As the title suggests, the "Z-80 Reference Guide" is not a teach yourself Z-80 assembly language book. It is intended as a reference book for competent Z-80 programmers and also for users with some experience of assembly language who wish to expand their knowledge.

The book contains a treasure trove of information for the Z-80 programmer. Beginning with various flags and the effect of the range of Z-80 instructions upon their status. Moving on, we come to the Z-80 instruction set, which appears twice. Firstly they are presented as groups which have a specific function or activity, e.g. single byte load groups, two byte arithmetic group, and rotate and shift group. Displayed in tabular format with a short descriptive paragraph, they are also cross-referenced to the chapter containing the second version of the instruction set. These are merely presented in alphabetical order but each instruction has at least one page of information devoted to it.

The information given is very comprehensive, it consists of the object code in decimal and hex, a written description of the action carried out by the instruction, a table showing the effect upon each of the flags, and an example of its use. One final chapter worth mentioning is a short but very useful section of hints and tips. This consists of several routines which may be second nature to the experienced user, but could save the novice hours. The Z-80 reference guide is a book that no Z-80 programmer should be without.

J.R.