Commodore User

C16 Machine Language For The Absolute Beginner

Author: Ken McMahon
Publisher: Melbourne House
Machine: Commodore 16

Published in Commodore User #21

C16 Machine Language For The Absolute Beginner

Unpretentiously entitled C16 Machine Language For The Absolute Beginner, that's exactly what you get in this latest book from the pen of Peter Beresford. The complete novice to machine language is taken through everything they need to know about the C16 in a mere 150 pages. Don't be deceived by the slimness of this volume, it includes just about everything you need to know to start writing your own machine code programs. Mr. Beresford leaves out much of the padding so many other authors find it necessary to include, making this book just as informative as many twice its size.

There are twelve chapters in all, none of which is more than ten pages long. Each topic is therefore concisely covered in sufficiently short a space for the reader to maintain concentration and interest. The book begins with an introduction to machine language, explaining the advantages in memory and speed to be gained over Basic. Then you are introduced to the internal architecture of the 7501 micro-processor with the help of some simple machine language programs. Next is a break from the keyboard to introduce some conceptual problems, namely the relationship between decimal, hex, and binary numbering systems. This is explained by means of the much used 'eight fingered hand' analogy. Following a brief introduction to the C16's resident monitor, TEDMON, you get to grips with the more powerful tools of the machine language programmer's trade. Successive chapters deal with, among other things, the various addressing modes, branch instructions, use of the index registers, logical operators and the C16's KERNAL system. Each chapter deals clearly with the subject, using programs to illustrate the techniques involved. At the end of each chapter a brief summary encapsulates the major points.

The appendices, as usual, include all the information you can find in Commodore's own literature, but with some added bonuses. One section deals with what to look for when buying a good assembler. Also included are detailed memory maps and a description of the C16's TED chip.

C16 Machine Language For The Absolute Beginner is a well written comprehensive guide suitable for any C16 owner thinking of tackling machine code for the first time. If that description applies to you, give serious consideration to splashing out six quid on it. An excellent little book.

Ken McMahon