Skip to content
People

Toni Baker

Voice of ZX assembly

Toni Baker's 'Mastering Machine Code on Your ZX Spectrum' taught a generation of British programmers how to escape BASIC and write real games.

zx-spectrum educatorsauthorsassembly 1954–present

Overview

Toni Baker wrote the book that transformed Spectrum owners from BASIC dabblers into assembly programmers. Mastering Machine Code on Your ZX Spectrum (1983) combined clear explanations with practical examples, providing the roadmap thousands followed into professional game development.

Fast facts

  • Background: mathematics graduate turned technical author.
  • Style: approachable yet thorough, with working example programs.
  • Impact: the standard reference for Spectrum assembly programming.
  • Approach: assumed readers knew BASIC but nothing of machine code.

Mastering Machine Code

The book covered:

TopicApproach
Number systemsHex, binary explained from scratch
Z80 registersWhat they are, how to use them
InstructionsGrouped by function, with examples
MemoryHow the Spectrum organises RAM and ROM
GraphicsScreen layout, plotting, sprites
SoundBeeper programming
IntegrationCalling machine code from BASIC

Teaching approach

Baker’s method worked because:

  • Gradual complexity: started simple, built understanding step by step.
  • Working code: every example could be typed in and tested.
  • Practical focus: aimed at game programming, not abstract theory.
  • Clear prose: avoided jargon, explained everything.

Influence

Many professional Spectrum developers cite Baker’s book as their entry point into assembly:

  • Provided the missing link between BASIC and machine code.
  • Made the intimidating Z80 instruction set approachable.
  • Created a common foundation for the UK development scene.

Publications

  • Mastering Machine Code on Your ZX Spectrum (1983) — Interface Publications
  • Further Mastering Machine Code — sequel with advanced topics
  • Regular columns in Spectrum magazines

See also