---
title: "Asteroids (Syntax)"
id: 76312
type: "computer_media"
slug: "asteroids-syntax"
url: "http://localhost/computer_media/asteroids-syntax/"
markdown_url: "http://localhost/computer_media/asteroids-syntax.md"
published_at: "2026-11-11T08:03:12+00:00"
modified_at: "2026-11-11T08:03:12+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2026/11/asteroids-syntax-1.png"
excerpt: "Dodge falling asteroids by steering your ship left and right in this compact machine-code game, typed in as a REM line and a short BASIC launcher."
post_tag:
  - name: "Downloadable"
    slug: "downloadable"
    taxonomy: "post_tag"
    url: "http://localhost/tag/downloadable/"
  - name: "TS 1000"
    slug: "ts1000"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts1000/"
  - name: "ZX81"
    slug: "zx81"
    taxonomy: "post_tag"
    url: "http://localhost/tag/zx81/"
model:
  - name: "Sinclair ZX81"
    slug: "zx81"
    taxonomy: "model"
    url: "http://localhost/model/zx81/"
  - name: "Timex/Sinclair 1000"
    slug: "ts-1000"
    taxonomy: "model"
    url: "http://localhost/model/ts-1000/"
indiv:
  - name: "Craig Bird"
    slug: "craig-bird"
    taxonomy: "indiv"
    url: "http://localhost/indiv/craig-bird/"
genre:
  - name: "Arcade"
    slug: "arcade"
    taxonomy: "genre"
    url: "http://localhost/type/arcade/"
media_type: "Program"
programmers:
  - name: "Craig Bird"
    slug: "craig-bird"
    taxonomy: "indiv"
    url: "http://localhost/indiv/craig-bird/"
download_url: "https://archive.org/download/timex-sinclair-software-archive/Asteroids%20%28Syntax%29%20%281984%29%28Bird%2C%20Craig%29%28TS1000%29%28CA%29%28Program%29.zip"
mediadate: "1984"
images:
  - url: "http://localhost/wp-content/uploads/2026/11/asteroids-syntax-1.png"
  - url: "http://localhost/wp-content/uploads/2026/11/asteroids-syntax-2.png"
  - url: "http://localhost/wp-content/uploads/2026/11/asteroids-syntax-3.png"
article_media:
  - id: 19850
    title: "Asteroids"
    type: "article"
    url: "http://localhost/article/asteroids/"
related_content:
  - id: 19616
    title: "Dear Editor"
    type: "article"
    url: "http://localhost/article/dear-editor-18/"
media_type_tags: "Arcade"
license: false
---

# Asteroids (Syntax)

A fast machine-code game: asteroids fall from the top of the screen toward a ground line, and you steer your ship left and right with 5 and 8 to dodge them. Each asteroid you avoid scores a point; after a hit, press any key to start a new game.

The program is a 399-byte machine-code routine held in a line 10 REM. The article has you type a short loader, RUN it and enter the bytes from a POKE list, then replace lines 20-50 with the four-line launcher (SLOW, RAND USR 16514, PAUSE 4E4, GOTO 30). The download has the machine code already in place.

Published in Syntax March 1984 ([Asteroids](https://timexsinclair.com/article/asteroids/)).

## Source Code

```
  10 REM 123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456
  20 SLOW
  30 RAND USR 16514
  40 PAUSE 4E4
  50 GOTO 30
```