ZX Computing

Spectrum Machine Language For The Absolute Beginner
By Melbourne House
Spectrum 48K

Published in ZX Computing #5

Spectrum Machine Language For The Absolute Beginner

This book is designed as an introductory text to the field of machine and assembly language programming for the ZX Spectrum.

Inside the book, there are five section headings, each of which has been split up into a number of sub-secions. The first section is called 'Finding your way around in machine language' and starts from the very beginning, assuming absoutely no prior knowledge of working with machine language. From the basics, though, you quickly move onto how to manipulate the stack, loops and jumps, use of subroutines and block operations.

The second section of the text deals with 'Instructions that are less frequently used' and covers register exchanges, rotates and shifts, interrupts and restarts, and many others. As in the first section of the book, the text is liberally sprinkled with examples for you to try and most of the sections end with either a summary of the information in that section or a number of exercises for readers to work their way through.

The next section, 'Programming Your Spectrum', deals first with the planning of a program; this is fairly comprehensive, dealing mainly with the 'top-down' approach to disciplining your programming. Then the authors take a look at the Spectrum itself, paying particular attention to the keyboard, the video screen display and the sound output.

The last two sections concentrate on actual programs listed within the text. Looking ffirst at monitor programs, there are two provided: EZ-Code Machine Language Editor and HexLoad Machine Code Monitor. As well as clearly reproduced listings, the programs are accompanied by an explanation of each.

The last section concentrates on the production of one program, Freeway Frog, which is isted over 36 pages of the book. From first programming principles, the structure of the program is planned, developed and finally put together to form a complete listing.

There are seven appendices, with useful data you'll need when you begin experimenting with machine and assembly language yourself.

Spectrum Machine Language For The Absolute Beginner, edited by William Tang, is published by Melbourne House. The book has 243 pages and is priced at £6.95. ISBN 0 86161 1101.