Title: ZX81/Timex
Programming in BASIC
& Machine Language
Author: Ekkehard Floegel
Publisher: Elcomp
POB 1194
Pomona, CA 91769
Price: $9.95, 139 pps.
Programming takes up where your ZX/TS manual leaves off; the book assumes you know the basics of ZX/TS hardware and software.
Beginning chapters include game, graphic, educational, and data management programs. Eight game programs and the “vehicle log book program” nicely illustrate some good programming techniques (arrays and decimal point alignment). The author provides good programs that create basic graphics motion, along with programs for falling bodies, shooting objects, plotting and vector effects of gravity and horizontal velocity (i.e. mortar shots). Unfortunately, these contain many typographical errors. Chapter four covers school programs, including 12 mathematical programs. Well written data management programs clearly show how to set up, maintain and sort data files.
Unfortunately, Floegel gives only a brief discussion of machine language, in chapter six. This chapter serves mostly those who already have some idea of how to use ML. A good, short ML monitor program enhances the ML section. About 30% of the book discusses machine language.
Chapters seven and eight discuss the Z80 PIO chip, and provide a complete schematic for construction of an inexpensive I/O board, with software. Although the author refers to a special set of prototype boards, you could use almost any ACE (all circuit evaluator, or white board) to build the three-chip I/O port.
Despite grammatical errors such as choppy sentences, wrong word order, and singular word forms for plural (due to translation from the original German) and style (half-size, typed pages) the book remains quite readable. Good BASIC routines, the ML monitor program and a simple I/O port proposal justify this book’s $9.95 price tag (fixing the many typos would increase its value).