When high-level programming languages sorely needed simplification and clarification in the 1960s and 1970s, Niklaus Wirth came to the rescue with Algol W and Pascal, which evolved into Modula and Oberon. Now hardware description languages (HDLs) have just as great a need for simplification and structure. The two dominant HDLs, VHDL and Verilog, are, in Wirth’s words, “utterly unsatisfactory” for explanatory and tutorial purposes, “surpassing in complexity even large programming languages.” Fortunately, Wirth has come up with a simple, elegant HDL called Lola (short for Logic Language), which he presents in this textbook. One feature that enhances Lola’s simplicity is that it is a “genuine HDL,” containing only static descriptions of static objects (namely circuits) and nothing dynamic.

The book is well-rounded and intelligently written at a level suitable for an introductory course in digital circuits. The inclusion of a complete but simple CPU in the text is rare and important. I had been looking for this feature in a digital circuits text for use in elementary digital design classes for a while and had not found it until now.

The book does have some shortcomings, however. Some textual circuit descriptions could have been made clearer with the help of circuit diagrams (such as the barrel shifter, p.90). A more serious shortcoming is that some basic topics in digital design have either been left out or treated very lightly. Two such topics are Karnaugh maps and CMOS complex gates. Basically, these topics have been neglected because the book seems to assume that today’s most popular design styles and methodologies will continue to be so dominant that we can forget about all others. This assumption may not be valid. For example, CMOS complex gates (which are left out of this book) can be far superior to standard cells in terms of energy consumption and layout area without a significant sacrifice in speed. Therefore, they should be incorporated into digital circuits. Well-known algorithms exist for the automatic compilation of complex gates, but no widely available compiler exists. Thus there is a need for a good language for describing complex gates, and a good compiler for such a language that can be integrated into existing CAD systems.

All in all, this digital design textbook is well written and contains valuable information that is not found in any other digital design text.