---
title: "Totally Safe Machine Code for the ZX81 and TS-1000"
type: "article"
slug: "totally-safe-machine-code-for-the-zx81-and-ts-1000"
url: "http://localhost/article/totally-safe-machine-code-for-the-zx81-and-ts-1000/"
markdown_url: "http://localhost/article/totally-safe-machine-code-for-the-zx81-and-ts-1000.md"
published_at: "2026-03-14T14:06:49+00:00"
modified_at: "2026-03-14T14:06:50+00:00"
featured_image:
  url: "http://localhost/wp-content/uploads/2022/04/20230809-041332.jpg"
excerpt: "Technique for safely embedding machine code in REM statements on the ZX81 and TS-1000, using two template types that together provide 112 bytes or more of machine code space. Includes a memory address map showing where each template stores its code, and the critical restriction that CHR$(13) (ENTER) must never appear in the machine code."
category:
  - name: "Timelinez"
    slug: "timelinez"
    taxonomy: "category"
    url: "http://localhost/category/periodicals/timelinez/"
post_tag:
  - name: "Machine language programming"
    slug: "machine-language"
    taxonomy: "post_tag"
    url: "http://localhost/tag/machine-language/"
  - name: "TS 1000"
    slug: "ts1000"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts1000/"
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/"
publication_r:
  id: 21571
  title: "Timelinez"
  type: "periodical"
  url: "http://localhost/periodical/timelinez/"
volume: "5"
issue: "1"
issues_articles:
  - id: 38845
    title: "Timelinez v5 n1"
    type: "issue"
    url: "http://localhost/issue/timelinez-v5-n1/"
pages: "261"
pubdate: "January 1987"
archive_link: false
---

# Totally Safe Machine Code for the ZX81 and TS-1000

Technique for safely embedding machine code in REM statements on the ZX81 and TS-1000, using two template types that together provide 112 bytes or more of machine code space. Includes a memory address map showing where each template stores its code, and the critical restriction that CHR$(13) (ENTER) must never appear in the machine code.