One advantage to the BBC is that it can be easily programmed in machine code.

The first chapter of this book is an introduction and covers the differences between Basic I and Basic II, and how to overcome them. The next chapter covers the reading of the function keys with two programs virtually copied from an old edition of Acorn User. The author makes no bones about this and offers profuse thanks. Next comes a chapter on machine status, with routines that will tell you your program size and what variables are currently in use.

Eventually the book gets down to a little meat with a selection of routines to provide multi-byte arithmetic. There is very little explanation of how this works, which is a shame, as they use standard methods which would be of interest to anyone wanting to modify them.

The most unusual part of the book is a list of some of the programs in bar code form. If you happen to have an MEP (Micro Electronics Educational Program) bar code reader you will save yourself a lot of strain.

Overall, the book provides useful reference material for people who have just begun writing machine code programs. On the other hand, if you are writing machine code already you probably have these programs in stock.

Kenn Garroch