80-Bus News

Z80 Assembly Language Programming for Students by Roger Hutty, published by Macmillan, cost approx £5.

This is a “slim volume” (127p) which deals quite adequately with the use of Z80 assembly language and an assembler. It would make a reasonable starting point for a beginner at machine code. In his treatment of the instruction set, the author deals only with the simplest of the Input/​Output instructions, and mentions the interrupts, so this is not the book to buy if you intend to get into the interrupt setup very quickly, but for the beginner, a fairly clear introduction to assembly language.

Introduction to the Z80 Microcomputer by Adi J. Khambata, publ. John Wiley costing about £12. (330+pages)

This author has written a textbook on microprocessors and an associated series of processor specific manuals, of which this is the Z80 version. As I have not seen the major textbook, I cannot comment on it, but without any doubt, this book contains the best discussion of all the Z80 family peripheral chips I have seen, dealing with their programming and timing requirements. It should not be necessary to purchase the main manual if you had any experience in using the Z80 (or had read, marked and inwardly digested the 80-BUS News!). This book takes up the subject a little bit further along from where Hutty leaves it down.

A Z80 Workshop Manual by E.A. Parr, published Babani, £2.75, (184 p).

This is a ‘paperback’ sized book that gives as good a survey of the Z80 and peripheral chips as one could reasonably expect. It deals with the types of instructions, the architecture of the CPU, the addressing modes, instruction set, assembly language programming, and use of some of the Z80 family peripheral chips. It also must endear itself to us as it’s examples of hardware configuration and monitor facilities are based on the Nascom – albeit with Nasbug monitor. I think this would form a good and very reasonably priced introduction to the intricacies of Assembly Language and the Z80 for the beginner.

A Practical Introduction to Pascal – with BS 6192 by I.R.Wilson and A.M.Addyman published Macmillan (approx £6)

This is the latest edition of these authors’ book on Pascal programming. It includes the text of the British Standard for Pascal, which is interesting if only to read exactly how a language is defined. I note one surprising omission from the standard – during the discussion over the last few years leading to the adoption of this standard, it was generally agreed that the ‘case of’ structure should have an ‘otherwise’ extension to allow for the exceptional situation where the operator did not match a case-constant. This seems to have been deleted before adoption of the standard. The textbook is succinct and to the point, being based on the introductory lectures in programming in Manchester. It is liberally illustrated with example programs, and would make a good starting point to find out about the language.

So far, so good. I haven’t mentioned CP/M even once. Now comes the denouement, as the Bishop said to the Actress! One of the problems with CP/M is that its manual – Digital Research’s CP/M Operating Manual – was, in its earlier incarnations, absolutely and utterly incomprehensible. Its latest version (July 1982) is slightly better, but suffers still from 8080 mnemonics and ‘clever’ use of macros. This has given rise to a plethora of books on CP/M, all written with the intention of explaining what shouldn’t need to be explained. It is with some of these that I propose now to deal.