortable reading 6502 assembly with conditional compilation for 1970s hardware

## Facets
- artifact type: learning-resource
- maturity: maintenance
- function: interpreter, programming-language, compiler
- domain: programming-languages, operating-systems, education
- platform: cpp, cross-platform, embedded
- tags: 6502-assembly, basic-interpreter, vintage-computing, retrocomputing, historical-source-code, apple-ii, commodore-pet, kim-1, emulation, retro-computing

## Member repositories
- microsoft/BASIC-M6502 (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:51.454721+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:22:04.775132+00:00, confidence not recorded.
  - readme: https://github.com/microsoft/BASIC-M6502 (fetched 2026-08-28T04:08:51.454721+00:00, sha b047a4bf5dd8)
- Data as of 2026-08-30T08:39:29.467469+00:00.